Indisputably, humans are social beings, who need to form and maintain fulfilling relationships with others (e.g., Baumeister & Leary, 1995). At the same time, people vary tremendously in how they maintain social relationships: Some people have very large social networks and frequent contact with many different people, others focus on a few close friends (e.g., Harris & Vazire, 2016; Wrzus et al., 2013). Some people like being with others permanently, while others seek solitude more often (e.g., Coplan et al., 2019; Nestler et al., 2011). Thus, with whom and how quickly social needs are satisfied or deprived varies strongly between people and also within people over time. Still, these variations or dynamics across relationships and time are hardly understood because the majority of relationship research in adulthood focuses on single relationship categories (e.g., friends, romantic partners, or parent-child dyads) and rather static relationship aspects (e.g., the number or quality of friends; for reviews, see Harris & Vazire, 2016; Vangelisti & Perlman, 2018).

The current study thus addresses two aims: As part 1, we conceptualize three different aspects of social dynamics, link these aspects to related, established interpersonal dispositions as well as develop and validate a questionnaire to measure social dynamics across relationships and time. We distinguish three aspects of such social dynamics: (a) Family-friends interdependence, (b) Social deprivation, and (c) Social oversatiation (Fig. 1). For the validation, we also examine associations between social dynamics and other personality dispositions. As part 2, we examine whether the novel measure on social dynamics can indeed predict changes in contact across time and in different social relationships.

Social dynamics concern the interdependencies across different relationships and across time as people’s social interactions are a continuous flow of time alone and time in contact with different people (Luo et al., 2022). Consider a theoretical example, where a college student living with a partner has breakfast with the partner before driving to class alone and then meeting fellow students. After class, the student spends some time alone before visiting the grandparents for dinner. After dinner, the student goes to work in a restaurant and meets colleagues as well as guests before returning home to the romantic partner. Although these social interactions seemingly constitute singular encounters, they are often linked—both across relationship types and across time. Whether the student visits family or spends more time with friends in the afternoon depends on whether friends or family are more important (Wrzus et al., 2011)—in addition to other factors, such as who has time or needs support (Nezlek, 2001). In addition, if time is spent with one group (e.g., family) this time is generally not spent with others (except in rare cases of contacts with multiple relationship types, Wrzus et al., 2016). Furthermore, the amount and quality of earlier social contact, e.g., with friends during and in-between classes, can affect whether a person seeks further contact or some time alone (e.g., Luo et al., 2022).

The described interdependencies across different relationships and across time partly result from people’s affiliation motive (for an overview see Hofer & Hagemeyer, 2018). A brief definition of the affiliation motive is that people possess an innate need to form and maintain social relationships (Deci & Ryan, 2000; Hofer & Hagemeyer, 2018). Satisfaction or deprivation of affiliative needs in social interactions can occur in different relationships (e.g., friends, family, romantic partner) and elicits affective experiences, which in turn stimulate future behavior towards need satisfaction (Baumeister & Leary, 1995; Neubauer et al., 2018; Sheldon, 2011). Thus, when interactions in social relationships are not considered as singular instances but rather as continuous dynamic of time alone and interactions with different people, these social dynamic can be described regarding linkages across relationships and across time (Fig. 1). Next, we explain both aspects in more detail.

Fig. 1
figure 1

Conceptual visualization of central terms of social dynamics. Note The concepts can be seen as both dynamically changing within-person processes and individual differences between persons in such social processes. As explained in the text, dynamics across relationships always occur also across time and dynamics across time often occur also across relationships. Furthermore, the current study focused on Family-friends interdependence, Social oversatiation, and Social deprivation. During the review process it became apparent that other interdependencies across relationships likely exist as well, e.g., between romantic partners and friends (e.g., Fiori et al., 2017), between (in-law) family and romantic partners (e.g., Bryant et al., 2001)

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Social dynamics across relationships

Theories on the affiliation motive agree that the need for forming and maintaining social relationships can be satisfied, albeit to various extents, in different forms of relationships during adulthood such as family relationships, friendships, or romantic relationships (for a review, see Hofer & Hagemeyer, 2018). Accordingly, research on social networks, that is, the entirety of social relationships people maintain, demonstrates that diverse relationships “coexist” within individuals, and most people maintain relationships from different relationship types, such as family members, romantic partners, as well as non-relatives (Mund & Neyer, 2014; Neyer et al., 2011; Wrzus et al., 2013). Family refers to biologically or legally-related relatives (i.e., in-laws), and thus could be (grand)parents, siblings, (grand-)children, and other more distant relatives (Neyer et al., 2011). Romantic partners and non-relatives such as friends are non-kin, that is, biologically unrelated and not legally regulated, except for spousal relationships (Neyer et al., 2011).

The majority of research on individual differences in adult social relationships focuses on specific relationship types separately, such as friends, romantic partners, or parent-child dyads (for reviews, see Harris & Vazire, 2016; Rözer et al., 2016; Wrzus & Neyer, 2016; for noticeable exceptions in adolescence see Gadassi Polack et al., 2021; Miller-Slough & Dunsmore, 2019, 2023). Such research omits that people generally maintain a multitude of relationships simultaneously, which can influence each other. As people are limited in their amount of time and energy, spending time with and taking care of some relationships usually leads to less available time and energy for others (Hall & Davis, 2017). Accordingly, interdependencies across relationships can be expected (Fiori et al., 2017; Gadassi Polack et al., 2021; Klärner et al., 2016; Rözer et al., 2016; Wrzus et al., 2012).

Interdependencies across relationships were reliably observed with respect to the existence and importance of certain social relationships: For example, people who reported fewer family members in their personal network named relatively more friends and vice versa (Rözer et al., 2016; Wrzus et al., 2012). Also, feeling less close to family was associated with relatively higher emotional closeness with friends and vice versa (Wrzus et al., 2012). Similarly, some people maintain friends-focused networks, whereas others’ networks mainly consist of family members or a mix (Fiori et al., 2007). Such differences in importance or closeness of friends vs. family might partly result from a stronger personal preference and thus a tendency to invest more into one or the other.

Results on the interdependence of maintaining contact with friends or family are mixed though: In one experience-sampling study with older adults, the relative frequency of contact with family was lower with higher relative contact frequency with friends in daily life (Müller et al., 2019), whereas no significant association was observed in a larger experience-sampling study (Buijs et al., 2023) as well as in average retrospective reports of contact with family and friends (Wrzus et al., 2012). The inconsistencies in results on contact might partly arise from external constraints and demands (e.g., available time, others’ expectations on contact), which were not measured in any of the studies. Such external demands could necessitate contact with some people despite having a preference for other people or for no contact.

Consistent with previous work (Fiori et al., 2007; Müller et al., 2019; Wrzus et al., 2012), we assume that people have a relatively stable preference for family, friends, or both similarly. To the extent that relationships with family and friends are interdependent, investing heavily into the one will leave less resources for the other (except perhaps in adolescence, Gadassi Polack et al., 2021). We assume Family-friends interdependence (FFI) to be a dimensional construct with exclusive focus on family or friends on either ends and varying degrees of preference for one or the other in between (see Fiori et al., 2007 for a categorial approach).

Social dynamics across time

In addition to social relationships being dynamically linked across different relationships, each specific relationship is inherently dynamic across time. That is, relationships vary and change over days, weeks, and months—both in quantity and quality (e.g., Hall, 2017; Sun et al., 2019). For example, contact with family and friends varies approximately as much within and across days as between individuals (Weber et al., 2020; Wrzus et al., 2016). Thus, assessing only average contact frequency or quality can overlook important aspects of social relationships: For example, of two individuals with similar average contact, one might have relatively regular contact, whereas the other bounces between times of too much and too little contact with potentially detrimental effects on well-being (Luo et al., 2022).

Theories that view affiliation motives as a central factor in the dynamic regulation of social interactions strongly emphasize the temporal aspects of social interactions and social relationships (e.g., Bischof, 1993; Hall & Davis, 2017; O’Connor, & Rosenblood, 1996; Sheldon, 2011). Such theories postulate that people possess an individually varying ideal level of social contact and closeness (i.e., the strength of the affiliation motive). Furthermore, people appraise daily situations regarding how well the actual social experiences fulfill their ideal level. In cases of Social deprivation, that is, when actual experiences do not fulfill the ideal level, or Social oversatiation, that is, when actual experiences exceed the ideal level, the individual is motivated to change the social experience through seeking or avoiding social contact (Bischof, 1993; Hofer & Hagemeyer, 2018; Sheldon, 2011). Empirical work hardly examined regulatory processes in social relationships, and instead focused on static snapshots of relationships (e.g., momentary number, contact, or quality of friendships and family relationships; Harris & Vazire, 2016; Neyer et al., 2011; Wrzus et al., 2013, 2016).

In addition to long-term changes (for reviews Blieszner, 2018; Harris & Vazire, 2016), relationships also vary from hour to hour, from day to day, and week to week. For example, people with higher extraversion and lower neuroticism are less likely to remain alone over the next two hours in daily life; instead, they reported more often being with friends, colleagues, or other people two hours later (Wrzus et al., 2016). These findings match experimental research, which demonstrates immediate effects of unsatisfied affiliation motives on seeking social contact (e.g., Maner et al., 2007). Similarly in romantic partnerships, stronger momentary motivation to be close to one’s partner predicted more positive interactions with the partner over the next hours (Zygar et al., 2018). In line with affiliation motive theories, more intense positive contact with partners when people wanted to be with partners was associated with better mood and higher relationship satisfaction, which indicates need fulfillment (Zygar et al., 2018). Surprisingly, people reported being still motivated for further contact with their partner after intense contact with their partner (Zygar et al., 2018)—perhaps needs were satiated, but not oversatiated to the extent that people wanted to be alone.

Other experience sampling studies, which did not focus on couples or distinguish relationship persons, also failed to demonstrate links between previous contact and momentary (motivation for) contact (Hall, 2017; Neubauer et al., 2018). Still, a greater desire to be alone predicted less future social contact (Hall, 2017). Inconsistencies in results regarding the coupling of previous and momentary contact might be due to examining temporal links only over a few hours within days. Perhaps more time has to pass before need oversatiation occurs and people (can) decrease contact.

In summary, social contact varies within individuals across time in quantity and quality. This variation might partly be due to existing opportunities (i.e., other people being available to engage in contact with or accessible places to be alone) and also individuals’ efforts to satisfy their affiliative needs, which differ as well between individual: Satisfaction of affiliative needs can occur through increases in contact in cases of Social deprivation and decreases in contact in cases of Social oversatiation. Such dynamics across time could be assessed in daily life, for example, using ecological momentary assessments or mobile sensing (Krämer et al., 2023) or in generalized questionnaires describing such dynamics, an approach chosen for the current study. The assumption behind this approach is that relevant differences between people in average patterns of dynamic daily-life social behaviours manifest over time in the self-concept similar to other generalized self-reports of behaviors or thoughts (i.e., personality questionnaires). Measuring these individual differences in social dynamics could offer an economical approach to study social dynamics when ecological momentary assessments or mobile sensing are too demanding.

Relation to other interpersonal dispositions

This section highlights similarities and differences of individual differences in social dynamics from other interpersonal dispositions, such as the affiliation motive and related need dispositions, social anxiety, and broad Big Five traits to demonstrate the necessity of separately measuring social dynamics.

Affiliation motive and related dispositions

Several interpersonal characteristics describe people’s stable tendencies to engage in and maintain social relationships and this section provides a brief overview: Affiliation Motive, that is, the need to form and maintain close, satisfying social relationships, contains several aspects (Hofer & Hagemeyer, 2018; Schönbrodt & Gerstenberg, 2012). Some researchers further distinguish an Intimacy Motive, which focuses on positive, approach-oriented aspects of close social relationships, from avoidance-oriented aspects of the affiliation motive that focus on the Fear of Rejection, that is, losing social connection in general (for reviews see Hofer & Hagemeyer, 2018; Schönbrodt & Gerstenberg, 2012). The Need to Belong (Baumeister & Leary, 1995) also refers to individual differences in the need to form and maintain social relationships and integrates aspects of social contact as well as feelings of belonging into one concept. Empirically, with higher affiliation motive, people also report a higher need to belong, and higher Sociability (i.e., a facet of Extraversion; Leary et al., 2013; Schönbrodt & Gerstenberg, 2012). Theoretically, with a higher Need to Belong, people should dislike being alone often, while empirically, the Need to Belong was only weakly related to the Need to be Alone and to do things alone (Leary et al., 2013; Nestler et al., 2011), perhaps because both needs can co-occur in individuals and are satisfied at distinct times.

In summary, most contemporary conceptualizations and measurements view the affiliation motive as a superordinate construct with aspects oriented towards initiating and maintaining social interactions (e.g., affiliation, need to belong) as well as aspects oriented towards reducing social interactions (e.g., need to be alone). As the affiliation motive can be satisfied in diverse close relationships such as family, romantic partners, or friends (for review Hofer & Hagemeyer, 2018), we do not assume associations with Family-friends interdependence. Instead, we assume that people with a higher general affiliation motive and also higher need to belong will experience more Social deprivation because it is more difficult to meet the stronger need for social contact most of the time. In contrast, we assume that people with a greater need to be alone and lower affiliation motive will experience Social oversatiation more often because unwanted social interactions might occur more often.

Social anxiety

Social anxiety describes feelings of unease and fear when interacting with strangers and less familiar people (Peters et al., 2012). Extreme levels are considered a specific anxiety disorder (i.e., social anxiety disorder), whereas low to moderate levels are reported for the general population (Peters et al., 2012). Conceptually, the strength of the affiliation motive and the level of social anxiety are distinct. For example, people with strong affiliation motive and simultaneously strong social anxiety (i.e. fear of rejection, Asendorpf, 1990; Poole et al., 2017) are often described as shy. In contrast, sociable people also possess a strong affiliation motive, yet do not or only hardly experience social anxiety. Empirically, social anxiety was also only weakly associated with affiliation motive and need to belong in the general population (Leary et al., 2013; Schönbrodt & Gerstenberg, 2012). As social anxiety mainly manifests in interactions with unknown and less familiar people (Asendorpf, 1990; Poole et al., 2017), one could assume that people with higher values in social anxiety have a stronger preference for being with familiar family. At the same time, close friends can be family-like (Buijs et al., 2023; Wrzus et al., 2012), and we thus expect weak associations between social anxiety and Family-friends interdependence. Given the weak association between social anxiety and affiliation motive, we expect Social oversatiation and Social deprivation (i.e., mismatches between the affiliation motive and social experiences) to also show only weak associations with social anxiety.

Big Five traits

Big Five personality traits are assumed to broadly summarize patterns of human behavior, with extraversion and agreeableness being central to interpersonal behavior (DeYoung et al., 2013; McCrae & Costa, 2008). Associations between Big Five traits and the preference for family over friends (or vice versa) can be inferred only indirectly from previous work. With higher values of extraversion, people have larger friendship networks, spend more time with friends, and report higher quality of friendships (e.g., Harris & Vazire, 2016; Selfhout et al., 2010; Wagner et al., 2014; Wrzus et al., 2016). Also, with higher values in agreeableness, people get along better with others, which results in high popularity and larger social networks (Harris & Vazire, 2016; Selfhout et al., 2010; Wagner et al., 2014). As people invest slightly more time in friendships with higher agreeableness (Wrzus et al., 2016), this could come at the cost of family relationships. However, empirically, agreeableness was not meaningfully associated with the frequency of being with either family or friends (Mueller et al., 2019; Wrzus et al., 2016, but see Buijs et al., 2023). Yet, measures of being with specific people, that is, friends or family, might only partly reflect a preference for one or the other as external constraints might enforce or restrict contact (Buijs et al., 2023). Given the inconsistent findings, we assume that, if at all, only weak associations between Big Five traits and Family-friends interdependence exist.

From a conceptual point, specifically the extraversion facets Sociability and Energy as well as the facet Compassion of the trait agreeableness should be closely linked to the affiliation motive and the quantity of social interactions (DeYoung et al., 2013; Leary et al., 2013). Extraversion as a broad trait additionally captures Assertiveness, and agreeableness also captures politeness, which refer more strongly to the quality of the interactions instead of the quantity (DeYoung et al., 2013; Soto & John, 2017). Thus in contrast to specific facet effects, we expect relatively low associations of the broad trait levels with Social deprivation and Social oversatiation. We expect no substantial association of Social deprivation and Social oversatiation with the other traits, that is, neuroticism, conscientiousness, and open-mindedness.

Current study

The current longitudinal study pursues two aims. The first research question in part 1 aims at developing a brief self-report questionnaire of social dynamics, the Social Dynamics Scale (SDS), to measure individual differences in (a) Family-friends interdependence, (b) Social oversatiation, and (c) Social deprivation. The second question in part 2 aims at examining the predictive validity of the Social Dynamics Scale, that is, whether the new measure can indeed predict changes in social contact across time and in different social relationships. Previous questionnaires assessing affiliation motive, the need to belong, or extraversion are relationship-unspecific and focus on social needs and social behavior. However, theses questionnaires do not address interdependencies across relationship types or consequences of unmet social needs. The Social Dynamics Scale is supposed to fill this gap. Next, we summarize the hypotheses outlined throughout the theoretical background.

Research question 1 and hypotheses on scale development

Research question 1 examines whether it is possible to measure individual differences in social dynamics reliably and validly. This part 1 focuses on the item selection, internal, and retest reliability, as well as factorial, divergent, and convergent validity of measuring social dynamics. To determine which of the newly developed items were best suited to measure social dynamics, we followed standard conventions for scale development (Boateng et al., 2018). We thus examined item difficulty, item variance, and interitem correlation. Proceeding from the theoretical background regarding the dynamic regulation to satisfy people’s affiliation motives (e.g., Hall et al., 2017; Hofer & Hagemeyer, 2018), we derived the following preregistered hypotheses (https://doi.org/10.17605/OSF.IO/N8JRV).

H1a: We assumed that social dynamics can be described in three subscales: Family-friends interdependence (FFI), Social oversatiation (SOS), and Social deprivation (SOD). Social oversatiation and Social deprivation are assumed to be weakly to moderately negatively correlated. FFI (scored towards friends) and Social deprivation are assumed to be weakly positively correlated, whereas FFI (scored towards friends) and Social oversatiation are assumed to be weakly negatively correlated.

H1b: We expected convergent validity, that is, moderate positive correlations between Social deprivation and affiliation motives, as well as between Social oversatiation and need to be alone.

Based on theoretical definitions of Big Five traits and social anxiety (e.g., Asendorpf, 1990; DeYoung et al., 2013; McCrae & Costa, 2008; Poole et al., 2017), we expected:

H1c: We expected divergent validity for all three subscales, that is, little overlap, with Big Five traits and social anxiety.

We did not preregister a separate hypothesis regarding the temporal stability, yet assumed that individual differences in social dynamics are similarly stable over several weeks—as indicated through retest correlations—as other personality constructs for adult populations (for a review, see Soto & John, 2017) because (a) social networks are relatively stable (Mund & Neyer, 2014; Wagner et al., 2014) and (b) individual differences in affiliation motive are rather stable (Fraley & Roberts, 2005), contributing to stable individual differences in deprivation or oversatiation.

Research question 2 and hypotheses on predicting changes in social contact across time

The second longitudinal part of the study utilized the social distancing rules during the first wave of the COVID-19 outbreak in Germany in spring 2020. The nationwide restrictions in social contact (Fig. 2) can be seen as an environmental factor inducing Social deprivation, with the opportunity to study as Research Question 2 how individual differences in Social deprivation predict subsequent changes in social contact when contact restrictions were progressively loosened. The data collection started on April 6th, when schools, restaurants, public facilities (e.g., gyms, theaters), and most shops were closed, and reoccurred every three weeks until June 14th, 2020, when most facilities were open again (see Procedure section and Fig. 2). Data collection was conducted online due to contact restrictions.

As described in the theoretical background, if (high) affiliation motives are not satisfied in social interactions, Social deprivation occurs, and people are motivated to change the dissatisfying states and seek social contact (Bischof, 1993; Hall, 2017). Accordingly, we assumed that after restrictions of social contact, contact would increase more strongly over time for people generally higher in Social deprivation (H2a). Similarly, when people are rather satisfied with low levels of social contact, they will delay seeking further social contact (Bischof, 1993; Hall, 2017). Thus, we expected that after restrictions social contact would increase less over time for people generally higher in Social oversatiation (H2b).Footnote 1

During national contact restrictions due to the COVID-19 pandemic, missing personal contact might be partly compensated for through indirect contact (e.g., messaging, calling). We did not explicitly preregister hypotheses specifically for indirect contact and explored associations with general Social deprivation and Social oversatiation.

Methods

Open science information

Following open science guidelines, we transparently report the determination of the sample size, assessed variables, further articles using the same data sets, exclusion of data, as well as adjustment of outliers (none), and its effects on the analyses. Our preregistered a priori power estimation based on a repeated-measures approach with α = 0.05, power = 0.90, and effect size f = 0.10 suggested assessing at least 195 people. The preregistration of hypotheses, documentation of assessed variables, as well as data used in the analyses, scripts, and outputs of data analyses are available on https://osf.io/8xubm. Data on social contact have been used to examine a distinct research question regarding associations with well-being (Krämer et al., 2022).

Participants

Through the survey agency www.clickworker.de we recruited 300 participants stratified across gender and five age groups (18–29, 30–39, 40–49, 50–59, and 60–75 years), of which 280 participants provided valid data (see Fig. 2). These participants ranged in age from 19 to 75 years (M = 45.2, SD = 14.3, 53% men). The majority of participants (66%) were married or in a stable romantic relationship, the remaining participants were single (25%), divorced (7%), or widowed (2%), and 41% of participants had children (number of children M = 1.79, SD = 0.83). Regarding completed education, 42% held a college/university degree, 29% had completed high school, and 28% had completed other schools. The majority of participants (41%) were working full-time, 19% were self-employed, 11% were students, 11% were working part-time, 9% were retired, and the remaining participants were unemployed or did not indicate their occupational status. The participants were diverse with regard to residential region in Germany and size of hometown.

At the end of the first assessment, participants could opt in to the longitudinal part of the study with three additional assessment waves. For the last assessment, we recruited 202 additional participants to boost the sample size. Figure 2 depicts participation rates and data exclusion over the four assessment waves.

Fig. 2
figure 2

Sample size flow and contact restrictions. Note The displayed dates refer to the activation of the online surveys. Participants had up to five days to answer after activation of the surveys. Participants were excluded if their response times indicated speeding, they showed unusual response patterns, or if they did not provide a valid identifier for follow-up (see section on Data Exclusion)

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Procedure

Participants answered four online surveys with approximately three weeks between surveys. The survey periods were chosen to reflect the gradual easing of social contact restrictions, which existed in 2020 to manage the COVID-19 pandemic. The strictest social-distancing regulations were in place at T1 when schools and most shops were closed, and severe restrictions regarding social contact existed. At T2, the social-distancing regulations were still very strict, but most shops were allowed to reopen. Social-distancing rules continued to be gradually loosened during the following weeks at T3 and T4 (Fig. 2). During each assessment wave, the surveys were available for five days to achieve similar assessment periods. Most participants (79% average across waves) answered the surveys on the same days that they were activated. All participants gave informed consent before answering the survey questions. The study was exempt from IRB approval because it focused on healthy, mature participants, assessed uncritical content, which was fully explained to participants, and followed the Helsinki declaration for treatments of participants. Participants received €4.50 for each of the first three surveys and €5.00 for answering the last survey.

Measures

We describe the measures used to answer the research questions and examined in subsequent analyses. A complete documentation of all variables assessed in the project is available on https://osf.io/8xubm.

Social dynamics scale (SDS)

Based on the theoretical considerations outlined in the introduction, we developed items for the three SDS subscales using a rationale, inductive construction approach (Bühner, 2011). The items described past behavior (e.g., “After spending all day alone…”) and self-concept aspects (e.g., “I am…”) and followed the current suggestions for item construction (Bühner, 2011). We pretested the items in small focus groups and removed ambiguities in phrasing. The initial item pool consisted of 39 items, which were assessed at the first assessment: 14 items for Family-friends interdependence, 11 items for Social oversatiation, and 14 items for Social deprivation. Table 1 reports the final item set after item selection (see Results section Part 1: Item Selection; see Supplementary Table S1 for complete list of German items and English translation). During the data collection, items were answered on a 7-point Likert scale with 1 = not at all and 7 = completely as anchors.

Affiliation motive and fear of rejection

Affiliation motive and fear of rejection were assessed using the short affiliation motive subscale and the items from the “fear of rejection” facet of the Unified Motive Scale (Schönbrodt & Gerstenberg, 2012). Sample items include “I try to be in the company of friends as much as possible” for affiliation motive and “When I get to know new people, I often fear being rejected by them” for fear of rejection. The Unified Motive Scale includes items formulated as statements, which require an agreement rating, and items formulated as goals, which require an importance rating. Both were rated on a 6-point Likert scale (Statements: 1 = strongly disagree to 6 = strongly agree; Goals: 1 = not important to me to 6 = extremely important to me). The internal consistencies are reported in Table 2.

Need to belong

Need to belong was assessed with the 10-item Need to Belong Scale (Leary et al., 2013Footnote 2). A sample item is “I want other people to accept me”. We used the German translation provided by Hartung and Renner (2014), ω = 0.75. Items were answered on a 5-point scale (1 = not at all, 2 = slightly, 3 = moderately, 4 = very, 5 = extremely).

Need to be alone

Need to be alone was assessed using the four-item appetence subscale of the desire for being alone from the ABC Scale of social desires (Hagemeyer et al., 2013), ω = 0.83. A sample item is “I like to be completely alone”. Items were answered on a 7-point frequency scale ranging from 1 = never to 7 = always.

Social anxiety

Social anxiety was measured using the SIAS-6 (Peters et al., 2012). Sample items include “I have difficulty talking with other people“. We used the corresponding German translations of the SIAS-6 items provided by Stangier et al. (1999), ω = .88. Items were answered on a 5-point Likert scale (1 = not at all, 5 = extremely).

Big Five traits

The BFI-2 consists of 60 items and measures the Big Five personality traits extraversion, negative emotionality, agreeableness, conscientiousness, and open-mindedness (Soto & John, 2017; German version: Danner et al., 2016). In addition, each trait consists of three facets, such as Sociability, Energy, and Assertiveness for the trait Extraversion, with four items each (all items are listed in Soto & John, 2017). Items were answered on a 5-point Likert-scale (1 = disagree strongly to 5 = agree strongly). The internal consistencies are reported in Table 2.

Social contact

Participants were asked “How often did you engage in social interactions during the last week?” for three different relationship categories (family, friends, colleagues) and four contact channels (personal contact, calls, video calls, texts). Answer categories included 1 = not at all, 2 = once, 3 = multiple days, 4 = daily, and 5 = multiple times a day. We analyzed personal contact with each relationship category separately, while the mean across all digital communication channels served as indicator for indirect contact for each relationship type.

Data exclusion and outlier detection

We used multiple criteria to screen the data for noncompliant responding behavior (see Meade & Craig, 2012), and excluded participants (a) who answered dozens of items on one page unrealistically quickly (i.e., less than 70 s for 39 items of the Social Dynamics Scale, less than 90 s for 60 items of the BFI-2), (b) failed the attention checkFootnote 3, and (c) demonstrated odd answering patterns as detected through the careless package in R (i.e., max. longstring, psychometric synonym metrics). Participant exclusion and attrition are shown in Fig. 2. Outliers (M ± 3 SD) concerned less than 1.5% of the sample. The analyses were conducted twice using the original or the winsorized variables, i.e., outliers recoded to M ± 3 SD. All results were identical after rounding.

Attrition analyses

To assess sample selectivity due to attrition over time, we compared participants who provided valid data in all four assessments (n = 165) with those who were invited to the longitudinal study but dropped out before completing all assessments (n = 55). Participants who remained in the study reported a stronger Social oversatiation (d = 0.39, p = .025), a weaker affiliation motive (d = -0.41, p = .009), weaker social anxiety (d = -0.34, p = .046), and were younger (on average 6 years, p = .007). There were no significant differences between groups with regard to gender, Family-friends interdependence, Social deprivation, Big Five personality characteristics, or fear of rejection (all |d| < 0.22; p ≥ .124), or need to be alone (d = 0.32, p = .061).

Results

We first describe results of the item selection procedure, retest reliability, and results from confirmatory factor analyses. The remaining sections of the result section address convergent, discriminant, and predictive validity of the Social Dynamics Scale.

Part 1: item selection

For reasons of parsimony, our goal was to reduce the initial item pool of 39 items to five or less items per subscale. Using the data from Study part 1 (i.e. first assessment wave), we excluded items that had very low interitem correlations within their respective subscales and either touched on peripheral aspects or mixed the construct in question with other topics (e.g., Social deprivation and Family-friends interdependence “I miss my family, if I am away from them for several days”). Based on discussions of the item content, we also discarded items where answering in a certain way could be considered rude (e.g., “Seeing my family only on holidays and birthdays would be sufficient for me”). We further discarded two highly skewed items and one very long item (see Table S1). The remaining 27 items all showed sufficiently good item characteristics (Table S1). Therefore, our final selection was guided by the following principles: (a) avoiding too much overlap in item content and wording, (b) choosing items with easy and intuitive wording, and (c) including items from a broad range of item difficulties. Based on these considerations, we slightly modified two items measuring Social deprivation.Footnote 4 We first selected five items for each subscale; however, this 15-item version later showed insufficient model fit in CFA. Excluding one of two very highly correlated items of the FFI subscale and one item with high cross-loadings on the Social deprivation subscale led to better model fit (see section Factorial Validity). We therefore chose four items per subscale for the final version and report results on CFA model fits and reliabilities for five-item and three-item versions in the supplementary materials (Tables S2 and S3). Summary statistics and psychometric properties of the final items of the Social Dynamics Scale are shown in Table 1.

Table 1 Wordings and psychometric properties of social dynamics scale items at T1 (n = 280) and T4 (n = 356)
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Part 1: factorial validity

Using the data from the first assessment wave, the correlation plot of the items (Fig. 3) showed that items belonging to the same subscale had substantial intercorrelations and, with a few exceptions, no substantial cross-correlations. Since we had strong theoretical reasoning regarding three distinguishable domains of social dynamics, we conducted a confirmatory factor analysis: Specifically, we specified three latent correlated factors and four items for each factor using the three-stage robust diagonally least squares estimator with the lavaan package in R. The model showed acceptable fit with Χ² (51) = 147.32, p < .001, CFI = 0.915, TLI = 0.890, and RMSEA = 0.088. Table 1 displays the factor loadings. As an alternative structure, we specified a two-factor solution with Social oversatiation and Social deprivation combined into one factor and Family-friends interdependence as a second factor, yet this model yielded an unacceptable fit: Χ² (53) = 326.72, p < .000, CFI = 0.764, TLI = 0.706, and RMSEA = 0.144.

Fig. 3
figure 3

Correlations between items of the social dynamics scale (T1, n = 280). Note Blue indicates positive correlations, and red indicates negative correlations

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Part 1: reliability: internal consistency and retest reliability

We estimated the reliability by calculating total ω and retest correlations of the SDS subscales. The subscales each showed very good internal consistencies at the first assessment wave: Family-friends interdependency ω = 0.81, Social oversatiation ω = 0.81, Social deprivation ω = 0.84. The internal consistencies could be replicated at T4 (n = 356 including the boost sample): Family-friends interdependency ω = 0.79, Social oversatiation ω = 0.82, Social deprivation ω = 0.85. The 3-week retest correlations were r = .87 for Family-friends interdependence, r = .79 for Social oversatiation and r = .83 for Social deprivation. The 6-week retest correlations were comparable with r = .84 for Family-friends interdependence, r = .85 for Social oversatiation and r = .84 for Social deprivation. Overall, all three subscales demonstrated very good reliability.

Part 1: convergent and divergent validity

We used the qgraph package (Epskamp et al., 2012) to visualize how the constructs of the Social Dynamics Scale were embedded within the larger nomological network of measures of social behavior and personality (see Fig. 4). Table 2 reports descriptive statistics and point estimates of the intercorrelations among all included variables for the first and last assessment waves. As can be seen in Fig. 4, Family-friends interdependence, Social oversatiation, and Social deprivation belonged to a part of the nomological network rather independent from the Big Five traits. Since the Social Dynamics Scale and most other assessed constructs focused on social phenomena, extraversion emerged as a relatively central node in the network. Most associations between the subscales of the Social Dynamics Scale and the other assessed constructs were consistent with our theoretical reasoning.

Table 2 Descriptive information and intercorrelations at T1 (lower diagonal, n = 280) and T4 (upper diagonal, n = 356)
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Associations between the subscales of the social dynamics scale

As expected, Family-friends interdependence was clearly separable from Social oversatiation (r = .17, p = .001) and Social deprivation y (r = − .11, p = .044). However, the directions of both associations were contrary to our hypotheses: The more people reported preferring friends to their family, the more they felt Social oversatiation and the less they felt Social deprivation generally. Furthermore, as predicted, the more people reported experiencing Social oversatiation, the less they reported experiencing Social deprivation (r = − .53, p < .001); however, this association was stronger than expected.

Fig. 4
figure 4

Nomological network of Social Dynamics Scale (T4, n = 356). Note This network graph is a graphical representation of the zero-order correlations between all variables measured at T4 (n = 356). Each node represents a construct, and each edge (line) represents a correlation between two constructs. Green/solid edges indicate positive correlations, red/dashed edges negative correlations, and the width of the edges corresponds to the relative strength of the correlations (i.e., thicker lines denote stronger associations)

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Family-friends interdependence

Family-friends interdependence could be clearly distinguished from all other assessed constructs (Fig. 4). The strongest correlations were with conscientiousness (r = − .24, p < .001), agreeableness (r = − .24, p < .001), and need to be alone (r = .16, p = .003). Unexpectedly, with increasing age, people did not report a stronger preference for friends or family (r = − .04).

Social oversatiation

Social oversatiation emerged as a relatively central node in the network (Fig. 4). With stronger the Social oversatiation, people’s need to be alone was stronger (as hypothesized, r = .52, p < .001), the weaker was their affiliation motive (r = − .71, p < .001), and the less they reported being extraverted (r = − .49, p < .001). Moreover, with stronger Social oversatiation, people had higher values in neuroticism (r = .38, p < .001), fear of rejection (r = .34, p < .001), and social anxiety (r = .33, p < .001), and lower values in agreeableness (r = − .30, p < .001). Social oversatiation was not significantly associated with age (r = .02).

Social deprivation

With stronger general Social deprivation, people reported stronger affiliation motives (r = .63, p < .001), need to belong (r = .42, p < .001), extraversion (r = .32, p < .001), and a weaker need to be alone (r = − .61, p < .001). In contrast to Social oversatiation and affiliation, Social deprivation was not associated with neuroticism, fear of rejection, or social anxiety (all p > .05). With increasing age, people reported experiencing less Social deprivation (r = − .17, p = .001).

All three subscales were empirically distinguishable from the Big Five measures, fear of rejection, social anxiety, and need to belong (Fig. 4). Regarding convergent validity, the subscales of the Social Dynamics Scale were associated with affiliation motive and need to be alone in the hypothesized directions. The associations of Social oversatiation and Social deprivation with affiliation motive and need to be alone were stronger than expected. Yet, as shown in Table 2, Social oversatiation showed correlational patterns distinct from those of Social deprivation and need to be alone, and Social deprivation showed correlational patterns distinct from affiliation motive. Social oversatiation and affiliation motive, as well as Social deprivation and need to be alone showed consistent correlational patterns with measures of social behavior and personality but showed somewhat different associations with age. In sum, the results support the construct validity of Family-friends interdependence and provide partial evidence for convergent and divergent validity of the Social oversatiation and Social deprivation-subscales.

Part 2 predictive validity: predicting change in personal and indirect social contact

Analytic approach

To examine the predictive validity of the Social Dynamics Scale, changes in personal and indirect contact with friends or family across time when contact restrictions were loosened were analyzedFootnote 5, as well as how the changes varied with general tendencies of Family-friends interdependence, Social oversatiation, and Social deprivation. Because the data formed a multilevel data structure with measurement occasions (i.e., T1 to T4) nested within people, the data were analyzed with multilevel models (MLM) using Mplus (Version 8.3). Compared to a repeated-measures ANOVA, these models have the advantage of taking missing data into account and retaining participants with missing data. In all models, social contact with friends or family was the outcome, while time, one of the three subscales of the Social Dynamics Scale (SDS) measured at T1, and the interaction of time and the respective SDS subscale were predictors. The time variable was zero-centered, with the starting time of the study in the beginning of April, 2020 as zero when contact restrictions were strictest, and scaled in months. All models were set up as conditional growth models, in which the trajectory of contact across time (i.e., slope of time) was allowed to vary between people, and this variation was predicted by the Social Dynamics Scale. Values of the Social Dynamics Scale were grand mean-centered at level 2 (i.e., participants) prior to estimating the models. We used separate models to predict personal, as well as indirect contact each separately for family and friends. Thus, 12 models (3 social dynamics subscales by 2 contact modes by 2 relationship types) were estimated using the full information maximum likelihood estimator. The parameter estimates for the fixed effects of all models are reported in Table 3, and interaction plots for personal contact are displayed in Fig. 5.

Table 3 Model parameters for changes in personal and indirect contact frequency by relationship type
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Individual differences in social dynamics predict change in personal and indirect social contact

Personal contact with both friends and family significantly increased across time, when contact restrictions were gradually loosened (Table 3; Fig. 5). Individual differences in Family-friends interdependence did not moderate changes in personal contact with friends or family (Table 3, upper part). People with a stronger tendency to experience Social oversatiation reported a weaker increase in their personal contact with friends, b = -0.05, p = .020 (Fig. 5C). As predicted, the stronger people rated their general Social deprivation, the stronger their personal contact with friends increased over the study period during early summer 2020, b = 0.05, p = .005 (Fig. 5E). Changes in personal contacts with family were not predicted by Social deprivation nor Social oversatiation (Table 3, second column).

Notably, with a stronger general preference for friends, people reported more personal contact with friends, yet less contact with family at T1, despite being advised to only have contact with immediate household members (Table 3, main effects of FFI in columns 1 and 2, Fig. 5A and B). In contrast, individual differences in experiencing Social deprivation or Social oversatiation were not significantly associated with the amount of personal contact with friends and family at T1, that is, at the time of strictest social distancing regulations (Table 3, main effects of Social deprivation and Social oversatiation).

Results for indirect contact partly complemented the results of personal contact such that across time indirect contact with friends and family decreased. People who preferred friends over family also reported less indirect contact with family, b = -0.17, p < .001 (Table 3, last column, upper part). People with a stronger tendency to experience Social oversatiation reported even less indirect contact with friends at T1, b = -0.19, p < .001. Furthermore, people who experienced Social deprivation more strongly, reported more indirect contact with friends and family at T1, that is, at the time of strictest social distancing regulations (friends: b = 0.14, p < .001; family: b = 0.13, p = .002).

Fig. 5
figure 5

Fixed effects of multilevel models for personal contact with friends and family (A-F). FFI subscale and contact with friends (A) as well as with family (B); SoS subscale and contact with friends (C) as well as with family (D); SOD subscale and contact with friends (E) as well as with family (F). Note Personal contact with friends and family is displayed as a function of time, the three subscales of the Social Dynamics Scale (SDS), and the interaction of time and SDS. For illustrative purposes only, the predicted values for the mean plus and minus one standard deviation on the SDS subscales are displayed, while SDS subscales were always modelled as continuous predictor. The main effect of time was significant in all models (all p < .05). Effects of time, all other main effects, and interaction effects are reported in Table 3. FFI = Family-Friends Interdependence, SOS = Social oversatiation, SOD = Social Deprivation. Effects for indirect contact, which decreased across time, are not displayed because results mirror effects of personal contact

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Discussion

The current study addressed individual differences in social dynamics: interdependencies among different social relationships as well as within relationships across time. Specifically, we described a direct approach to measure individual differences in Family-friends interdependence, Social oversatiation, and Social deprivationFootnote 6. To substantiate the theoretical considerations that the three concepts are related, yet distinct aspects of how people maintain social relationships, we reported and now discuss results on internal consistency, factorial structure, temporal stability, as well as convergent, divergent, and predictive validity.

Although social dynamics are inherently short-term social behaviors that manifest in daily life (Back et al., 2011, 2023), we argue that self-concepts of social dynamics can be validly assessed based on self-reports—similar to other self-concept domains, such as Big Five traits (e.g., Soto & John, 2017), attachment (Fraley & Roberts, 2005), the need to be alone (Hagemeyer et al., 2013), or social anxiety (Peters et al., 2012). Similar to how other self-concepts are formed (Quintus et al., 2021; Wrzus, 2021), people likely observe their affective and behavioral reactions after (subjectively) insufficient or excessive social contact with family, friends, and others, and memorize these observations as self-concepts. Also similar to other self-concept domains, these relatively time-stable representations are assumed to be motivated and subjective memories instead of objective, fully accurate accounts (Vazire, 2010; Wrzus, 2021). As we discuss later, such generalized self-concepts still hold value for understanding individual differences in the dynamics of social relationships.

Scale development: internal consistency, factorial structure, and temporal stability

Based on the theoretical considerations on Family-friends interdependence, Social oversatiation, and Social deprivation, we developed 39 initial items, which were examined in an age- and education-diverse sample. During the item selection process, we selected items with desirable item properties (i.e., skew, kurtosis, item difficulty, interitem correlation; Bühner, 2011). We simultaneously considered semantic aspects (e.g., brief wording, different aspects of covered content) and chose this approach over machine learning algorithms (e.g., ant colonization, genetic algorithms; Olaru et al., 2018) because machine learning usually neglected content aspects. Instead, machine learning optimizes item selection based on item or scale properties, such as distribution parameters or item difficulty (Olaru et al., 2018).

To develop an economic scale, we aimed at five or less items per subscale, that is, 15 or less items in total. With at least 4 items per subscale, the subscales demonstrated high internal consistencies of 0.80 and higher as well as a high 3-week and 6-week retest stability of around 0.80. The three subscales of social dynamics are thus comparable to other self-report instruments for assessing personality characteristics regarding both internal consistency and temporal stability over several weeks (Hagemeyer et al., 2013; Soto & John, 2017). The 15-item version showed insufficient model fit due to two items on the Family-friends interdependence subscale that were too highly correlated, and one item with high cross-loadings between the Social deprivation and Social oversatiation subscales. Thus, a 12-item version of the Social Dynamics Scale is preferred for psychometric reasons. Still, some controversy exists on the strictness when evaluating measurement models of personality scales (i.e., structural validity; Sellbom & Tellegen, 2019). Common criteria for model fit in confirmatory factor analysis seem to be rather strict for personality scales, and several established personality scales (e.g., NEO PI-R, MPQ, HEXACO, 16PF, CPI) often fall short of common model fit criteria (Hopwood & Donnelan, 2010). One viable approach in addition to model fit indices is considering further forms of validity, such as convergent and predictive validity (Hopwood & Donnelan, 2010; Sellbom & Tellegen, 2019).

Divergent, convergent, and predictive validity

As expected, all three social dynamics subscales (i.e., Family-friends interdependence, Social oversatiation, and Social deprivation) emerged as rather independent from Big Five traits in the nomological network—with the exception that the more people rated themselves as extraverted, the less they reported a disposition towards experiencing Social oversatiation. This association between extraversion and (lower) general Social oversatiation might result from the Sociability and Energy facets of extraversion: People, who frequently engage in social interactions (i.e., higher Sociability) partly do so because they experience social interactions as pleasant and rewarding and less as straining (Jacques-Hamilton et al., 2019; Soto & John, 2017), and thus they experience less Social oversatiation. Our data support this interpretation because general Social oversatiation was indeed lower with higher Sociability and higher Energy level, while the facet Assertiveness was loosely associated with Social oversatiation (supplementary Table S5).

The newly developed subscales Social oversatiation and Social deprivation showed convincing convergent validity based on strong associations with other interpersonal dispositions (i.e., affiliation motive, need to belong, need to be alone). This was expected based on the theoretical linkage between affiliation motive and consequences of motive dissatisfaction: The more people need and seek social contact, the more it is possible that the need is not (fully) satisfied, which is experienced as Social deprivation. Conversely, the less people need and seek social contact, the more it is possible that (unwanted) social contact exceeds a person’s need, which is experienced as Social oversatiation. The complementary nature of Social oversatiation and Social deprivation was also apparent in their bivariate association, that is, with a stronger individual tendency to experience Social oversatiation, the tendency to experience Social deprivation was less pronounced. Still, we kept the two subscales as separate factors because the two subscales describe very distinct processes in daily social interactions, that is, social contact exceeding versus falling below desired social contact. Compared to assessing social contact and whether it exceeds or falls below the social needs with momentary assessments (e.g., experience sampling methods, mobile sensing; Müller et al., 2019; Sun et al., 2019), Social oversatiation and Social deprivation might be difficult to separate in general retrospective reports. This becomes apparent through the negative correlation between the two general tendencies. Nonetheless, the self-ratings of the general tendencies can be valuable for panel studies or samples where behavioral observation is not possible (e.g., some clinical settings).

The complementary nature of individual differences in experiencing Social oversatiation and Social deprivation also became visible when examining predictive validity. After a period of strict, nationwide social contact restrictions in 2020, people, who generally experience Social deprivation more strongly, increased more strongly in self-reported personal contact with friends, whereas people, who experience Social oversatiation more strongly, increased contact at a lower rate. Thus, whereas previous research demonstrated short-term effects of Social deprivation or oversatiation (i.e., during laboratory experiments, Maner et al., 2007), the current findings demonstrate that similar effects occur over a period of several months—likely because social contact restrictions were much more severe than in laboratory studies and only gradually loosened.

Family-friends interdependence, the preference to be with family, with friends, or similarly with both, was clearly distinct from Big Five traits and further interpersonal dispositions, such as affiliation motive, need to belong, need to be alone, fear of rejection, or social anxiety. Thus, divergent validity was established. Previous research postulated that the affiliation motive can be satisfied in diverse social relationships (e.g., Hofer & Hagemeyer, 2018). Thus, a stronger preference for family or friends can exist independently from the strength of the affiliation motive (or related constructs)—which is exactly what was observed in the current study. Similarly, social anxiety and fear of rejection mainly manifest in interactions with unknown or scarcely familiar people (Asendorpf, 1990; Russel et al., 2011). Since close friends can be as familiar as family (Mund & Neyer, 2014; Wrzus et al., 2012), a preference for one or the other is also largely independent from social anxiety, which is supported in the current results. Although the number of and contact frequency with friends is often higher for people higher in extraversion and agreeableness (e.g., Wagner et al., 2014; Wrzus et al., 2016), a relative preference for friends of family seems to be rather independent from these two and the other Big Five traits (Buijs et al., 2023). Perhaps, Family-friends interdependence as a preference for one over the other depends more strongly on the specific available friends and family or the quality of the relationships (e.g., Wrzus et al., 2012).

Despite few empirical associations with other (interpersonal) dispositions, Family-friends interdependence seemed to be measured validly, as the associations with the amount of personal and indirect contact demonstrated: With a stronger preference for friends (over family), people reported more contact with friends, yet less contact with family during the contact restrictions.

In summary, the Social Dynamics Scale reliably assessed relatively stable individual tendencies towards family or friends, Social oversatiation, and Social deprivation as well as demonstrated convincing divergent, convergent, and predictive validity. The partly very high correlations among Social oversatiation, Social deprivation, affiliation motive, need to belong, and need to be alone might be attributable to common method variance as associations were smaller and still substantial, when assessing social dynamics with momentary assessments in people’s daily lives (e.g., Reference blinded for review; Zygar et al., 2018).

Limitations and future directions

The current study proposes Family-friends interdependence, Social oversatiation, and Social deprivation as interpersonal dispositions, which capture dynamic interdependencies among social relationships—both across relationship types and time. In addition, the study aimed to develop and validate a brief measure to assess individual differences in these interpersonal dispositions reliably and validly. We embedded the study and the scale development in the strong theoretical background of affiliation motive theory and used a heterogeneous sample as well as strong methodological and statistical approaches to meet the study aims. Still, some limitations and directions for future research need to be addressed.

First, as discussed before, the study measured self-concepts of social dynamics. Though this approach is routine for many personality dispositions that intend to capture relatively stable differences in people’s thoughts, feelings and behaviors, future studies should aim to directly observe social dynamics in daily life. Mobile sensing might be extended to not only assess whether social contact occurred (e.g., Roos et al., 2023; Sun et al., 2019) but also with which person or what kind of relationship (e.g., romantic partner, friend). At the same time, behavioral observation, which is per se blind to internal thoughts and feeling, might detect fewer traces of Family-friends interdependence or Social deprivation, when external constraints override preferences and needs. For example, a person might prefer to spend time with a specific friend, but they might not be able to meet the friend because of family obligations or because the friend is unavailable (e.g., Buijs et al., 2023). Similarly, a person might experience Social oversatiation and the desire for no further personal contact but might not be able to avoid contact because of obligatory appointments or other external demands (e.g., Coplan et al., 2019; Krämer et al., 2023).

Second, data collection ended in June 2020 due to restricted resources, but social-distancing rules were further loosened afterwards and tightened again in the fall. It is possible that (a) under conditions of unrestricted social contact, the subscales of the Social Dynamics Scale would show somewhat different intercorrelations, and (b) the effects of Social Dynamics Scale to predict change in social contact might have been even stronger if examined over a longer time period. One argument against such temporal effects is that scale intercorrelations were rather similar across the two study periods at the beginning of April and in the middle of June, when different contact restrictions existed. In addition, other studies that examined differences in people’s well-being covered a similar time period (e.g., Zacher & Rudolph, 2021), yet focused on loneliness or subjective well-being without taking different forms of social contact into account.

Finally, we developed and tested the Social Dynamics Scale in a sample of German adults and future studies could examine the levels of Family-friends interdependence, Social oversatiation, and Social deprivation in other cultures, countries, and age groups (i.e., children, adolescents). We assume that the overall level of Family-friends interdependence or Social oversatiation could differ in these other populations. For example, social network compositions differ between cultures, though not always between ethnicities within a country (Fung et al., 2001, 2008), which could indicate cultural differences in Family-friends interdependence. Similarly, since social networks and the density of living conditions also contribute to how much oversatiation and deprivation people experience (Reference blinded for review), cultures with differences in social networks and living conditions could also differ in the average level of Social oversatiation or deprivation people experience. With respect to age, we assume that children will show a higher preference for family over friends on average due to parents and siblings being the central relationships in children’s social lives (Berk, 2015; Bowlby, 1969/1991). When adolescents increasingly detach from parents and focus on peer relationships (Hartup & Stevens, 1997; Reitz et al., 2014), individual differences in the Family-friends interdependence will develop depending on how extensively adolescents focus on peer relationships. At the same time, in every culture or age group people likely differ from each other in the three studied aspects of social dynamics. These individual differences in social dynamics result from environmental characteristics as well as the general human need to maintain social relationships, which exists in all people although to a different extent (for review see Hofer & Hagemeyer, 2018).

Conclusion

People have the need to form and maintain fulfilling social contacts, yet they differ with respect to with whom they satisfy the need and how quickly this need is deprived or overly satiated. Accordingly, the current longitudinal study focused on theoretically delineating such social dynamics as well as on measuring individual differences in (a) Family-friends interdependence, (b) Social oversatiation, and (c) Social deprivation as three aspects of social dynamics. For situations and samples where direct behavioral observation is not feasible or misleading (e.g., strong external constraints, too brief observation periods to detect individual differences reliably), the newly developed brief self-report questionnaire, the Social Dynamics Scale (SDS), could provide a useful complementary approach. The current results demonstrate that individual differences in the tendencies to experience Family-friends interdependence, Social deprivation, or Social oversatiation can be measured reliably, validly, and with predictive value for changes in daily contact with family and friends.