Hiding in plain sight: The distinct importance of low-arousal positive affect

Abstract

Most past research on positive affect and emotion has focused exclusively on high-arousal positive affect (HAPA: e.g., excited), however, low-arousal positive affect (LAPA: e.g., calm) increasingly is included in emotion research. As such, there is a need to synthesize knowledge about the similarities and differences between LAPA and HAPA, the operationalization of LAPA and HAPA, and the distinct characteristics and importance of LAPA within emotional life. A systematic search identified 226 research papers comparing LAPA with HAPA from a broad spectrum of research topics; this review provides a narrative summary of their findings. Indications of differences between LAPA and HAPA were found in 89% of comparisons, with LAPA having a consistently distinguishable relationship to variables such as brain activity, cardiovascular health, decision-making, memory, mindfulness, personality, and solitude, among others. Other notable aspects of LAPA were found, including its role in stress, work, positive sociality, and well-being, as well as its importance in older adults and women. An analysis of items used to measure LAPA and HAPA revealed nuanced differences in conceptualizations, as well as emerging consensus around specific item usage. While considering item use in light of approach-avoidance motivation, we identified three possible LAPA subtypes: calm (a steady state of neither approach nor avoidance), satisfaction (having successfully approached), and relief (having successfully avoided). This review clarifies LAPA’s role in affective life, underscoring that LAPA’s differences from HAPA should be considered in research involving positive affect.

In recent decades, the study of positive affect and emotions has garnered attention by researchers interested in social behavior and decision making (e.g., Isen, 1987), human evolution and experience (e.g., Ellsworth & Smith, 1988; Fredrickson, 2001; Keltner, 2009; Shiota et al., 2014), health (e.g., Moskowitz, 2003; Pressman et al., 2019), and success (Lyubomirsky et al., 2005) to name just a few. However, much research on feeling good has focused on broad operationalizations of positive states (e.g., happiness, cheerfulness) or on high-arousal positive affect (HAPA) which involves feelings such as excitement or enthusiasm, to the relative omission of low-arousal positive affect (LAPA) which involves feelings such as calm or relaxation.

Multiple researchers have noted this omission. For example, in reviews of research on positive affect/emotion and health, Fredrickson and Cohn (2008) observed that “emotion measures have often conflated pleasantness with either high arousal or high personal control, even though pleasant emotions can span the range of these dimensions” (p. 779). Similarly, Pressman and colleagues (2019) stated that “most studies [on positive affect and health] do not take arousal level into account” (p. 640). In other literature reviews on positive affect and emotion, reviewers have looked for research involving LAPA and noted that it made up only a small fraction of the research included in the review or did not find it at all (Joseph et al., 2021; Liu et al., 2019; Salsman et al., 2019).

After years of relative omission from research on positive affect and emotion, LAPA is increasingly included, along with HAPA, in domains of research as varied as clinical psychology (e.g., Gilbert et al., 2008), cognition (e.g., Fröber & Dreisbach, 2012), cultural valuation of affect (e.g., Tsai, 2017), health (e.g., Schwerdtfeger & Gerteis, 2014), and well-being (e.g., Lomas et al., 2023; McManus et al., 2019). As this research finds that LAPA has distinct causes, associations, and outcomes from HAPA, a need has arisen for synthesized knowledge about how these positive affective states are operationalized, as well as the similarities and differences between them, so that the shape and impact of LAPA can be more fully understood, appreciated, and useful for informing action. To address this need, we conducted a systematic search yielding 226 diverse research papers comparing LAPA with HAPA and provide a narrative review of their findings.

Goals and structure for this review

Our goals for this paper are to provide to researchers and practitioners, in multiple domains of study, insight into the similarities and differences between LAPA and HAPA, the operationalization of LAPA and HAPA, and the distinct characteristics and importance of LAPA. Toward those ends, we first provide background on this topic, outlining the origins of LAPA and HAPA, and underscore why an investigation of LAPA/HAPA comparisons is needed. Next, we describe our methods, noting the systematic steps we took to find, screen, and summarize research comparing LAPA and HAPA. Then, we present narrative summaries of findings within different domains of research, along with tables containing brief descriptions of the pertinent research done in each reviewed article. After, we offer an overview and analysis of the manipulations and measures used for LAPA and HAPA in research reviewed here. Finally, we address questions that motivated the initiation of this review (Are LAPA and HAPA associated with different causes, correlations, and consequences? What characteristics of LAPA might help to explain such differences?) and questions that emerged while reviewing the findings (Does LAPA play a distinct role in integral aspects of life such as stress, work, positive sociality, and well-being? Is LAPA more important for some groups than others? To what degree is approach and avoidance related to LAPA and HAPA, and can integrating these concepts be helpful?) along with implications for future research.

The origins of the LAPA and HAPA distinction

The distinction between LAPA and HAPA is based on a widely accepted approach for organizing emotional experience, often referred to as the circumplex model of affect (Barrett, 2017; Russell, 1980). In this model, emotional experience is thought to be a function of varying degrees of valence (a subjective feeling ranging from negative to positive) and levels of arousal or activation (physiological stimulation ranging from low to high). Valence and arousal have been shown to be independent aspects of emotion (Kuppens et al., 2013). These affective states, which occur on the dimensions of valence and arousal, are referred to as “core affect” and are thought to be readily accessible to the conscious mind; it has been described as “simply feeling good or bad, energized or enervated” (Russell, 2003, p. 145).

It is from a valence/arousal perspective that the most influential measure of positive affect emerged, the Positive and Negative Affect Schedule (PANAS; Watson et al., 1988). The widespread adoption of this measure by researchers interested in positive affect may explain in part why LAPA has been unwittingly omitted from research involving positive affect. The PANAS asks participants to rate the feelings they experienced during a researcher-determined period of time. The items measuring positive affect on the original PANAS included only HAPA states (active, alert, attentive, determined, excited, enthusiastic, inspired, interested, proud, strong). In the original PANAS, LAPA states were not measured directly; states such as calm or relaxed were conceptualized as the absence of negative affect and not included in the scale. In their explanation of the factor structure used in the creation of the PANAS, Zevon and Tellegen (1982, p. 112) described the low end of their scales as referring to “the absence of affect (e.g., ‘sleepy,’ ‘sluggish,’ and ‘tired’ for low Positive Affect and ‘content,’ ‘at ease,’ and ‘calm’ for low Negative Affect).” Even though items directly measuring calm, relaxed, and at ease were included in a later modification of this scale (PANAS-X; Watson & Clark, 1994), the researchers retained the characterization of these states as low negative affect (Watson et al., 1999). The original PANAS continues to be used widely by researchers who may not be aware that they are measuring HAPA and omitting a broad category of good feeling: LAPA.

LAPA hiding in cultural and theoretical blind spots

The classification of states such as calm, relaxed and at ease as low negative affect, without accounting for the positive valence associated with these states, may explain why researchers working with valence/arousal theories have tended to overlook LAPA. But why has LAPA been largely omitted from research on positive affect from the wider field of affective science? We propose three other types of blind spots stemming from cultural and theoretical orientations that may unwittingly undervalue LAPA.

First, researchers may be working within a culture that tends to undervalue LAPA. Until relatively recently scholars were blind to findings of cultural differences in valuing HAPA and LAPA, wherein samples from Western cultures tend to value HAPA more than those from Eastern cultures, and those from the East tend to value LAPA more than those from the West (Tsai, 2017; Tsai et al., 2006). In fact, Tsai’s research on affect valuation and ideal affect drew our attention to the unexamined importance of LAPA, and research on ideal affect is fast growing (e.g., Chim et al., 2018; Tsai et al., 2018, 2019). It may not be a coincidence that after the publication of this eye-opening work in 2006, an increase in research comparing LAPA and HAPA can be observed (see Fig. 1).

Fig. 1

Publication dates for reviewed articles

Second, researchers who work within discrete emotion theory focus their investigations on the characteristics of specific differentiated emotions such as gratitude, pride, and awe, rather than a broader category of affective experience like LAPA (e.g., Shiota et al., 2017). Discrete emotion theories investigate affective experiences that happen on a timescale brief enough to be recognized as a specific emotion (e.g., joy), with concordant physical manifestations (e.g., smile), cognitive appraisal of a situation (e.g., unexpected good fortune), and action tendencies (e.g., play), and these action tendencies are thought to have evolved to serve specific adaptive purposes (e.g., consolidate resources; Fredrickson, 2001). This lens for investigating emotions provides insightful observations and evidence about what can be considered low arousal positive emotions. For example, contentment has been described as a state of satiety or perceived completeness (Campos et al., 2013; Cordaro et al., 2016), serenity has been said to encourage savoring and integration (Fredrickson, 2013), and tranquility has been associated with a focus on process rather than outcome (Berenbaum et al., 2019), clearing one’s mind (Smith & Kirby, 2010), and taking a breather (Lazarus et al., 1980).

However, even when discrete emotion research investigates positive states that could be considered low arousal, researchers tend not to characterize these states as low arousal (e.g., Algoe & Haidt, 2009; Campos et al., 2013; Revord et al., 2021; Yoon et al., 2016). Furthermore, LAPA is not a specific emotion; it is a category that can encompass several specific emotions such as contentment, serenity, and tranquility, along with positive states that are not generally studied by discrete emotion theorists, such as calm, relaxed and at ease. Therefore, investigating the category of LAPA should not replace the investigation of discrete emotions, but should complement it, since LAPA, so construed, may have its own effects, while its component emotions may have distinguishably different effects if investigated at that level of granularity (e.g., Ahn & Shin, 2015).

Finally, researchers working within approach-avoidance theories emphasize motivated goal pursuit, and such an emphasis may obscure affective experience that does not involve pursuing a goal. Approach-avoidance theories emphasize the motivational dimension of emotion, positing that emotions are the experiential components of tendencies to approach desired stimuli and avoid what is threatening or noxious (Carver & White, 1994; Elliot, 2008). Indeed, approach-avoidance theory conceptualizes positive affect as stemming from feedback that suggests progress toward a goal is advancing successfully (Elliot, 2008). Until recently, this theory has generally not accommodated the prospect that an emotion may involve neither approach nor avoidance motivation (see Harmon-Jones et al., 2016 for a relatively recent exception). Carver (2003) situates positive states such as relief, contentment, and serenity on the low end of the dimension of avoidance and introduces the concept of coasting. For Carver, coasting is a signal associated with positive affect that indicates that progress toward a goal is advancing enough that resources can be reallocated to a new goal. We observed that such an emphasis on goal pursuit continues the prioritizing of approach-avoidance over exploring the pleasure associated with no approach/no avoidance.

However, the pleasure of no approach/no avoidance was found to be impactful when Harmon-Jones et al. (2013) found that high-approach motivation positive affect (e.g., excited) narrowed the scope of attention, and low-approach motivation positive affect (e.g., calm) broadened the scope of attention. This research on low-approach motivation affect did much to rouse our interest in LAPA. However, the authors emphasize that approach motivation is not arousal, demonstrating that approach motivation impacts attentional scope, while physiological arousal does not (Gable & Harmon-Jones, 2013).

In sum, each of these perspectives on affect focus on aspects of emotion that reduce the likelihood of investigating LAPA; valence-arousal theories tend to avoid questioning the adaptiveness of different types of affect; discrete emotion theories tend not to investigate broad categories of emotion while considering arousal a relatively uninformative aspect of emotion; and approach-avoidance theories tend not to contemplate emotional states that may be independent of goal pursuit.

Theoretical integration may be needed to make sense of LAPA

Researchers have called for the integration of theoretical perspectives (e.g., Harmon-Jones et al., 2016; Mauss & Robinson, 2009; Smith & Ellsworth, 1985), noting that dimensions such as arousal and approach/avoidance motivation can be descriptors of discrete emotions, and that a lens of adaptive functionality can be used to describe affective dimensions. We suggest that comparisons between LAPA and HAPA make such an integration necessary. Arousal might describe an experiential difference between LAPA and HAPA, but it does not fully explain why LAPA and HAPA would be associated with different causes, consequences, and associations. For such an explanation, LAPA and HAPA should be considered in light of adaptive evolutionary function, motivational qualities, and cultural tendencies; doing so will allow for better descriptions, explanations, and predictions about what LAPA is, how LAPA operates in emotional life, and why LAPA is more or less important for different individuals of different ages and from different cultures.

A model of positive emotion that integrates arousal, approach motivation, and evolutionary adaptiveness was proposed by Gilbert, in his development of Compassion Focused Therapy (2005). Consistent with early theorizing on positive affect that identified two types of innately triggered positive affects (interest-excitement and enjoyment-joy; Tomkins, 1962), Gilbert (2005, 2014) has proposed two types of positive affect that are differentiated by whether the feeling is activating or deactivating. The activating type of positive affect, sometimes referred to as a “drive” system (Richardson et al., 2016, p. 321), is associated with the sympathetic nervous system and dopaminergic brain activity which empowers the body to get up and go for what is wanted and needed, as well as exploring new possibilities. The deactivating type of positive affect, sometimes referred to as a “contentment” system (Richardson et al., 2016, p. 321), is associated with the parasympathetic nervous system, brain activity involving opiates, oxytocin, and neural substrates involved in affiliation and attachment (Depue & Morrone-Strupinsky, 2005), enabling the body to rest and digest (Porges, 2007), restore balance, and feel safety amid familiar stimuli and in connection with others (Gilbert, 2014). This structure of positive affect not only maps well to HAPA and LAPA; it echoes brain-based distinctions in the reward system, where one neuronal system is associated with “wanting” something not yet possessed, and another is connected to a series of hedonic hotspots associated with “liking” something that is familiar (Berridge et al., 2003).

Given the physiological support for Gilbert’s model with its distinction between activating, appetitive positive affect, and deactivating, soothing, and satisfying positive affect, as well as its similarity to Tomkins’ (1962) postulates about positive affect, we used this review as an opportunity to look for literature that might provide further insight into whether HAPA and LAPA are respectively high and low in approach motivation. We sought, in part, to clarify whether the distinction between LAPA and HAPA is simply a difference in arousal or whether the difference in arousal signals a more complex and complementary function of positive affect as suggested by Gilbert (2014) and Tomkins (1962).

The case for investigating LAPA in contrast to HAPA

We see two primary reasons for investigating LAPA in contrast to HAPA. The first reason responds to the aforementioned blind spot within valence/arousal theories, where the cost of the omission of LAPA must be clarified. The second reason is to provide practitioners and lay people insight into the importance of the broad category of emotion that LAPA represents, by looking at LAPA’s relationship to motivation (drawn from approach/avoidance theories), as well as LAPA’s distinguishing characteristics and purpose (in a similar vein as discrete emotion theories). Furthermore, LAPA may be particularly useful for developing a more robust meta-emotional awareness, which involves attentiveness to, clarity for, and non-judgment of emotion, along with beliefs about the value and utility of emotion (Berenbaum & Chow, 2019; Gottman et al., 1996). LAPA may also play a meaningful role in an instrumental approach to emotion regulation (Tamir, 2009). Tamir (2016) emphasizes there are multiple motives for regulating emotions beyond optimizing immediate pleasure, that people also engage in emotional regulation to enhance their ability to accomplish what is meaningful to them over a longer time horizon. If people can, to some degree, choose from a menu of emotional states to shape their lives, it is important to understand what LAPA is good for, so that it can be integrated into strategies for emotional regulation.

Furthermore, we suggest that distinguishing the broad category of LAPA from the broad category of HAPA may be especially useful for those who do not readily identify distinctions in what they are feeling, those with low emotional granularity (Barrett & Bliss-Moreau, 2009). Indeed, Barrett (2017) emphasizes that an important advantage of a dimensional perspective is that it may better allow people of low emotional granularity to identify their inner experience. A deeper understanding of the usefulness of LAPA, which as a broad category of emotion could be more readily recognized than specific emotions with nuanced distinctions, may serve as a worthy first step for developing greater positive emotional granularity and reaping the benefits thereof (Tugade et al., 2004; Wilson-Mendenhall & Dunne, 2021).

Method

Search

To find articles for this review, we focused our search terms on LAPA, since it has been studied much less frequently than HAPA; such an approach provided a more streamlined set of articles in which to look for comparisons between LAPA and HAPA. Our initial search (see Fig. 2) took place in April 2019 and used the following search terms: “low arousal positive affect,” “low arousal positive emotion,” “low activated positive affect,” and “low activated positive emotion.” These search phrases were in quotation marks when searching Google Scholar, but they were not in quotation marks when searching Web of Science and PsycINFO. The Web of Science results for “low activated positive affect” were further refined, such that we limited the results to articles that included “emotion,” “affective,” or “feeling,” in order to avoid results from non-human fields, such as environmental or veterinary science.

Fig. 2

Reduction flow

An expanded search took place in July 2022, this time focusing on Google Scholar, which we had observed to yield results with fewer duplications and wider coverage of recently published research than the other databases. The search terms used in the expanded search were “positive deactivation,” “pleasant deactivation,” “positive low activation,” “positive deactivating affect,” “positive deactivating emotion,” “calm AND excitement (no quotes),” and “calm AND enthusiasm (no quotes).” We inspected results from other search terms (e.g., “contentment and excitement”) and observed that such results primarily contained items that did not meet our inclusion criteria. Additionally, in the process of inspecting articles or searching for contextual information, when we encountered articles that appeared to match our inclusion criteria, we investigated them and included those that matched. See Fig. 2 for more information about our search.

Inclusion/exclusion criteria

The inclusion criteria for articles in this review were as follows: (1) the paper must be available in English; (2) the article must have positive affect clearly conceptualized as varying in high and low arousal as an object of investigation; (3) there must be an empirical comparison between HAPA and LAPA; (4) the paper must have reported how HAPA and LAPA were measured, manipulated, or coded; (5) the results of the HAPA/LAPA comparison must have been clearly reported, discussed or displayed in tables or figures; and (6) the article must have been published in a peer-reviewed journal. After working with the articles meeting these criteria, we added an exclusion criterion: (7) articles whose main object of study was cultural differences in ideal affect were omitted due to the difficulty in disentangling the mediating effects of ideal affect and actual affect (see Tsai, 2017 for an overview of this important literature).

Selection process

The selection process followed the steps outlined by Moher et al. (2009). After obtaining the articles, titles were scanned and non-English and duplicate results were removed, as were encyclopedia entries. Abstracts were reviewed for evidence that affect or emotion was investigated. The text of articles was searched for key words (e.g., arousal, activated, calm). See Fig. 2 for details about the reduction flow. Selection decisions were primarily made by the first author. The reliability of such decisions was tested by presenting a random sample of articles (20 from 398 articles that had been marked for close reading) to a research assistant who was blind to the goals of the current research and the status of each article. The assistant used the inclusion criteria to assign an inclusion status for each article. Agreement was found on 18 of the 20 articles, k = 0.79. The two cases of initial disagreement were resolved by further inspection of the operationalization and reporting of each article. Additionally, the first author identified 42 articles where the inclusion decision was a close call, presented them to research team members, and consensus was achieved.

Data extraction, narrative review, table structure

We began data extraction by reading each article and recording sample size and type, dependent and independent variables, covariates, procedural details, measurement items, manipulations, and findings. It was soon evident that our dataset included a wide variety of methods, measures, and manipulations. Most importantly, LAPA or HAPA was sometimes the outcome variable, sometimes the independent variable, sometimes a moderator, and less frequently a covariate, and there was almost no overlap in what was being investigated (see Table 4, Developmental research, for an exception).

With such a wide variety of procedural approaches and range of outcome variables, we decided to narratively summarize the findings (Siddaway et al., 2019). Our goal was to provide an overview of similarities and differences between LAPA and HAPA along with integrative theoretical perspective, and a narrative review is consistent with such a goal (Möschl et al., 2020). This decision determined the format of the tables we use to report these findings, following the example of other narrative reviews (e.g., Frick et al., 2014; Ging-Jehli et al., 2021). In addition to providing information about the sample, procedures, operationalizations, and findings, we reported the country in which the research was conducted. Most papers reported the country from which the sample was drawn, but when they did not, we report the country associated with the first author. See Table 1 for the frequency with which research was conducted in each country.

Table 1 Frequency of countries reported by articles that identified the location of their samples

Organization of findings

The search parameters did not limit results to psychological domains, but the majority of articles that met our inclusion criteria were published within the field of psychology. The final categories we used to organize findings were informed by the chapter structure of standard psychology textbooks and a recently published handbook on emotion (Barrett et al., 2016).

Transparency and openness

In our commitment to transparency, we report how we determined our sample size, all data exclusions, all manipulations, and all measures (if any) in the study. Even though this research was not preregistered, we make available on the Open Science Framework (https://osf.io/69cha/) working documents that were essential to our finding, selecting, coding, and interpreting articles included in this review.

Summaries of findings

The breadth and variety of research comparing LAPA and HAPA surprised us. Our assumptions about the relative omission of LAPA from emotion research did not account for research that used affect to reveal qualities of a specific target of interest that is not necessarily thought of in terms of affect. For example, we found LAPA/HAPA comparisons in studies about driving (Schmidt et al., 2017), pro-environmental behavior (Bissing-Olson et al., 2013), aircraft noise (Västfjäll et al., 2003), and evaluations of undergarments (Greggianin et al., 2018). In fact, roughly one fifth of article titles in this review did not mention emotion, indicating that there is pervasive relevance of affective inquiry across domains. While similarities between LAPA and HAPA were regularly found, differences between them were found in 89% of the articles in this review. In our summaries of findings, we highlight aspect of LAPA’s causes, associations, and consequences that are distinct from HAPA, so as to underscore the importance of including LAPA in research on positive affect, while noting theoretical implications where relevant.

Cognitive research (Table 2)

Within the realm of cognition, LAPA has been found to be a help or hindrance to cognitive processes in ways that are consistent with theory that associates one type of positive affect with novelty and drive (HAPA) and another type of positive affect with familiarity and safeness (LAPA; Gilbert, 2005; Tomkins, 1962). For example, LAPA tends to be either unrelated to, or a negative influence on, cognitive processes that involve new ideas such as creativity (De Dreu et al., 2008; Gilet & Jallais, 2011; Hutton & Sundar, 2010; To et al., 2012) or goal-directed thought such as attentional control (Fröber & Dreisbach, 2012; Jefferies et al., 2008; Tibboel, 2018). Indeed, Fröber and Dreisbach found that LAPA, but not HAPA, reduced proactive control (using cues to predict an upcoming task) but not reactive control (responding to cues presented concurrent with a task).

Table 2 Cognitive research

Along these lines, LAPA may provide advantages to cognitive processes that involve familiarity, such as recollection amid distractions (Saxton et al., 2020) or other memory tasks involving photo recall (Bergmann et al., 2012; Steinmetz et al., 2010; Wang & Yang, 2017), false memories of spoken words (Corson & Verrier, 2007) and images (Van Damme & Smets, 2014), as well as recall of positive words (Loeffler et al., 2013). Furthermore, the association between LAPA and safeness is supported by findings that participants made less risky decisions in a LAPA condition compared to HAPA (Galentino et al., 2017). Though other studies found that LAPA leads to faster decisions of discernment than HAPA (Citron et al., 2014; Ihssen & Keil, 2013; Robinson et al., 2004; Trick et al., 2012), some associated LAPA with slower decisions (Fernandes et al., 2011; Orlić et al., 2014). Still others did not find a difference between LAPA and HAPA on cognitive processes (Eder & Rothermund, 2010; Lu et al., 2017; Roesch, 1999; Tauber et al., 2017; Van Damme & Seynaeve, 2013).

It may be that differences in cognition between LAPA and HAPA depend on the extent to which they are high or low in approach motivation, especially in light of findings that high-approach motivation positive affect narrows attention, and low-approach motivation broadens attention (Harmon-Jones et al., 2013). The findings of one study reviewed here is consistent with a narrowing and broadening of attention; HAPA was associated with recollecting details, and LAPA was associated with recollecting context (Wang et al., 2018). Though more research is needed to make sense of disparate results within research on cognition, we propose that conceptually linking HAPA to novelty, drive, and appetite, while linking LAPA to familiarity, safeness, and satisfaction may be useful for investigating potential distinctions.

Consumer research (Table 3)

In studies of consumer experiences, LAPA’s distinctions from HAPA appear to be consistent with models of positive affect organized by desire or resource seeking (HAPA) and contentment or soothing (LAPA; Gilbert, 2005). This can be seen in research that associates HAPA with an orientation toward the future, or moving toward something that is desired, while LAPA is associated with an orientation toward the present, or enjoying the resources at hand (Mogilner et al., 2012). Furthermore, having high expectations, another future-oriented stance, was associated with HAPA but not LAPA (Aurier & Guintcheva, 2014). Indeed, in a qualitative analysis of positive affect and consumer experiences, HAPA was associated with anticipation, but LAPA was not, and the qualities associated with LAPA were feeling safe, unconcerned about time, and physically comfortable (Pham & Sun, 2020). Another novelty-related distinction can be observed in findings that LAPA was associated with lower intentions to adopt new technology, while HAPA was associated with higher intentions to do so (Ahn & Shin, 2015).

Table 3 Consumer research

Consistent with the lower arousal level of LAPA, when marketing or commercial setting were energetic, exciting, or complex, a reduction in LAPA (but not HAPA) was observed (Greggianin et al., 2018; Henning et al., 2012; Wang et al., 2017). And, as might be indicated by the soothing qualities of LAPA, interpreting extreme complexity in marketing messaging was found to be aided by LAPA, while interpreting messaging of moderate complexity was aided by HAPA (Noseworthy et al., 2014). In keeping with LAPA’s relationship to feeling safe, for riskier decisions, LAPA smiles were associated with a higher likelihood for signing up for a service, but for less risky decisions HAPA smiles were associated with a higher likelihood of signing up (Wang et al., 2017). Further evidence that LAPA is not associated with acquisitiveness can be seen in findings that LAPA was less likely than HAPA to increase trading bubbles, where prices go up despite decreasing value (Andrade et al., 2016).

Along with the proposition that LAPA is related to the familiar and safe, LAPA has been thought to be associated with positive, caring social interaction (Gilbert et al., 2008; Tomkins, 1962), and support for this can be found in some consumer experiences wherein the social interaction or the interpretation of social interaction was more positive in conditions involving LAPA compared to conditions involving HAPA (Chou et al., 2022; Panger, 2018; Seering et al., 2019), though some studies found that both LAPA and HAPA have a similar relationship to social situations (Andersson et al., 2016; Dubé et al., 1995).

Developmental research (Table 4)

One of the strongest indications that LAPA should not be ignored is the robust finding that, as adults grow older, LAPA becomes more prevalent, so much so that some researchers have suggested that LAPA emerges as a distinct form of happiness for older adults (Bjalkebring et al., 2015; Mogilner et al., 2011). Critically, researchers note when LAPA is not accounted for, that data can be misleading, suggesting that older adults are unhappier than younger adults (e.g., Pinquart, 2001). Multiple studies have found that levels of LAPA are higher among older adults than younger adults (Chu et al., 2020; English & Carstensen, 2014; Hamm et al., 2021; Ready et al., 2019; Santorelli et al., 2018; Scheibe et al., 2011; Simon & Nath, 2004), even after controlling for gender, health, and personality traits (Kessler & Staudinger, 2009). Though some studies found that LAPA was experienced to a similar degree among older and younger adults when measured longitudinally (Hudson et al., 2016) or after work (Scheibe et al., 2016), no studies found that LAPA was lower in older adults compared to younger adults.

Table 4 Developmental research

The findings are not as clear cut when comparing HAPA in older and younger adults. Most studies find that HAPA is experienced to a similar degree by older and younger adults (English & Carstensen, 2014; Hudson et al., 2016; Kessler & Staudinger, 2009; Ready et al., 2019; Santorelli et al., 2018; Scheibe et al., 2016). Other studies have found that older adults experience HAPA less than younger adults (Hamm et al., 2021), but only when assessments were taken cross-sectionally, not longitudinally (Hudson et al., 2016). Still other studies have observed more HAPA in older adults than younger adults (Chu et al., 2020; English & Carstensen, 2014).

Differences between HAPA and LAPA appear to start early and continue steadily across the lifespan. Starting at two years old, children identified LAPA facial expressions as different than HAPA facial expressions (Russell & Bullock, 1986), and throughout childhood, the younger the child, the more likely the preference for HAPA over LAPA (Hunter et al., 2011), and younger children reported higher HAPA than older children (Raccanello et al., 2020). The trend continues into adulthood, with the fall of HAPA and rise of LAPA being relatively linear across the adult lifespan (Bjalkebring et al., 2015; Kern et al., 2014; Mogilner et al., 2011).

Studies in this review explored possible explanations for higher levels of LAPA in older adults, including their health, in that declining physical vigor causes older adults to choose emotional states that are physically less taxing (e.g., Windsor et al., 2013). Using data from several longitudinal studies in Australia (N = 39,958), Windsor and colleagues found that overall, after controlling for limitations in physical functioning such as bathing, dressing, and climbing stairs, the positive association between age and LAPA was strengthened, while the negative relationship between age and HAPA was reversed. Other studies indicate that this pattern of difference in positive affect in older adults and younger adults is related to memories (Mickley & Kensinger, 2009; Narme et al., 2016), cognitive function (Leclerc & Kensinger, 2008), meaning in life (Chu et al., 2020), and diminished future time perspective (Mogilner et al., 2011). Though more research is needed to explain the shift toward LAPA across the lifespan, the robustness of these findings underscores the importance of LAPA to the human experience of emotion.

Education and training research (Table 5)

Research involving education and training provides, to some extent, support for the view that HAPA facilitates achievement and LAPA facilitates a sense of safeness (Gilbert et al., 2008). In one study, when an exam was framed as a threat, LAPA was decreased and HAPA unaffected, while framing the exam as a challenge increased HAPA without impacting LAPA (Skinner & Brewer, 2002). It may be this relationship to threat, and the possibility that many people experience educational tasks as threatening, that explains the findings of several studies that LAPA, more so than HAPA, was associated with beneficial learning processes in settings such as online (Howardson & Behrend, 2016), in smaller conversational groups (Hendrix & Morrison, 2020), during medical training scenarios (Fraser & McLaughlin, 2019; Fraser et al., 2012), and during mental imagery sessions to improve dart throwing (Kuan et al., 2018). It has less frequently been found that LAPA and HAPA had similar beneficial effects (Young et al., 2021) or HAPA had more beneficial effects (Brooks, 2014). Understanding HAPA as driving and LAPA as soothing, along with understanding the learners’ contexts, could yield fruitful predictions for the effects of positive affect on educational performance and learning.

Table 5 Education and training research

Emotion and affect research (Table 6)

Research where the object of interest is affect and emotion itself provides clues about why LAPA has been overlooked and underscores why it should not be. One possible explanation for the omission of LAPA from research on positive affect is its close proximity to emotional neutrality (Gasper et al., 2021; Kirkland & Cunningham, 2012), involving fewer thoughts that lead to action (Sugawara & Sugie, 2020), thus rendering LAPA less noticeable than HAPA. However, even if LAPA does not demand attention or spur activity, it is most decidedly associated with feeling good. In research on happiness from around the globe, when people define happiness, they are more likely to include LAPA than HAPA in their definitions (see Delle Fave et al., 2016, described in Table 13). Additionally, when participants in Germany were asked to generate a positive state without any further elaboration or instruction, people reported feeling LAPA more frequently than HAPA (Engen et al., 2017). In Sweden, happiness was higher when it was framed as LAPA and lower when it was framed as HAPA, when compared to a control condition (Bjalkebring et al., 2015, described in Table 4). So even though LAPA may be considered to be similar to neutrality, its valence is as (or more) positive than HAPA, and as such any conceptualization of positive affect that does not include LAPA is incomplete.

Table 6 Emotion and affect research

Health research (Table 7)

Research from the health domain highlights the importance of including both HAPA and LAPA in research on positive affect and health, since important differences can be found in how each type of positive affect relates to health, and these differences largely align with what would be expected from positive affect that activates and positive affect that deactivates (Gilbert, 2005, 2014; Tomkins, 1962). First, HAPA and LAPA have different relationships to the autonomic nervous system in response to pain. Even though both HAPA and LAPA were associated with an increase in the soothing parasympathetic response to pain, they had opposite effects on the action-oriented sympathetic response to pain, in that LAPA buffered the sympathetic response, while HAPA amplified it (Acevedo et al., 2020).

Table 7 Health research

Second, LAPA and HAPA relate differently to cardiovascular health, with findings that LAPA is associated more consistently than HAPA with indicators of heart health, including good cholesterol (Shirom et al., 2009), lower blood pressure (Armon et al., 2014), and better cardiac function such as heart rate variability (Lynar et al., 2017; Petrocchi et al., 2017; Reynaud et al., 2012), pre-ejection period (Neumann & Waldstein, 2001), and vagal tone (Lane et al., 2011; Schwerdtfeger & Gerteis, 2014). However, when it comes to vagal tone, trait HAPA (as opposed to momentary) is associated with better vagal tone than trait LAPA (Schwerdtfeger & Gerteis, 2014), and one study found the beneficial relationship to vagal tone to be limited to a safe/content factor of LAPA (Duarte & Pinto-Gouveia, 2017).

Third, LAPA and HAPA relate differently to sleep, with evidence that LAPA is beneficial to various aspects of sleep such as sleeping longer, shorter bouts of waking during the night, and falling asleep more quickly (Tavernier et al., 2016) and a lower heart rate and better heart rate variability while sleeping (Schwerdtfeger et al., 2015). However, one study found that LAPA’s association with better sleep efficiency was limited to days of high stress (Pressman et al., 2017).

Fourth, LAPA and HAPA relate differently to exercise, with evidence that HAPA is increased during exercise (Lathia et al., 2017) and immediately following exercise (Petruzzello et al., 2001; Stevens et al., 2016; Williams et al., 2011). However, LAPA induced by music has been found to promote recovery from exercise (Karageorghis et al., 2018) and LAPA experienced during exercise predicted higher levels of physical activity 45 min later compared to those who experienced HAPA (Kanning & Schoebi, 2016).

Finally, LAPA and HAPA relate differently to substance abuse and addictive behaviors, though the evidence does not seem to be well explained by theory. For example, heavy episodic drinking was predicted by higher levels of momentary HAPA (not LAPA) and trait LAPA (not HAPA; Jones et al., 2021). Moreover, beer consumption was increased by both LAPA and HAPA, but for those with trait positive urgency, LAPA decreased beer consumption, while HAPA increased it (Dinc & Cooper, 2015). It is possible that such a result could be related to the finding that beer has been found to be associated with HAPA and wine with LAPA (Silva et al., 2016). Smoking relapse among teens was less likely when experiencing LAPA and more likely when experiencing HAPA (Padovano et al., 2020), but for adults this pattern was not found (Holt et al., 2012). Different approaches to treating substance abuse impact positive affect differently; treatment that includes contingency management, a system for building skills based on operant conditioning, increases HAPA more so than LAPA, while treatment that includes individualized plans, which involves careful observation of actual behavior in order to target specific behaviors, increases LAPA more so than HAPA (Litt et al., 2021). Such a finding could be seen as consistent with the view that HAPA is related to achievement and LAPA is related to interpersonal support (Gilbert, 2005, 2014).

Neurological and physiological research (Table 8)

Differences between LAPA and HAPA in terms of brain activity have been found in electroencephalogram (EEG) studies measuring the amplitudes of brain waves (da Silva et al., 2016; Leite et al., 2012; Sommer et al., 2016), as well as in functional magnetic resonance imaging (fMRI) studies involving viewing images (Nielen et al., 2009) and listening to music (Trost et al., 2012). Trost and colleagues emphasized that “no brain structure was activated in common by all pleasant music experiences independently of the degree of arousal. This further supports the distinction of positive emotions into two distinct clusters” (p. 2780). Furthermore, these findings provide support for associating HAPA with drive (Gilbert, 2005, 2014) in that HAPA, more so than LAPA, was associated with brain regions involved in motivated attention (Leite et al, 2012).

Table 8 Neurological and physiological research

Among these findings there is support for the proposition that LAPA is associated with the familiar, in that low-arousal positive emotions were related to areas of the brain associated with memory (Trost et al., 2012). Furthermore, as would be expected, LAPA is found to have a lower galvanic skin response, a measure of arousal, than HAPA (Aguado et al., 2016; Lynar et al., 2017; Reynaud et al., 2012), as well as less movement of muscles associated with smiling (Aguado et al., 2016; Reynaud et al., 2012). Additionally, support for the proposition that HAPA is associated with action and alertness was observed, in that HAPA was related to upright posture (Nair et al., 2015; Wilkes et al., 2017), as well as cooler temperatures (Schmidt et al., 2017) and better braking while driving (Trick et al., 2012).

Perception and sensation research (Table 9)

In keeping with operationalizations of LAPA that include “warm” (Gilbert et al., 2008), research on perception and sensation, supports an association between LAPA and warmth as well as other soothing sensations, such as warm reddish lighting (Kim & Mansfield, 2021; Kuijsters et al., 2015), indirect sunlight (Boubekri et al., 1991), and softer sounds (Västfjäll et al., 2003). Conversely, HAPA has been associated with cool bluish lighting (Kim & Mansfield, 2021; Kuijsters et al., 2015), higher toned sounds (Västfjäll et al., 2003), and sweet tastes (Jaeger et al., 2018, 2019). Research on time perception may be potentially important in light of theory and research that associates LAPA with an orientation toward the present moment (Mogilner et al., 2011, 2012). However, findings are mixed; LAPA has been associated with overestimating time duration (Angrilli et al., 1997), accurately estimating time duration (among healthy controls) and underestimating time duration (among manic patients; Ryu et al., 2015). Without more research, finding a pattern in positive affect and estimating time duration is elusive.

Table 9 Perception and sensation research

Personality research (Table 10)

Research on the relationship of different types of positive affect to personality traits has consistently indicated differences in LAPA and HAPA but has not yet yielded a discernable pattern. We observed that LAPA and HAPA are each related to different types of desirable traits, and that neither is a clear marker of a better way to be. Such findings are consistent with the proposition that LAPA and HAPA may be more relevant for people based on their different needs and contexts. However, Ditzfeld and Showers (2014) noted a possible concern about an orientation toward HAPA, and by implication, a possible benefit of LAPA, when they wrote, “We suggest that some affective cores indeed do burn hotter than others. And with these hotter cores comes higher arousal and less stable affect” (p. 597).

Table 10 Personality research

Extraversion and neuroticism were the most frequently studied personality traits, and the findings are difficult to interpret. We expected that introverts might have an affinity for LAPA, but no personality-based differences were found between LAPA and HAPA in moments of daily life (Komulainen et al., 2014) nor at work (Madrid & Patterson, 2014, see Table 14). However, personality may impact what emotional experiences are remembered; one study found that those higher in extraversion and having lower or higher levels of neuroticism were more likely to exaggerate past experiences of HAPA and underreport LAPA (Lay et al., 2017). In keeping with the view that LAPA is associated with soothing (Gilbert et al., 2008), neuroticism (being more sensitive to threat and negative emotion) amplified LAPA’s positive effect on attention, but was unrelated to HAPA (Siyaguna et al., 2019).

Research on other traits indicates that LAPA has been found to be more prominent than HAPA in the lives of those high in agreeableness (Komulainen et al., 2014), low in reward seeking (Kuppens, 2008), integrated self-structure (Ditzfeld & Showers, 2014), prevention focus (Wang et al., 2017, see Table 3), with overwhelmed emotional processing style (Sperry & Eckland, 2021) and empathizers (Greenberg et al., 2015). HAPA has been found to be more prominent than LAPA in the lives of those high in reward seeking (Kuppens, 2008), with compartmentalized self-structure (Ditzfeld & Showers, 2014), promotion focus (Wang et al., 2017, see Table 3) and systemizers¹ (Greenberg et al., 2015). Taken together, the traits that cluster around HAPA are indicative of reward-seeking, and those that cluster around LAPA are indicative of positive sociality, a realistic sense of self, and a tendency to avoid losses instead of seeking gains.

Psychological disorders (Table 11)

Accounting for the difference between LAPA and HAPA could be essential for understanding and treating psychological disorders. For example, Gilbert and colleagues (2008) emphasized that the gentle feelings associated with LAPA serve as a signal of social safeness and respite from activating emotions, suggesting that it plays a healing role in therapeutic settings and daily life. Indeed, researchers found that LAPA, particularly when the measure of it includes safeness and security, has been found to predict lower levels of depression, anxiety and stress (Gilbert et al., 2008; McManus et al., 2019), as well as self-criticism, and insecure attachment (Gilbert et al., 2008). One possibility is that people with depression are less likely to notice low arousal positive states, in light of research that indicates people with depression are less likely than healthy controls to remember LAPA words, but not HAPA words (Deldin et al., 2009). Even if LAPA plays a role in the experience and treatment of depression, it may not be effective at increasing help seeking for depression, given that HAPA, but not LAPA, has been found to increase help seeking intentions (Straszewski & Siegel, 2020), which is consistent with the view that HAPA is associated with spurring action (Gilbert et al., 2008).

Table 11 Psychological disorders

The distinction between LAPA and HAPA can help reveal the emotional goal associated with certain dysfunctional behaviors. For example, LAPA could be considered an emotional goal for some types of self-harm. Particularly when the measure of LAPA includes relief, LAPA has been found to increase for those having just engaged in non-suicidal self-injurious behavior such as cutting, burning, or self-shocking (Ammerman et al., 2018; Claes et al., 2010; Di Pierro et al., 2014; Klonsky, 2009; Kranzler et al., 2018) as well as bulimia (Becker et al., 2018; Cooper et al., 1988). However, HAPA can be seen as an emotional goal for manic behavior, as is suggested by research indicating that hypomanic patients are more likely to endorse HAPA words, but not LAPA words, compared to healthy controls (Pyle & Mansell, 2010). Furthermore, HAPA has been found to elicit reactivity among people suffering from schizophrenia (Lakis et al., 2011; Phillips et al., 2007) and anhedonia (Heininga et al., 2017), suggesting that HAPA may pose risks that LAPA does not. Finally, there is evidence that LAPA may be less disrupted by trauma than HAPA (Bunce et al., 1995), which suggests the possibility that LAPA might be an overlooked resource for resilience in the face of traumatic events.

Relationships and solitude (Table 12)

Differences found between LAPA and HAPA in the realm of relationships and solitude can be considered to be consistent with Gilbert’s (2005) proposition that, in contrast to the type of positive affect that encourages reward seeking and achievement (e.g., HAPA), the type of positive affect that signals safety (e.g., LAPA) recruits the same neural pathways as those involved in secure attachment and affiliation (Depue & Morrone-Strupinsky, 2005). As direct evidence, LAPA (a safe/content subscale) was positively related to secure attachment among adults, while HAPA was not (Gilbert et al., 2008). Indirect evidence also supports this theory. If we infer that mothers tend to be the primary attachment figure in infants’ lives, the relationship between LAPA and attachment security is supported by the finding that LAPA and medium arousal was more characteristic of mothers’ interaction with infants, while fathers were observed to interact with infants in playful ways, more characterized by HAPA (Feldman, 2003). Furthermore, for romantic partners whose implicit motivation was for affiliation in the relationship, having more LAPA was satisfying, while in romantic partners whose implicit motivation was for power, having more HAPA was satisfying (Job et al., 2012). Additionally, among those with avoidant attachment style, LAPA (but not HAPA) was decreased in response to being asked to savor an interpersonal event (Palmer & Gentzler, 2018). Finally, when people find moments of social contact satisfying, both HAPA and LAPA are higher in that moment, but only LAPA is still elevated two hours later (Liu et al., 2021).

Table 12 Relationship and solitude research

In as much as the above research suggests that LAPA may be involved in safeness among other people, a different kind of safeness might be experienced in everyday moments of being alone; moments of solitude were consistently associated with higher LAPA and lower HAPA (Lay et al., 2019; Nguyen et al., 2018; Pauly et al., 2017, 2018). However, more research is needed to explain why and under what conditions LAPA increases during moments of solitude. Pauly and colleagues posited that these low arousal positive moments of solitude may promote “self-reflection, creative thinking, and emotional renewal” (2017, p. 63).

Well-being and mindfulness (Table 13)

Research on well-being and mindfulness are prime examples of the benefits of upending assumptions that conflate positive affect with HAPA. Even though some research supports HAPA’s primacy relative to LAPA in association with well-being constructs such as meaning in life (Chu et al, 2020), flow (Collins et al., 2009), gratitude (Jans-Beken et al., 2019), basic psychological needs (Gui et al., 2019), fun (Reis et al., 2017) and identity integrity (Chishima & Nagamine, 2021), the inclusion of LAPA in study designs has clarified understandings of mindfulness and happiness. Early research on mindfulness often failed to find a significant relationship between mindfulness and positive affect when using only HAPA items to measure positive affect (e.g., Chambers et al., 2008; Davis & Zautra, 2013; Jislin-Goldberg et al., 2012). However, one of the most consistent findings of this review is that mindful practices tend to increase LAPA but not HAPA (Imtiaz et al., 2018; Jones et al., 2018; Kerekes et al., 2017; Lymeus et al., 2018; Rowland et al., 2020; Zeng et al., 2019). Albeit, some specific types of meditation, such as a positive empathy meditation, show a different pattern (Zeng et al., 2017). Still, it may be fair to say that LAPA, feeling calm, relaxed, and content, is a signal of success for developing the equanimity, acceptance, and non-judgement associated with mindfulness.

Table 13 Well-being and mindfulness research

Regarding happiness, research that allows LAPA to be included in the definition of happiness exposes the error of conflating happiness with feelings such as excitement, elation, and exuberance (HAPA). Delle Fave and colleagues (2016) conducted interviews with people in 12 countries on five continents, asking them to define happiness. Among the many aspects of happiness described, affective qualities were coded, and LAPA qualities such as peace of mind, harmony, and contentment were mentioned in roughly 30% of descriptions, while HAPA qualities such as joy, vitality, and enthusiasm were mentioned in roughly 14%. This emphasis on LAPA was echoed in a study of conceptualizations of well-being in Ghanaian languages (Osei-Tutu et al., 2020). The importance of LAPA to happiness across the world was confirmed by a recent Gallup World Poll, which introduced a question that asked participants if they prefer feeling calm or excited; in nearly all of 116 surveyed countries (96%), a majority of people reported a preference for calm (Lomas et al., 2023).

To better understand the importance of either type of positive affect when both are related to a construct, the relationship can be investigated by assessing the degree to which HAPA or LAPA uniquely explains variance in a construct after controlling for the other. Such was the design of research conducted by McManus and colleagues (2019), who assessed levels of affect along with mental health and well-being outcomes, and through multiple regression analysis identified the predictive power of LAPA above and beyond HAPA. LAPA uniquely explained a significant portion of the variance in life satisfaction, feeling good, depression, anxiety, stress, and mindfulness after the variance explained by HAPA had been accounted for. Such results underscore the findings of many studies in this review; even though these positive affective states are highly related, HAPA and LAPA each have unique relationships to many aspects of life, and both should be accounted for when investigating well-being.

Work and leisure (Table 14)

Differences between LAPA and HAPA at work can be explained to some degree by the proposition that low arousal positivity is associated with support and safety and high arousal positivity is associated with drive and achievement (Gilbert, 2005, 2014). For example, LAPA is higher when workers get support (Popa-Velea et al., 2021) and practice self-compassion (Kreemers et al., 2020). Furthermore, when workers describe positive incidents they had with leaders, they were more likely to use LAPA words than HAPA words (Dasborough, 2006). Conversely, LAPA is lower when workaholism is high (Balducci et al., 2012) and when jobs are more demanding (Madrid & Patterson, 2014; Warr, 1992). This may explain the lower levels of LAPA in lower status jobs such as housekeeping (Urick et al., 2018) as well as jobs associated with higher status (Warr, 1992). An indication that LAPA is not associated with drive can be seen in research showing that more LAPA was related to less task engagement (Salanova et al., 2011).

Table 14 Work and leisure research

On the other hand, indications that HAPA is associated with drive can be seen in research showing that more HAPA was related to higher task engagement (Salanova et al., 2011), more proactive behavior at work (Ouyang et al., 2019), and more unethical behavior done to benefit others (Umphress et al., 2020). Additionally, an association between HAPA and achievement can be inferred from findings that leaders who exhibited more HAPA were rated as more charismatic (Damen et al., 2008) and effective (Connelly & Ruark, 2010). Moreover, those with higher organizational influence experience more HAPA (Warr, 1992) especially when their work networks are larger (Totterdell et al., 2004). Furthermore, an important element of achievement is effectiveness, which is associated with HAPA, in that HAPA but not LAPA was associated with job search systematicity, an adaptable and persistent approach to finding a job which predicted actually finding a job (Kreemers et al., 2021).

Findings suggest that, in the complexity of work environments, there may be an interplay of support and achievement, as well as an interplay of LAPA and HAPA, in that LAPA and HAPA are both related to many work-related constructs such as perceived justice (Cassar & Buttigieg, 2015), communication with colleagues (Monnot & Beehr, 2014), and effectiveness and confidence in meetings (Rogelberg et al., 2006), following leaders high in either type of positive affect (Kelloway et al., 2013), and innovation at work (Laguna et al., 2021).

Studies on leisure and commuting provide fairly consistent indicators that LAPA is more strongly tied to nature than HAPA. One study found that only LAPA was heightened during leisure activities, particularly walking in nature and sitting in rooms with a view of nature, but less so for walking in urban settings (Hull et al., 1996). Furthermore, cycling to work has been found to consistently increase LAPA (de Kruijf et al., 2019; De Vos, 2018), while car and public transport were associated with heightened HAPA (De Vos, 2018). Still, each type of positive affect was differently impacted by different aspects of nature; when cycling to and from work, LAPA was higher on warmer days and HAPA was higher on windy days (Ettema et al., 2017).

Overall, as would be expected with the relaxing qualities associated with LAPA, LAPA is higher at home and at leisure, and HAPA higher at work (Sandstrom et al., 2017). Furthermore, LAPA may be a buffer against negative spillover from work to home, in that weeks with more LAPA were associated with less work-nonwork interference, and weeks with HAPA were associated with more work-nonwork interference (Wood & Michaelides, 2016).

Operationalizations

Manipulations of LAPA and HAPA

Among all the articles in this review, 70 articles (31%) reported manipulating HAPA and LAPA. Among the articles that manipulated affect, most of the research that manipulated HAPA and LAPA was within cognitive psychology (39% of articles that manipulated affect). Manipulations of positive affect involved photos (46%), music (23%), words (13%), recollections (11%), guided imagery (6%), and film (6%). Information about photo manipulations is reported in Table 15, mood manipulations in Table 16, and specific music manipulations in the various summary tables (e.g., Bolders et al., 2017, see Table 9).

Table 15 Themes and IAPS numbers (where available) for photos used for affect manipulation

Table 16 Prompts used for mood inductions

Types of measures of LAPA and HAPA

Most of the articles in this review (66%) measured LAPA and HAPA. Among those that assessed LAPA and HAPA via self-report, most (93%) presented participants with positive emotion words on which to rate themselves. Sometimes validated scales were used, such as the Activation-Deactivation Adjective Checklist (Thayer, 1986), Affect Valuation Index (AVI; Tsai et al., 2006), Brief Mood Introspection Scale (BMIS; Mayer & Gaschke, 1988), Job-related Affective Well-being Scale (JAWS; Van Katwyk et al., 2000), or Positive and Negative Affect Schedule-Expanded Form (PANAS-X; Watson & Clark, 1994). More often, instead of a scale, representative emotions were assessed (see below for analysis of the positive emotion words used as items). Roughly 15% of the articles that measured LAPA and HAPA with positive items also included negative items, either reverse coded or as anchors for a negative to positive continuum. Less-used approaches to assessment involved rating valence and arousal separately (e.g., Self-Assessment Manikin [SAM], Bradley & Lang, 1994), or on an affect grid (e.g., Russell et al., 1989), and measures that present a series of statements (e.g., Howardson & Behrend, 2016). More rarely, physiological data were used to assess or validate arousal (e.g., Schwerdtfeger & Gerteis, 2014).

Items used to measure LAPA and HAPA

We identified the items used to measure LAPA and HAPA in 150 articles based on the authors reporting the exact items used, a representative sample of the items used, or a validated scale from which the items could be derived. Table 17 displays the frequency with which each item was used. Beyond reporting the frequency of items used to measure LAPA and HAPA, we offer observations about possible measurement problems and conceivable qualities of HAPA and LAPA that can be inferred from item usage.

Table 17 Frequency of use for items measuring HAPA and LAPA

Frequency of items used

For both LAPA and HAPA, two items were used more frequently than other items. For LAPA, researchers converged on calm and relaxed which were used in 82% and 67%, respectively, of articles that measured affect with positive items. For HAPA, less of a consensus was apparent for the top two items; excited was used in 56% and enthusiastic in 49% of papers measuring HAPA, and there was a wider range of positive words used to assess HAPA (52) compared to those used to assess LAPA (31). In the 21 articles using negative items, we did not observe a pattern in positive/negative pairs, but the most frequently reverse-coded or opposite anchor words were tense and worried for LAPA and bored and depressed for HAPA.

Possible concerns in item use

Regarding possible measurement problems, we noted four areas of concern. First, some items were used to measure both HAPA and LAPA with relative frequency. For example, the word happy was frequently used to assess HAPA and sometimes used to assess LAPA, as was cheerful. Such overlap suggests that researchers should consider avoiding these words as a measure of either LAPA or HAPA.

The second concern is related to the first; like happy and cheerful, the arousal level of some words used to measure either HAPA or LAPA can be considered ambiguous or in dispute. For example, satisfied or satisfaction was used 16 times to connote low arousal, and this comports with the conceptualization of some scholars (e.g., Russell, 1980) but not others (e.g., Tsai et al., 2006; Watson et al., 1999). In fact, Tsai’s conceptualization of satisfaction as MAP (medium arousal positive) is consistent with recent factor analyses that locate satisfied (along with happy, content, and pleased) within a moderate-arousal positive affect factor (MAPA; e.g., Longo, 2015), distinct from both LAPA and HAPA. We note that other items can also be seen as having ambiguous arousal levels such as interested (Tomkins, 1962), grateful (Kranzbühler et al., 2020), and wonder (Irrgang et al., 2016).

A third concern about the items used to measure LAPA and HAPA is the occasional use of words that may not actually be affect. For example, challenge is a characteristic of a situation (Nakamura & Csikszentmihalyi, 2002), talkative describes a specific behavior, responsibility is a phenomenon related to agency and choice (Frith, 2014), and optimism/pessimism are cognitive orientations (Bruininks & Malle, 2005).

Finally, only a few researchers reported English translations of the words they used in their research. For example, Madrid and Patterson (2014) provide their Spanish translations for calm (calmado[a]), relaxed (relajado[a]), laid‐back (distendido[a]), at ease (tranquilo[a]), enthusiastic (entusiasmado[a]), joyful (alegre), inspired (inspirado[a]), and active (activo[a]). Reporting translations is important, because the words used for emotions in any language shape the nuance of the experience (Barrett, 2017; Mesquita & Frijda, 1992; Russell et al., 1989), and the field should be afforded the opportunity to investigate and evaluate such nuances.

Indication of motivational intensity in item use

Our inspection of items used to assess LAPA and HAPA provided an initial indication that motivational intensity can be considered a quality that distinguishes LAPA from HAPA, and that characteristics related to approach and avoidance motivation can distinguish between different types of LAPA. Regarding HAPA, the item most used in its assessment (excitement) connotes high approach motivation, eagerness, appetite, and reward seeking. Other frequently used HAPA items could be argued to connote approach motivation (e.g., enthusiasm, inspired, interested), but many could not (e.g., joyful, elated, energetic). So, if we take item usage as an indicator of the underlying phenomenon, we must conclude that HAPA may often involve approach motivation, but not always.

However, when we reviewed the items used to assess LAPA, almost none connote approach motivation or suggest any future movement toward or away from anything (with the possible exception of the infrequently used “sensual” which could suggest moving toward sensual gratification). Furthermore, we observed that states that are often considered LAPA may encompass a steady state that is neither active nor reactive (calm) and two deactivating states that involve the fulfillment of a need or a desire (satisfaction) or the alleviation of pain or avoidance of a threat (relief). Calm was the most frequently used item for measuring LAPA, with 114 articles across all domains using calm in their LAPA assessment. Satisfaction was used less frequently, but still widely, across research domains, including development (e.g., Hudson et al., 2016), cardiovascular health (Armon et al., 2014; Neumann & Waldstein, 2001; Shirom et al., 2009), solitude (Lay et al., 2019), well-being (Collins et al., 2009; Jans-Beken et al., 2019), and work (Balducci et al., 2012; Kelloway et al., 2013; Urick et al., 2018). Relief was used primarily in research about non-suicidal self-injury (Claes et al., 2010; Di Pierro et al., 2014; Klonsky, 2009; Kranzler et al., 2018). Such observations indicate that LAPA can be conceptualized as involving neither approach nor avoidance in the moment in which it is experienced, though it may involve previously experienced approach or avoidance which was resolved with satisfaction or relief.

Ultimately, researchers are responsible for ensuring that their methodology is sound when manipulating and measuring constructs such as LAPA and HAPA, using measures that provide as much valid data as possible, while also considering whether their approaches are used by other researchers. As more clarity is brought to our understanding of LAPA and HAPA, the field should endorse highly valid items and manipulations and reject or qualify others.

Discussion

This review was motivated by indications that LAPA and HAPA are substantially different and that this difference is often overlooked. In other words, LAPA is not simply less of a good thing, but an altogether different kind of good thing. We reasoned that if LAPA is considerably different than HAPA, then we would expect to find that LAPA and HAPA have different relationships to varied phenomena. Therefore, our search and summarizing were animated by these questions: What evidence indicates that LAPA and HAPA have, or do not have, different causes, associations, and consequences? What characteristics of LAPA might help to explain such differences?

We found overwhelming evidence of differences between LAPA and HAPA across a wide range of research domains, with 89% of 226 articles comparing LAPA and HAPA indicating some kind of difference in their relationships to varied phenomena. See Table 18 for a summary of the most consistently found differences. Furthermore, we observed in these differences that the differentiating characteristics of LAPA and HAPA can often be seen as consistent with theory that integrates dimensions (valence/arousal, approach/avoidance) and functions (evolutionary, everyday) of emotion. Namely, Gilbert’s (2005, 2014) model of emotion delineates two types of positive affect, one that is associated with drive, desire, novelty, and achievement (HAPA) and one that is associated with soothing, rejuvenation, familiarity, and affiliation (LAPA). To shed additional light on LAPA and to point to future research directions, we now offer observations about LAPA and its role in human functioning, relating such observations to existing research on positive affect and emotion.

Table 18 Indications of differences between LAPA and HAPA

What is LAPA’s role in human functioning, distinct from HAPA?

As stated earlier, inclusion of LAPA in research on positive affect is increasing, but research focused specifically on LAPA’s distinction from HAPA is limited (Longo, 2015; Pressman et al., 2019). As such, the observations we make here should be seen as only a preliminary answer to this question. Here we focus on broader themes supported by consistent findings, avoiding single findings, mixed results, or data from areas that require specialization beyond our abilities.

LAPA as the soothing inverse of stress and anxiety

Consistent with Gilbert’s emphasis that LAPA serves a soothing function (2005, 2014) and Warr’s (1990) emphasis that contentment is the opposite of anxiety, and depression is the opposite of enthusiasm, the evidence for LAPA’s strong inverse relationship to anxiety and stress is indicated across multiple studies. Some studies find that HAPA and LAPA have similar relationships to these outcomes (Jiang, 2020; McManus et al., 2019), and some studies find that LAPA has a stronger relationship to them than HAPA (Gilbert et al., 2008; Kuan et al., 2018; Kuijsters et al., 2015), but no studies find that HAPA has a relationship to stress and/or anxiety when LAPA does not. Furthermore, the soothing function of LAPA is suggested by the results of research by Pressman and colleagues (2017), where state LAPA was associated with better sleep on days when stress levels were high and worse on days when stress levels were low. Such a finding suggests that LAPA is comforting in the face of stressful emotion.

LAPA’s opposition to stress may be particularly important to research on cardiovascular health. Cardiovascular health has long been associated negatively with stress and anxiety (Steptoe & Kivimäki, 2012), and LAPA has been found to have a more consistent advantageous relationship to cardiovascular health than has HAPA by some studies (e.g., Armon et al., 2014; Shirom et al., 2009). It may be that LAPA’s soothing impact on anxiety and stress could explain some of this relationship, however, more research is needed to support causal claims in this relationship. It is not known whether LAPA is a by-product of other circumstances that produce better cardiovascular health, or how LAPA may or may not impact these outcomes. For example, is it a function of valuing LAPA (Tsai, 2017) that motivates people to choose less stress-inducing contexts? Or could valuing LAPA cause people to interpret low-arousal situations as positive (Kuppens, 2008)? Can interventions for increasing LAPA have positive effects on cardiovascular health and other health indicators such as sleep?

Researchers should investigate LAPA’s role in the “undoing” effect, wherein positive affect has been found to help people recover from physiological stress responses (sympathetic activation) associated with negative emotion (Fredrickson et al., 2000). A recent meta-analysis has indicated that such an effect may be limited to cardiovascular reactivity (Behnke et al., 2022). Behnke and colleagues (2022) suggest that to understand the undoing effect of positive emotions, “it will be important to clarify whether and how enthusiasm might support the fast, active pursuit of tangible resources and how contentment might facilitate physical rest and digestion” (p. 55). We propose that the broader conceptualization of HAPA and LAPA may be useful in this effort.

LAPA at work: Psychological safety

We observed an interesting irony when interpreting the findings related to positive affect at work. The measure of affect used in much of work-related research, the Job-Related Affective Well-Being Scale (JAWS; Van Katwyk et al., 2000), was based on Warr’s model (1990), which is rooted in decidedly clinical terms (depression and anxiety). However, we consider Gilbert’s model a better fit for understanding behavior at work, even though it was proposed in a clinical context. Not only does Gilbert (2005, 2014) describe HAPA as having driving force, but he also includes aspects of feeling safe in his conceptualization of LAPA. The inclusion of feeling safe in conceptualizing LAPA is important, because it connects the concept to a large body of research on psychological safety at work (Edmondson, 1999; Edmondson & Lei, 2014). In this literature, psychological safety is a context in which team members feel free to share ideas and make mistakes without fear of reprisal.

The work-related findings reviewed here are consistent with a view of HAPA as driving and LAPA as signaling safety, and researchers should consider the complex relationship between LAPA and HAPA at work. Take, for example, the case of creativity. Even though much research in this review directly links HAPA and not LAPA to creativity (e.g., De Dreu et al., 2008; Hutton & Sundar, 2010), studies have consistently shown that psychological safety in teams promotes creativity (Edmondson & Lei, 2014). That LAPA signals psychological safety needs further study, since very few studies investigate psychological safety’s relationship to affectivity, and when they do, they tend to be oriented toward HAPA (e.g., Kark & Carmeli, 2009) or discrete emotion (e.g., Lee, 2021). Future research on positive affect at work should consider the aspects of HAPA that drive productivity, creativity, and innovation; at the same time, such research should consider the aspects of LAPA involved in the psychological safety that enables and sustains such creativity.

LAPA is especially associated with positive sociality

Looking across domains of research in this review, we observed a trend that LAPA’s relationship with positive sociality may be more consistent than HAPA’s. By positive sociality we mean a broad concept of beneficial interactions with other people, including supportive tone, affection, and positive relationships. For example, when participants viewed LAPA images during their log-in process, they were more sociable and positive in tone compared to participants who viewed no images (Seering et al., 2019). Among those with avoidant attachment (those for whom intimacy and closeness can be threatening), savoring a positive emotional relationship experience actually decreased their LAPA but not HAPA (Palmer & Gentzler, 2018). And people who score high on an empathetic personality test prefer LAPA music to HAPA music (Greenberg et al., 2015).

Such findings are consistent with Gilbert’s (2005, 2014) model of affect in which the soothing aspect of LAPA is associated with affiliation, care for others, and attachment. This model highlights findings that the neural substrates that are used to signal “liking” (Berridge & Winkielman, 2003) were recruited in our evolutionary need to develop care instincts for our mammalian offspring, along with cooperative problem-solving among our tribe. Recent research on mothers and infants is consistent with the proposition that social interaction engages the soothing function of LAPA. Cirelli et al. (2020) asked mothers to alternately sing a lullaby to infants in upbeat, exciting tones and calming, soothing tones while consistently monitoring skin conductivity to measure arousal. They found that arousal levels were not impacted by the exciting renditions, but arousal levels for both mother and infant decreased continuously as the soothing rendition progressed.

Research on LAPA and positive sociality should be integrated with discrete emotion research on the nature of love and the qualities of specific loving emotions. Take for example, Fredrickson’s (2013, 2016) conceptualization of love as positivity resonance, characterized by three components: shared positive affect, caring nonverbal synchrony, and biological synchrony (Zhou et al., 2022b). It is possible that moments of LAPA may be found to be more related to the experience of love than HAPA moments. In addition, LAPA’s role in prosocial behavior and attitudes (i.e., empathy) warrants further research (Telle & Pfister, 2016).

LAPA contributes to happiness and well-being

That LAPA plays an important role in happiness and well-being is especially apparent in cross-cultural research, even though it has often been overshadowed by HAPA in constructs emanating from Western cultures. For example, a widely used measure of subjective well-being measures life satisfaction, negative affect, and activated positive affect, without assessing LAPA (Diener et al., 2002). Additionally, within this review, the frequency with which happy is conflated with either HAPA or LAPA is revealing. Happy was used to measure HAPA eight times more frequently (33) than it was used to measure LAPA (4). Furthermore, nearly all of the research conflating HAPA with happiness occurred in North American or European countries (91%). And yet when samples around the globe are asked to describe well-being, they more frequently mention LAPA-related concepts than HAPA-related concepts (Delle Fave et al, 2016; Osei-Tutu et al., 2020). This is consistent with other research that has found that definitions of happiness in East Asian countries and cultures emphasize calm (Kitayama & Markus, 2000).

These findings should be considered in light of recent work on cultural differences in valuing positive affect (Tsai, 2017). Tsai’s research has found that people in Western cultures tend to value HAPA more than people in East Asian cultures and people in East Asian cultures tend to value LAPA more than people in Western cultures, though recent studies have found variations in these findings (e.g., Gui et al., 2020; Zhou et al., 2022a). This research indicates that happiness is greatest when people get more of the type of positive affect that their culture values. This preference for LAPA or HAPA has been found to relate to cultural differences in evaluations of politicians (Tsai et al., 2016), children’s books (Tsai et al., 2007), and doctor’s visits (Sims et al., 2014), among others. The finding that entire civilizations have come to value these two types of positive affect differently is important to consider when interpreting this review and contemplating future directions of research. Tsai’s fundamental insight, that affect can be valued differently, highlights that researchers should be aware of what type of affect they have been acculturated to value, and what type of affect they have been given to overlook. This review provides further support for this recommendation by demonstrating the different roles that HAPA and LAPA play in myriad aspects of life; if researchers overlook one in favor of the other, knowledge about happiness and well-being will be skewed.

Some scholars have addressed the potential for such a skewed assessment of well-being by introducing the Peace of Mind Scale (PoM), noting that it “reflects Chinese’ affective well-being, one that reflects the importance of LAP affect and mental harmony” (Lee et al., 2013, p. 573). Consequently, the PoM emphasizes different qualities of well-being than does the Satisfaction with Life Scale (SWLS: Diener et al., 1985). Though both scales contain several statements about one’s life, a contrast can be made between a sample item from the LAPA-inspired PoM (“The way I live brings me feelings of peace and comfort,” p. 585) and from the HAPA-inspired SWLS (“So far I have gotten the important things I want in life,” p. 72). Whereas the former connotes a self-contained sufficiency, the latter implies the culmination of acquisition. The contrast in these scales is a subtle but powerful example of the contrast between LAPA and HAPA, and the need to attend to their differences.

Indeed, detecting the value of LAPA as a contributor to well-being may be simply a matter of scratching the surface, even in Western cultures. For example, when happiness was framed with an emphasis on LAPA (satisfied) or HAPA (ecstatic), more Swedes rated themselves as happier when presented with the LAPA definition than the HAPA definition (Bjalkebring et al., 2015). Furthermore, when HAPA and LAPA were directly compared to “feeling good” over the past week in two U.S.-based studies (McManus et al., 2019), the correlation between LAPA and feeling good (r = 0.83, 0.83) was similar to the correlation between HAPA and feeling good (r = 0.79, 0.81). Indeed, when LAPA’s unique contribution to “feeling good” over the past week was assessed, it explained roughly 10% of the variance above and beyond HAPA, indicating that LAPA is an equal associate to the general sense of feeling good, and contributes to feeling good in its own unique way. Future research should consider both HAPA and LAPA in concepts of happiness and well-being, especially in light of recent research which found that across a variety of positive psychology interventions designed to increase well-being, LAPA was increased, but HAPA was not (Kraiss et al., 2023).

For whom is LAPA especially important?

LAPA and older adults

Robust evidence indicates that LAPA is experienced more by older adults than younger adults (e.g., English & Carstensen, 2014; Kessler & Staudinger, 2009; Ready et al., 2019). Many explanations for the relationship between LAPA and older adulthood have been put forth. For example, some researchers have postulated the age difference in LAPA is attributable to age-related cognitive decline (Bjalkebring et al., 2015), reduced physiological flexibility in older adults (Scheibe et al., 2013), a by-product of late-life events such as retirement (Hudson et al., 2016), an adaptive reaction to managing functional loss and stress (Kessler & Staudinger, 2009), or a shift in attention from the future toward the present (Carstensen, 2006; Mogilner et al., 2012). Additionally, these findings may be partially explained by an age-related increase in acceptance of negative affect (Shallcross et al., 2013). However, we observed that researchers tended to agree with English and Carstensen’s (2014) statement that “the reasons for such differences remain highly speculative and demands targeted investigation” (p. 8).

With such a wide array of possible explanations, we suggest that exploratory qualitative research is indicated, so as to allow for the emergence of unarticulated explanations and the possibility of complex relationships between causes. Here we offer two additional possible explanations. First, it is possible that a preference for LAPA is learned, through trial and error, and as adults age, they consciously choose more LAPA-inducing behavior because, in their experience, LAPA proved to be more rewarding. Second, another possible explanation could be related to the LAPA subtypes of satisfaction and relief. With desires fulfilled (or abandoned) and threats averted (or accommodated), the circumstances of life hold increasingly fewer things to move toward or against, because past approach and avoidance tendencies have been resolved. Such possibilities may be consistent with aspects of Charles’s (2010) Strength and Vulnerability Integration (SAVI) model of the development of emotional regulation and well-being across adulthood, which posits that older adults develop strategies for avoiding negative and arousing stimuli while maximizing positive emotional experiences. Future research should explore these possibilities, especially in light of efforts to understand positive aging (Nakamura & Chan, 2020).

LAPA and women

An unanticipated theme emerged from the studies comparing HAPA and LAPA across varied domains of research; differences between men and women were found, especially in terms of LAPA. For example, women’s experiencing less LAPA than men was mediated by socioeconomic factors, particularly having children, but lower levels of HAPA was not related to socioeconomic factors (Simon & Nath, 2004). LAPA images (family scenes and landscapes) were rated more pleasant by women than men (Gomez et al., 2013). For women, but not men, LAPA prior to game play predicted improved creative problem-solving during play of a computer game (Yeh et al., 2016). Following exercise, LAPA decreased cortisol levels to a greater degree for women than for men (Karageorghis et al., 2018). When mothers interact with infants, their style of play is more often characterized as LAPA, while fathers’ interaction with infants is more often characterized as HAPA (Feldman, 2003). When men reported more LAPA at work, levels of good cholesterol were higher and triglycerides were lower, but this relationship was not observed in women (Shirom et al., 2009). These findings of gender differences are consistent with research on ideal affect where it was found that men and women experienced LAPA more than HAPA during leisure, but neither experienced as much HAPA as they desired, and only women did not experience as much LAPA as they desired (Mannell et al., 2014).

Do these associations mean that LAPA is a woman’s emotion? We think not. Rather, it may be that cultural practices may cause women to experience demands and deprivations that men do not, and such experiences may make LAPA less attainable in women’s daily life, and therefore more precious. Indeed, symbols of calm and relaxation are used in advertising and media targeted to women to signal a kind of ultimate luxury. For example, women-targeted smartphone apps promise to induce calm, magazines celebrate simplicity, and products are linked to the cozy feeling of hygge (Altman, 2016; Raphael, 2019; Rose, 2000). More research is needed to investigate gender-related differences in LAPA.

Investigating other moderating factors

Very few of the articles reviewed here investigated other potentially important moderating factors such as race, where lower levels of positive affect especially HAPA were found among African American and Asian youth compared to White youth (Deer et al., 2018), or socioeconomic status, where social status mediated the lower levels of LAPA in women (Simon & Nath, 2004). As emotion researchers attend to social injustice (Cropanzano et al., 2011; Rimke, 2016), these factors and others that may impact positive affect should be investigated. Such moderating factors could potentially include childhood trauma (DePierro et al., 2018), family structure (Barden et al., 2016), encounters with law enforcement (Barkworth & Murphy, 2015), housing status (Labella et al., 2023), and immigration status (Alivernini et al., 2019).

What characterizes LAPA, beyond positive valence and low arousal?

We include in this discussion observations about characteristics of LAPA, because we hope to provide researchers with tools for paying more attention to it. The nature of low arousal emotion is that it does not demand the attention of those who experience it (Berridge & Winkielman, 2003), and if it is not valued, it is even more difficult to detect. People are less likely to remark on and share emotion when it is lower arousal (Rimé et al., 1992). When everyday language use does not take notice of positive low arousal, it can make recognition of these states less likely (Barrett, 2017). The characteristics of LAPA described here can provide clues for its detection in everyday life as well as novel approaches for its inclusion in research.

LAPA is rooted in the present moment

One of the more intriguing findings in this review is the contrast between LAPA and HAPA in terms of time orientation; LAPA was found to be associated with a focus on the present moment, while HAPA was found to be associated with an orientation toward the future (Mogilner et al., 2011, 2012). This finding is somewhat surprising in light of research that links the savoring technique of focusing on the present moment to an increase in HAPA (Quoidbach et al., 2010), but in that research, there was no assessment of LAPA, so a comparison between HAPA and LAPA was not possible. The association between the present moment and LAPA may help to explain the evidence that LAPA is increased by mindfulness interventions when HAPA is not (e.g., Imtiaz et al., 2018; Zeng et al., 2019). Turning the attention toward the present moment is a core aspect of mindfulness practice, which involves monitoring what is happening in the inner and outer world at the present moment with acceptance and non-judgement (Lindsay & Creswell, 2019; Teper & Inzlicht, 2013), and this acceptance of the present moment may be key to understanding why LAPA is associated with mindfulness more so than HAPA. As will be discussed in the next subsection, LAPA itself may be characterized by accepting the present moment, and what came immediately before without wanting more or less of what is present.

LAPA as the resolution of approach-avoidance motivation

In this section we explore a way of conceptualizing low arousal positive states in terms of their relationship to approach and avoidance. As mentioned earlier in our analysis of items used to measure HAPA and LAPA (see Table 17), we looked for words that indicated approach motivation in each type of affect. We observed that the vast majority of items used to measure LAPA connoted no approach motivation in the present moment. In fact, we observed three subtypes of LAPA based on whether and when approach-avoidance was implied (calm, satisfaction, relief). These three possible subtypes can be considered similar in terms of arousal level and positivity, but they differ in terms of the conditions implied by them: a steady state of neither approach nor avoidance (calm), having approached and attained something wanted or needed (satisfaction), and having avoided or stopped something unwanted (relief).

Calm, the most-used item, could be considered a no-motion emotion, in that it suggests moving neither toward nor away from any experience. It implies stability of mind and ease within the body in which there are minimal (or manageable) external and internal demands. In contrast to calm, which implies a steady state, the other two subtypes of LAPA, satisfaction and relief, indicate movement, a shift from a prior state, where emotional arousal had been elevated in response to desire or threat. To be relieved is to have shifted away from a negative experience (the resolution of avoidance), and to be satisfied is to have shifted toward the attainment of a desired experience (the resolution of approach). Both of these states may involve deactivation, or diminishing arousal, but they are not entirely explained by arousal, because this decreased arousal results from goal achievement (satisfaction) or threat aversion/pain alleviation (relief). Even though some emotion researchers have noted that positive states such as joy and contentment call forth inaction (Frijda, 1986; Tugade et al., 2014), the importance of such inaction has not been fully explored.

We cannot overstate the importance of the observation that a critical component of feeling good involves moments of no-approach and no-avoidance. We believe that recognizing the low-arousal and deactivating goodness of wanting nothing, needing nothing, or fixing nothing, is akin to mathematicians discovering zero. It is a concept, hiding in plain sight, that could illuminate myriad emotional processes associated with development, health, mental health, and well-being, empowering practitioners and laypeople to solve otherwise unsolvable emotional equations.

LAPA conceptualized as an optimal homeostasis

We offer a final observation about LAPA, consistent with the increased attention to and promotion of LAPA. We suggest that LAPA can be conceptualized as a kind of optimal homeostasis, the condition of balance and stability to which a system returns to as it dynamically adjusts to the demands of its environment. This view of LAPA comports with the concept of a homeostatically protected mood, which Cummins (2016) describes as a nonconscious, unreflective, resting state which “is best reflected as a general feeling of contentment, but also comprises aspects of related affects including happy and alert” (p. 63). This perspective can be considered in light of a number of other views on emotion, including the neurologic meta-stability of liking and wanting (Kringelbach & Berridge, 2017), a dynamic systems perspective on emotion regulation (Fogel et al., 1992; Thompson, 2011), the “coasting” response to positive affect (Carver, 2003, p. 243), emotional equilibrium across the lifespan (Labouvie-Vief, 2015), hedonic set-point (Fujita & Diener, 2005), and the positivity offset, or the tendency for people to interpret neutral, low-arousal circumstances as positive (Cacioppo & Berntson, 1999; Diener et al., 2015).

A key consideration here is that any affective state exists in relationship to other emotions and how they unfold over time. For example, in describing emotion dynamics, Kuppens and Verduyn (2017) highlight the importance of studying processes associated with one emotion predicting another emotion across time. We propose that LAPA may have a particularly central relationship to other affective experiences. It may serve as a kind of home base which affective experience departs from and returns to – a state of satiety and pleasantness which fosters restoration and rejuvenation. It may be the state to which all other emotions are attached – the systemic safe haven from the demands of arousal, and the secure base from which to rise to meet those demands. If the emotional system continually returns to this central, pleasant low-arousal state, then more time spent in LAPA may signal a healthier emotional system. Researchers could investigate the sequential relationship of LAPA to other desirable and undesirable emotions and life outcomes to explore the possibility that LAPA is a particularly potent signal of optimal human functioning.

Limitations

Among the most significant limitations of this paper is that despite (or perhaps because of) our systematic approach to searching and selecting articles, this review might not have yielded all of the findings related to LAPA and HAPA. Although we used an expansive range of search terms, examining thousands of articles, our exclusion of papers that did not conceptualize affect in terms of arousal may have left out some conceivably relevant papers. For example, this criterion led to the exclusion of research on the discrete emotions of contentment and pride (Griskevicius et al., 2010) and awe (Shiota et al., 2011), as well as research on approach motivation investigating calm and excitement (e.g., Gable & Harmon-Jones, 2008). Similarly, our exclusion of research on the large body of work involving ideal affect and differences in cultural valuation of affect (e.g., Tsai, 2017), leaves much remaining to be said about LAPA and HAPA in such contexts. We excluded several unpublished papers (e.g., theses and dissertations) that would have otherwise met our criteria, suggesting that the universe of comparisons between LAPA and HAPA is expanding, and that even at the completion of this paper, the story it tells will be incomplete.

An additional limitation involves negative affect; many of the studies in this review researched HAPA and LAPA in order to detect differences or interactions in the effect of valence and arousal and included high- and low-arousal negative affect as variables in their experiments. As such, when positive affect is contrasted with negative affect, there may be a pattern of effects that we did not look for. Finally, the variability in the conceptualization, operationalization, and manipulation of HAPA and LAPA should be considered a limitation of the findings reported here; given that the operational distinction between HAPA and LAPA is sometimes blurry, the findings of such studies should be interpreted with caution. To be sure, shedding light on the status of LAPA and HAPA operationalizations was a strong motivation for conducting this review.

Conclusion

This review provides strong evidence that the two types of positive affect, LAPA and HAPA, are similar in positivity but have different associations across a wide variety of domains, most notably adult development, mindfulness, creativity, exercise, brain activity, and cardiovascular health. We observed that many of these differences fit with theory that associates HAPA with drive and LAPA with soothing and affiliation (e.g., Gilbert, 2005; Tomkins, 1962) and suggest that such a pattern of findings warrants direct investigation. Additionally, conceptualizations of LAPA should incorporate the positive qualities of no-approach/no-avoidance, along with the circumstance of such a state, whether it is due to a steady state of calm, the recent satisfaction of desire, or the removal of something not wanted. Furthermore, the relationships of LAPA to well-being, stress, work, positive sociality, older adults, and women warrant further investigation. Researchers, practitioners, and laypeople should be aware of the distinctions between LAPA and HAPA in terms of their causes, consequences, and associations, because the consideration of these distinctions can help in discovering and deploying effective approaches to optimizing human functioning.