This article represents an effort to reveal to the monolingual English-speaking behavior analytic community what is being done in other languages and traditions. In particular, we outline and examine the implications of a field orientation to study interindividual relations, called sociopsychology (Ribes-Iñesta et al., 2016). Our aim is to provide a review of sociopsychology as a scientific system.

From an interbehavioral standpoint, a scientific system is built on the articulation of five classes of definition (Kantor, 1958, pp. 77–83), namely, (1) defining the subject matter as a distinctive event; (2) defining the possible levels of description of the event; (3) defining the factors or components and types of events; (4) defining the basic operations, methods, instruments, and experimental designs, and (5) defining the sort of premises arising as products of scientific work. Considering these five types of definitions, we will examine sociopsychology as a scientific system.

Definitions (1): Sociopsychology as a Distinct Multidisciplinary Enterprise

Ribes-Iñesta (2005, 2018) proposes an analysis of the terms “discipline,” “multidiscipline,” “interdiscipline,” and “transdiscipline” as they relate to different types of scientific knowledge. From this vantagepoint, we will later justify why sociopsychology is defined as a multidiscipline. Let us first examine the meaning of the four disciplinary relations as types of knowledge. Scientific disciplines are built based on the identification of a segment of the world, constructing a certain type of knowledge that encapsules abstract properties, measurements, types of data, and interpretations (Ribes-Iñesta, 2003). Multidisciplines, in turn, consist of the intersection between two or more disciplines in terms of a predominant theoretical logic and a preferred methodology. The identified multidisciplinary field always constitutes a specific level of analysis that can’t be reduced to either of its constituent disciplines. Multidisciplines are established as an intersecting field of knowledge between two disciplines, using empirical data tangential to each discipline.

Interdisciplines are formulated based on already identified social issues rather than from the identification of a unique subject matter. For example, medicine was historically established due to the explicit need to cure illnesses. Its existence has been justified throughout the years on the basis of a continuous need to solve various health issues. In this sense, medical practices employ different kinds of knowledge such as biology, psychology, physics, and chemistry (Ribes-Iñesta, 2018). In general, interdisciplines tackle a wide range of day-to-day problems by merging scientific knowledge, technologies, and other types of knowledge. Examples of interdisciplines include administration focused on finances, engineering and architecture focused on household needs, and pedagogy focused on education.

Interdisciplines produce professionals and services that tailor scientific knowledge to the needs of specific populations. In contrast, disciplines and multidisciplines produce research, involving the formulation of questions directed toward answering problems of the relevant theory. Researchers are trained to innovate existing knowledge into new knowledge, and this activity constitutes its own end in science. The use of scientific knowledge towards finding ways to fix or solve a social problem can only be achieved through interdisciplinary work. In this sense, applications of scientific knowledge must meet specific social criteria rather than simply answer theoretical questions. As Feyerabend (1975) put it, “the objection that citizens do not have the expertise to judge scientific matters overlooks that important problems often lie across the boundaries of various sciences so that scientists within these sciences don't have the needed expertise either” (p. 251).

Lastly, transdisciplines consist of scientific products employed for different disciplinary aims and interests. For example, mathematics is a transdiscipline insofar as different metric systems are adapted to different disciplines and specific subject matters (e.g., atomic weights, light years).

Sociopsychology is a multidisciplinary extension of an interbehaviorist theory of behavior (Ribes-Iñesta & López-Valadez, 1985). Sociopsychology is an intersection of knowledge between psychology and the sociohistorical science. The latter defines the phenomena that can be analyzed––phenomena related to social formations. The former provides the method to study the empirical phenomenon: the interindividual relations as components of institutional practices. This can be done from three analytic levels (exchange, power, and sanction contingencies).

Two additional precisions can be provided concerning the disciplinary relations constituting sociopsychology (see Figure 1 for a representation of these relations). First, the method of sociopsychology is based on the study of human behavior from the perspective of behaviorist field theory (Ribes-Iñesta & López-Valadez, 1985). Second, the empirical world of sociopsychology is interindividual relations as molecular segment of social or institutional practices. A social formation in itself is the subject matter of anthropology, sociology, economics, jurisprudence, history, and political science, collectively seen as a single discipline called sociohistorical science (Ribes-Iñesta et al., 2016). Sociopsychology studies relations among individuals as interindividual relations that take their forms from the organization of the social formation in which they develop. The interindividual relation consists of three types of contingencies: exchange, power, and sanction.

Fig. 1
figure 1

Representation of Relations between Sociopsychology and Other Modes of Knowledge. Note. D = Discipline, M = Multidiscipline, I= Interdiscipline, T = Transdiscipline. Adapted from Ribes-Iñesta (2005)

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Definitions (2): Levels of Description of Interindividual Relations

“All interindividual relations constitute a molecular segment of an institutional practice” (Ribes-Iñesta et al., 2016, p. 8). Sociopsychology is not the study of social formations per se—as previously stated, this phenomenon only corresponds to social science. It studies the molecular segments of social practices seen as the behavior between individuals (i.e., interindividual relations). The social formation as a whole is conceptualized as interlaced institutional practices (detailed below). Thus, interindividual relations represent segments of different types of institutional practices, which can be experimentally observed and manipulated. Interindividual relations have three dimensions or levels of description: exchange, power, and sanction relations. A sociopsychological analysis of an interindividual relation entails the identification of the three dimensions of behavior between individuals (exchange, power, and sanction), and the sociohistorical circumstances under which those relations occur. In this section, we outline the definition of institutional practices and the two different types of these practices.

Institutional Practices

From an interbehavioral (Kantor, 1982) standpoint, institutions refer to stimulus functions of objects (psychological phenomena) as well as collective practices (sociological phenomena). From a sociopsychological level of analysis, “the relations [that humans] establish with their surroundings and other individuals differ from those relations established among other animals insofar as human relations are part of practices recognized in the form of institutions” (Ribes-Iñesta et al., 2016, p. 173, emphasis added). Institutional practices do not influence the behavior between individuals, rather they constitute two logical levels of analysis of exchange, power and sanction dimensions, namely, formal and informal institutions. These two types of institutional practices constitute the “architecture” or structure of a social formation. Informal institutions represent the organization of the collective practices considered “the culture.” Formal institutions represent the organization of the collective practices considered “the State.” Thus, interindividual relations occur under interlaced practices of culture and State. Formal and informal institutions operate with relative independence from each other, so that changes in one direction for one may not mean changes in the same direction for the other.

Formal Institutional Practices

The behavior between individuals can be defined according to impersonal roles individuals adopt as part of their everyday life. Said another way, human interactions can occur as part of formal collective practices when individuals behave as if they were impersonal actors, so that the roles––not the individual histories––define the relation. In this sense, civil responsibilities and rights, educational status or degrees, religious membership, accumulated commodities and wealth, and legality, among others State-related activities, are the formal institutional practices in a social formation. The set of possible formal institutions in a social formation constitute the “communal life” of an individual (Ribes-Iñesta, 2018).

Informal Institutional Practices

The behavior among individuals can also be defined according to interpersonal roles individuals adopt as part of their everyday life. Said another way, human interactions can occur as part of informal collective practices when individuals interact with others in terms of their particular, shared histories. The so-called cultural practices, such as food, music, family, rivalry, friendship, love, lies, deceit, treason, and trust are the informal institutional practices in a social formation. The set of possible informal institutions in a social formation constitute the “cultural life” of an individual (Ribes-Iñesta, 2018).

Of course, individuals have both a cultural and a communal life, participating in various institutional practices. Sometimes these practices may influence one another, so that an individual behaving under interpersonal roles may also adopt impersonal ones, or vice versa. On one side, formal criteria may regulate interpersonal relations, such as when divorced parents (interpersonal roles) dispute over the legal custody (impersonal roles) of their children. On the other side, informal criteria may affect impersonal relations, such as when traffic police (impersonal roles) in Latin American countries stop cars in search of bribes (interpersonal roles).

Definitions (3): Descriptions of Specific Interindividual Relations

Interindividual relations are relations between individuals. This expression is meant to clarify that the three dimensions of interindividual relations, namely, exchange, power, and sanction, are relational properties rather than individual ones. Exchange, power, and sanction don’t happen to the individual, but rather individual happenings are always a part of these relations. According to Ribes-Iñesta et al. (2016), social formations emerge as the progressive organization of these relations, one built upon another, mutually influencing their structures and “outcomes.” Exchange relations are conceived as the deferred exchange of the products of labor between individuals. Power relations are conceptualized as the organization of exchange relations through domination of one over the other. Sanction relations represent the delimitation of obligations, rights, and values of individuals and their actions in power relations. It should be noted that interindividual relations are segmented into exchange, power, and sanction only for analytical purposes, and they are assumed to occur simultaneously rather than sequentially. Exchange, as division of labor, is the foundation of any interindividual relation. Power and sanction are transversal in a social formation, affecting the organization of exchange relations. The organization of interindividual relations and their interrelation with institutions is represented in Figure 2.

Fig. 2
figure 2

Generic Representation of Levels of Analysis of Interindividual Relations. Note. The dotted lines represent formal and informal institutional practices as synchronic cuts of a social formation. The solid lines represent two dimensions (power and sanction) of interindividual interactions as diachronic cuts of a social formation. Solid arrows are practices and “outcomes” of power and sanction contingencies (Ks)

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Exchange Relations

From a sociopsychological view, the division of labor is the fundamental human activity structuring exchange relations in every social formation (Ribes-Iñesta et al., 2016). These interactions are always deferred, that is, production (of goods or services) occurring here and now is appropriated by other individuals then and later. Deferred relations between individuals can only occur through language, which is the medium of contact for all human social behavior (see Definitions 5). Exchange relations are inherent to human groups insofar as language is conventional and are not related to animal cooperative behavior. “Services, as well as goods, can be conceived as products of labor insofar as they constitute an effect, and this effect is always a product directed towards to another individual or individuals in a specific institutional context” (Ribes-Iñesta et al., 2016, p. 223). In this sense, the production-appropriation relation is the main component of exchange relations. The “outcomes” of the deferred exchange of products of labor is complementation of the behavior between individuals. Complementation is not the same as mutual aid; rather, it focuses on collaboration whereby each individual contributes something different from the others. Complementation between individuals, based on goods and services, is always asymmetrical and can be studied in various interindividual relations, such as cooperation, competition, altruism, equity, and the like. These are all forms of complementation, that is, they result from the specialized division of labor in exchange relations.

Power Relations

Power has been traditionally conceived as a transversal phenomenon in all social practices (Foucault, 1982), and the effects of power in social structure continue to be a major research interest among contemporary researchers in the social sciences (cf. Molm, 2001). However, from a sociopsychological perspective, power is described as hierarchical access and manipulation of labor. Power is one of three dimensions of interindividual relations, and always studied with respect to exchange and sanction relations. In particular, Rangel-Bernal (2008) emphasizes the interdependencies between power and authority as factors structuring interindividual relations. Power is not something one does or says, but rather it is a relational feature of interindividual interactions. Power not only pertains to the behavior of individuals, but also to their possibilities of action in terms of available resources and knowledge. The “outcome” of power is domination over others in the behavior between individuals (Ribes-Iñesta et al., 2016). Domination can be studied as practices of prescribing, supervising, and administering consequences in exchange relations.

Sanction Relations

According to Ribes-Iñesta et al. (2016), sanction is the most complex dimension of the interindividual relation, insofar as it is exclusively observed in human social interactions, that is, there are no analogous interactions in other social animals. From this view, sanction is not limited to applying rewards or punishments to an individual, but the term also encompasses delimitation, access, isolation, recognition, and exclusion. Although sanctions may be stated formally as norms and rules (i.e., formal institutional practices), they also occur as advice, corrections, and deliberation among others (i.e., informal institutional practices). Unlike exchange and power relations (of which analogous interactions may be found in nonhuman social groupings), sanctions are exclusively conventional practices. Sanctions always pertain to religious, legal, ethical, and moral practices. The application of sanction, as recognizing and penalizing activities, determines the relevance, effort, consequences, and opportunities of participation of individuals in social affairs (Ribes-Iñesta et al., 2016). The “outcome” of sanctions relations is delimitation of the behavior between individuals. Delimitation can be studied as the legitimacy of actions of individuals (i.e., what is just and fair) participating in exchange and power contingencies (Ribes-Iñesta et al., 2016).

Definitions (4): Definitions of Method & Research Aims

Sociopsychology is primarily an experimental endeavor, offering data-based theoretical analysis of interindividual relations. Several studies have systematically investigated the three dimensions of interindividual relations, and three interrelated research lines have been developed: (1) Exchange relations studies, mostly about production-appropriation practices; (2) Power relations studies, concerning authority and obedience; and (3) Sanction relations studies, focused on transgression of norms, impunity, and delimitation of power. We now turn to these three research lines, first outlining their common method and logic to investigate interindividual relations, and later describing the particular research interests of each research line, their specific experimental manipulations and some findings.

The Puzzle Task

Ribes-Iñesta (2001) proposed the main experimental arrangement consisting of a puzzle task, and Ribes-Iñesta et al. (2008) provided taxonomies of interindividual relations. These two works are traditionally employed as guidelines to plan the methodology in sociopsychological studies. The traditional puzzle task (Ribes-Iñesta, 2001) involves two computers networked to one another and the use of two puzzles, each with their corresponding pieces. Some studies also involve a third element, a shared container of puzzle pieces. In general, the puzzle task sets up two main contingencies, whereby the participant may place puzzle pieces on their own puzzle (individual contingency) or their partners’ (shared contingency). This arrangement is proposed under the assumption that social contingencies alone are insufficient to produce social interactions, so that more manipulations are required to study exchange, power, and sanction relations. For this reason, the individual may interact with any puzzle at any given time of the experimental session, and the parameters of this interaction are always specified in each research line according to their experimental aims, as will be described below (e.g., confederates, agreements, instructions, symmetrical/asymmetrical distribution of puzzle pieces, among others).

The puzzles fill up the upper portion of the individual’s computer screen and the puzzle pieces are shown in the bottom half of the screen. In addition, the participant can interact with all the puzzles shown in their screen, wherein the left side shows Individual A’s puzzle, whereas their pattern is shown on the right side. The correct placement of puzzle pieces results in a determined number of points, in which earned points are tracked at the bottom of the screen, and time spent is shown at the top of the screen. Once the participant completes their own puzzle, they may choose to end the session, help their partner complete theirs, or don’t help them but don’t end the session either. These studies are sometimes conducted in a span of several days. In general, data are collected on dyadic performance, preferred measurements are number of correct piece placement on each puzzle (i.e., own vs. partner’s), number of pieces placed on each puzzle, types of verbal interactions (different categories according to the task), obtained points (individual and dyadic), and time to use all pieces. Data are commonly represented as cumulative records and time-series plots.

The puzzle task differs from an experimental analysis of social behavior (e.g., Lindsley, 1966; Marwell & Schmitt, 1975) in several ways. In social studies using operant procedures, cooperation, competition, and altruism are studied in terms of frequency of responding and the use of points and earnings as reinforcers for these responses. These studies show that cooperation and altruism can increase through reinforcement. In contrast, the puzzle task involves a choice procedure, whereby individuals can engage in individual contingencies or social episodes. Moreover, the criteria to determine the participation in a social episode is not restricted to shared responses and shared consequences. In the puzzle procedure, individuals tend to choose individual contingencies more often than working with their partner even though reinforcers are provided contingent upon choosing to participate in social episodes (Ribes-Iñesta & Rangel-Bernal, 2002; Ribes-Iñesta et al., 2003).

This basic experimental arrangement has been employed with multiple added manipulations, and in both experimental and natural settings. The puzzles vary in terms of materials and difficulty to solve, and these parameters are used across different populations (children, adults). Researchers commonly work with young population for these studies. Young individuals are expected to have less complex histories of social interactions, which should facilitate observing the differential effects of exchange, power, and sanction contingencies on their performance. One may consider, for example, the fact that power relations are inherent in the daily life of adults, or the fact that children do not necessarily participate in the economic retribution of labor.

Exchange Relations Studies

Following Ribes-Iñesta (2001), exchange contingencies consist in the production, distribution, and appropriation of goods and services. The factors that are parametrically manipulated in this line of studies are resource availability, tools, skills, expertise, and profits. Exchange relations are assumed to intersect with prosocial relations, so that effects are expected to occur in both directions. Prosocial behavior is not studied as cooperation, but as partial or complete altruism. According to Ribes-Iñesta (2001), the term “cooperation” is not appropriate to distinguish a specific type of prosocial relation because all social activities involve working together (even competition) and thus they could all be labeled as cooperative. In other words, “cooperation” is considered to be too generic for a technical term. Instead, the terms partial and complete altruism are preferred as technical descriptions of two sorts of prosocial activities, namely giving and receiving (partial altruism) and giving but not receiving (complete altruism). The introduction of these terms allows a further precision concerning the difference between altruism and competition, where only in the latter the individual takes without giving.

As such, exchange relations studies focus on the factors that increase or decrease engaging in partial versus complete altruism under shared contingencies, as well as the effects of production–appropriation relations on the frequency of participating in episodes of altruism (partial or complete). Exchange studies have primarily explored the role of reciprocal responding (i.e., correspondence of actions of the individual puzzle-piece placement with respect to the confederate’s actions) to promote partial altruism. Some of these studies have provided measurements of verbal interactions in terms of frequency and quality and their effects on choosing to work under shared contingencies (Ribes-Iñesta et al., 2008; Pulido-Avalos et al., 2014). Ribes-Iñesta et al. (2008) and Pulido-Avalos et al. (2014) found that participants who established strategic verbal interactions (i.e., agreements on how to complete the task) generally chose to work under shared contingencies of partial altruism despite the fact that maximum pay offs were obtained under individual contingencies.

Pulido-Avalos et al. (2015a, b) examined the effects of induction of reciprocity by a confederate on the choice of shared contingencies of total altruism and competition, respectively. The findings of these studies provided evidence concerning the pivotal role of the “other” to induce reciprocal responding. Reciprocal responding has been observed in free-operant procedures, wherein an individual can place a puzzle piece in the other’s or theirs without time restrictions (Ribes-Iñesta et al., 2010). It has also been found to occur under shared contingencies using turn-by-turn procedures, wherein an individual can only place a puzzle piece after the other individual places theirs (Rangel-Bernal et al., 2015). These findings collectively suggest that reciprocity is primarily a behavior-induced phenomenon independently of the type of procedures involved in the experimental task.

Pulido-Avalos et al. (2018) found that even when higher earnings were placed contingent upon choosing to work under individual contingencies, participants matched the confederate’s behavior under shared contingencies. In an exploratory study, Avila-Hernández and Pulido-Avalos (2018) studied reciprocity without establishing a feedback system (e.g., schedules of reinforcement), and found that by establishing a consistent history of interaction it was possible to obtain reciprocal responding. These findings suggest that partial altruism can be obtained independently of whether individuals can or can’t maximize their individual rewards.Footnote 1

Power Relations Studies

Following Ribes-Iñesta (2001), power contingencies are studied according to the effects of four types of behaviors of one individual over the others: prescription, regulation, supervision and administration of consequences. Prescription has to do with describing to participants the activities that must or can be done and their corresponding consequences. Regulation is established by intervening throughout the task, so that the prescribed requirements are maintained. Supervision refers to surveillance on adherence to the prescribed requirements as well as pointing out when they are not met. Administration has to do with delivering consequences. The basic puzzle task in these studies includes the addition of forbidden and assigned puzzle-pieces containers in order to study obedient and disobedient behaviors.

Rangel-Bernal and colleagues (Rangel-Bernal, 2008; Rangel-Bernal & Ribes-Iñesta, 2009; Rangel-Bernal et al., 2011) have explored the types of authority resulting from the different power relations (prescription, regulation, supervision, and consequences administration). Rangel-Bernal (2008) offers a key empirical distinction between obedience and compliance: the former is observed as the effect of a demand to complete a task under threat of sanction, whereas the latter is observed as the effect of a request to complete a task without threat. Thus, the difference made between obeying and complying is on the basis of factors corresponding to the “other” in the social interaction, rather than the behavior of the one performing the task. Further, obedience is obtained through authority figures, whereas compliance is obtained through social facilitation. The difference between obedience and compliance can be studied by manipulating the absence/presence of authority figures, as well as the types of authority (oral, written). In power relations studies, prescribing permitted/restricted behaviors (including the consequences) has been sufficient for school children to show low levels of disobedience. Two important conclusions obtained in this line of research can be mentioned. First, obedience is more likely when the authority prescribes, regulates, supervises, and administers consequences, rather than only one or some of these options (Rangel-Bernal & Ribes-Iñesta, 2009). Second, in these studies it has been difficult to parse out the effects of compliance from obedience because the researcher is commonly the one providing the request or demand to the participants, which may be perceived inherently as an authority figure. For this reason, these authors have stressed the necessity of further investigating the effects of requests among peers on compliance (Rangel-Bernal et al., 2011).

Sanction Relations Studies

These are the most recent studies and follow the findings from two previous lines of research, particularly concerning the role of consequences in choosing to work under shared contingencies rather than individual ones, and the different ways to administer consequences. This means that sanction relations are examined with respect to the different ways of appropriation of goods and services (exchange relations), as well as to the correspondence between the administration of consequences (power relations), either by the same individual or by individuals external to the contingency, and the prescribed rules to obtain them. Following Ribes-Iñesta et al. (2008), sanctions include reprimand, suspension, expulsion, restitution of property, fine, compensation, reinstatement, cessation, restitution, deprivation of liberty, deprivation of wealth, and the deprivation of life, among others. In short, sanction deals with the rights and obligations of the individuals involved in exchange–power relations. In experimental settings, sanction contingencies are studied in terms of acts of transgression to prescribed norms; wherein, individuals may choose to disregard acts of authority in these studies.

Although few studies concerning sanction relations have been published to date, it is assumed that the different forms of sanction (i.e., authorization, prohibition, and penalization) can be studied in exchange relations (Ribes-Iñesta et al., 2008). In fact, in a study about the effects of individual or common resource availability in choosing individual or shared contingencies, Pulido-Avalos and Ribes-Iñesta (2023) commented that “sharing goods and resources as well as within-group cooperation, may result in increased social altruism, decreasing selfishness and a different conception about rights and obligations in political daily life” (p. 8). This means that different modes to sanction result from production–appropriation relations. It is important to emphasize that sanction as a power relation is always studied in the context of exchange relations. For example, Mérida-Vélez and Pulido-Avalos (2023) studied the effects of different forms of sanction on sharing goods. In particular, the appropriation of common resources among dyads was studied under two conditions: with and without preestablished rules. The rule condition consisted of two subgroups of rules, prohibitive and permissive. Prohibitive rules either forbode appropriation of resources exceeding what the individual can use, or exceeding what the partner has. Permissive rule conditions allowed the appropriation of either from the common pool or from the partner’s pool of puzzle-pieces. Mérida-Vélez and Pulido-Avalos (2023) found that the rules that allowed for appropriation of common resources and prohibited appropriation from their partner’s pool of puzzle pieces were effective in decreasing or completely stopping the individual’s behaviors of appropriating their partner’s resources. The results from this study suggest that interindividual relations can be delimited with the use of preestablished norms.

Although inaction is one possible outcome of incomplete contingencies (Todorov, 2005), from a sociopsychological viewpoint, there are other outcomes related to delimitation of interindividual relations, such as disobedience and impunity. Transgression of norms occurs when contingencies are left unspecified, but these acts can be curtailed using preestablished rules. In short, sanction can be established without the use of consequences contingent upon individual behaviors. Lastly, Mérida-Vélez and Pulido-Avalos (2023) observed that dyadic verbal interactions adjusted to the contingencies at place during the experimental setting, such as conformity to partner’s appropriation of one’s resources and justifications to preestablished norms.

Mérida-Vélez (2019) proposed several research avenues to extend sanction relations studies, listing various sanction parameters that may affect the emergence of different interindividual relations. For example, researchers can explore the role of the individual’s previous history of interaction on establishing episodes of solidarity or generosity, in particular with the incorporation of new individuals into the interindividual relations. Mérida-Vélez also mentions other group of sanction studies that could address the effects of authorization and prohibition of certain behaviors through norms in episodes of theft, bribery, or corruption. Lastly, a third plausible research route mentioned by the author is to study the induction of certain types of verbal interactions in order to favor working under shared contingencies using confederates.

Definitions (5): Theoretical Premises

Sociopsychology (Ribes-Iñesta et al., 2016), as a multidisciplinary extension, is based on a set of assumptions about human behavior and social formations. These assumptions concern the nature and origins of social behavior. In this section we overview three assumptions as a way to round up our discussion of sociopsychology and provide further arguments for the set of definitions outlined above.

Convention

The pivotal difference between sociopsychological events and those studied by the behavior scientist lies in the degree of importance of convention, which enables all human interactions. The “medium of contact,” a term coined by J. R. Kantor (1924–1926), is a factor in psychological events that enables contacts between an individual’s behavior and a stimulus object or event. Said another way, the medium of contact is a category that describes what is possible in a field, which constantly changes from one situation to another. Although Kantor’s (e.g., 1958) medium of contact is defined strictly in terms of physiochemical elements, Ribes-Iñesta and López-Valadez (1985) extended this concept into three types of media: physiochemical (what is feasible), ecological (what is adequate), and conventional (what is pertinent). From this view, human individuals always interact under a conventional medium of contact, so that even nonverbal, motor actions (e.g., seeing) are considered conventional (e.g., seeing data). Therefore, language is not analyzed as morphological verbal acts (e.g., speaking or writing; Skinner, 1957), but rather as that which enables (i.e., a medium) psychological human contacts.

In sociopsychology, convention is of paramount importance, whereas in psychology is significant only in some cases. In other words, psychological events are relatively less dependent upon the conventional structure of a situation than are sociopsychological ones. For example, individual nonhuman organisms can contact stimulus objects and events only under physiochemical and ecological media. For this reason, it is possible to investigate psychological behavior using rats and pigeons. Ribes-Iñesta (2001) argues that the conventional medium is the sole qualitative difference between human social relations and animal groupings, implying that because all human psychological contacts occur under conventional media all social human interactions are inherently conventional.

From an interbehavioral standpoint, that which is social in human relations is not restricted to the presence of another individual (Parrott, 1983); rather, social denotes the conventional structure of the situation under which human interactions occur (Ribes-Iñesta, 2001). Interindividual relations are not mere aggregates of the behavior of two or more individuals, although it is possible to parse out the psychological factors participating therein. For example, Fryling and Hayes (2019) analyzed feelings of closeness and conflict (psychological factors) occurring within romantic relationships (interindividual relations). From the fact that human behavior is a constituent part of social contingencies, it doesn’t follow that social groups are just behavior of individuals. Comparing the behavior of individuals with the behavior between individuals illustrates the mereological fallacy, that is, attributing to a part the properties of the whole system or entity of which it is a component (Ribes-Iñesta et al., 2016). Examples of this sort of fallacy are conceptions of leadership as causes of social change. Leaders are not separate elements from the social organization from which they belong (see Bentley, 1908). In this sense, leadership is not a trait of individuals; rather, it is a trait of the group in which leaders exist. Sociopsychology avoids the mereological fallacy by departing from the notion that individuals oppose groups. As Ribes-Iñesta et al. (2016) point out, the individual does not precede the culture, but rather the culture gives meaning to human individuality.

Emergence of Social Formations

The emergence of social formations as systems of interindividual relations is not biological or rational, but rather they are fundamentally conventional. Social formations as conventional practices emerge from the covivalFootnote 2 rather than the survival of its constituents. Covival is the only qualitative difference between human social formations and other animal social groupings; thus it is important to consider the logical role of covival in analyzing interindividual relations. Social formations emerge from covival when the products of labor exceed individual biological needs. Surplus of production made available the deferred exchange of goods and services between individuals within and between communities and thus social formations emerged from the covival of its members (Ribes-Iñesta, 2023).

The Nature of Social Formations

The matrix of social relations from which any social formation emerges is the division of labor. According to Ribes-Iñesta et al. (2016), “the origin and sustenance of any social formation is based on the organization of collective subsistence, based on the specialization of labor and the deferred distribution of articulated products and services” (p. 17). In sum, social formations are conventional in that they represent a form of living together based on the subsistence of its constituents, (i.e., covival), and they emerge from the deferred exchange of goods and services through division of labor.

Concluding Remarks

At this point, it is relevant to point out some of the outstanding contributions of the sociopsychology of interindividual relations and institutions to behavior scientific knowledge of human behavior and culture. First, the definition of sociopsychology as a multidiscipline sets up, from the start, a clear epistemology as well as the aims of this enterprise. Sociopsychology is not a new science; rather, it is an extension of two sciences. Its aims are those of explaining the behavior between individuals as an irreducible emergent phenomenon located between the psychological event and the social formation. Second, the sociopsychological unit of analysis—that which can be studied under experimental or natural settings—is the interindividual relation, conceived as a segment of institutional practices. The discussion of two types of institutional practices (formal and informal) is necessary insofar as interindividual relations are historically determined, and are not seen as homogenous, universal practices of social formations. As such, social formations are always identified as systems of interindividual relations, changing based on geography, population, available resources, means of production, among other factors (Ribes-Iñesta et al., 2016).

Third, sociopsychology focuses on three dimensions of interindividual relations, namely exchange, power and sanction contingencies. In doing so, a field perspective is adopted to explain the interindividual relation as a field of interrelated exchange, power, and sanction contingencies. This means that production–appropriation, authority–power, and normative delimitation are equal participants in the field, occurring across or diachronic to every interindividual relation as illustrated in Figure 2. The conceptualization of each dimension also offers some insights on what factors beyond delivery of consequences on individual and joint performance can be studied in interindividual relations. These phenomena can be studied in multiple ways, for example, by focusing on tools, available resources, modes of production, among others. Also, power can be studied as more than something individuals produce or exchange (Goltz, 2020) by focusing on the role of authority and the different modes of dominating therein.

Fourth, the method to study interindividual relations provides important advantages: (1) a parsimonious and systematic approach to experimentation and observation, focusing on the manipulation of interrelated factors within a given interindividual dimension; (2) a multifactorial view of changes in interindividual relations, avoiding overemphasis on only one factor, such as earnings or pay offs; (3) allowing individuals to choose between shared or individual contingencies rather than imposing a specific structure under which they must interact; and (4) data collection of interindividual performance in real time, types of verbal interactions, frequency of choosing shared versus individual contingencies. Fifth, from a sociopsychological vantagepoint, culture is not the result from the progressive complexity of human behavior, nor does it represent an autonomous level of selection (Skinner, 1981). Rather, it is the auspices under which social behavior emerges. Thus, comparative studies are inappropriate to study interindividual relations, especially if sanction is the object of analysis because it is exclusively a conventional practice. In general, there is no sociopsychology of animal behavior, only of human practices.

This viewpoint of interindividual relations has two additional implications for any analysis of culture. On one hand, culture does not represent a goal or ultimate end of evolution, it is simply the characteristic structure of human formations and provides the foundation for human psychology writ large. On the other hand, the thesis that division of labor is the central axis of any social formation puts this position at odds with economic-utilitarian studies of social behavior; sociopsychology follows an explicit materialist conception of society elaborated by authors such as Marx and Kropotkin.