Rank, stress, and risk: A conjecture

A perception at the core of studies that consider the link between social rank and stress (typically measured by the so-called stress hormone cortisol) is that the link is direct. Examples of such studies are Bartolomucci (2007), Beery and Kaufer (2015), and Koolhaas et al. (2017). A recent and stark representation of this body of work is a study by Smith-Osborne et al. (2023), who state that "social hierarchies directly influence stress status" (Smith-Osborne et al. p. 1537, italics added). In the present paper, we reflect on this "direct" perspective. We conjecture that the link between social rank and stress involves an intervening variable: an indirect relationship arises when the loss of rank triggers a behavioral response in the form of risk taking aimed at regaining rank, and it is the engagement in risk-taking behavior that is the cause of an elevated level of cortisol. Smith-Osborne et al., as well as others whose papers are cited by Smith-Osborne et al. and who, like Creel (2001) and Avitsur et al. (2006), conducted comprehensive research on the association between rank (social standing) and stress, do not refer to risk taking at all. We present four strands of research that lend support to our conjecture: evidence that in response to losing rank, individuals are stressed; evidence that in response to losing rank, individuals resort to risk-taking behavior aimed at regaining their lost rank; evidence that there exists a link between engagement in risky activities or exposure to risk and elevated levels of cortisol; and an analytical perspective on incidence and intensity, namely a perspective that shows how the willingness to take risks responds to a change in rank, specifically, how a loss of rank triggers a greater willingness to take risks and how this trigger is stronger for individuals whose rank is higher.

Acetylcholine muscarinic M1 receptors in the rodent prefrontal cortex modulate cognitive abilities to establish social hierarchy

In most social species, the attainment of social dominance is strongly affected by personality traits. Dominant individuals show better cognitive abilities, however, whether an individual's cognition can determine its social status has remained inconclusive. We found that mice show better cognitive abilities tend to possess a higher social rank after cohousing. The dynamic release of acetylcholine (ACh) in the prelimbic cortex (PL) is correlated with mouse dominance behavior. ACh enhanced the excitability of the PL neurons via acetylcholine muscarinic M1 receptors (M1). Inhibition of M1 impaired mice cognitive performance and induced losing in social competition. Mice with M1 deficiency in the PL performed worse on cognitive behavioral tests, and exhibited lower status when re-grouped with others. Elevating ACh level in the PL of subordinate mice induced winning. These results provide direct evidence for the involvement of M1 in social hierarchy and suggest that social rank can be tuned by altering cognition through cholinergic system.

Anthropogenic noise limits resource distribution without changing social hierarchies

Increasing evidence demonstrates that anthropogenic noise is a global pollutant that threatens marine ecosystems. Mounting numbers of studies show its diverse effects on individuals and their behaviour. However, little is known about how individual changes in response to anthropogenic noise could cascade through groups and populations affecting resource distribution vital for survival and fitness. Here we test the hypotheses that anthropogenic noise could alter resource distribution, associated hierarchies and consequently individual benefits. We used groups of hermit crabs, a globally distributed model system for assessing impacts of environmental change on wildlife and measured in controlled laboratory conditions the resource distribution of their reusable shelters (gastropod shells) under ship noise and ambient control playbacks. We applied vacancy chain theory to test three predictions about how new resource units create benefits for a population. A new resource unit leads to (i) a cascade of resource abandonments and acquisitions (= chain of vacancy moves) based on an internal (ii) hierarchy (here size-based) which allows (iii) more than one individual to benefit. All three predictions were supported under control sound. Under anthropogenic noise however, fewer individuals benefitted from the arrival of a new, empty shell, while the size-based hierarchy was maintained. The latter was apparent in chain structures, which were concordant between sound treatments. This experiment shows that anthropogenic noise can affect individual behaviours that cascade through groups. This has the potential to disrupt wider resource distribution in populations.

Transcranial direct current stimulation suggests a causal role of the medial prefrontal cortex in learning social hierarchy

Social hierarchies can be inferred through observational learning of social relationships between individuals. Yet, little is known about the causal role of specific brain regions in learning hierarchies. Here, using transcranial direct current stimulation, we show a causal role of the medial prefrontal cortex (mPFC) in learning social versus non-social hierarchies. In a Training phase, participants acquired knowledge about social and non-social hierarchies by trial and error. During a Test phase, they were presented with two items from hierarchies that were never encountered together, requiring them to make transitive inferences. Anodal stimulation over mPFC impaired social compared with non-social hierarchy learning, and this modulation was influenced by the relative social rank of the members (higher or lower status). Anodal stimulation also impaired transitive inference making, but only during early blocks before learning was established. Together, these findings demonstrate a causal role of the mPFC in learning social ranks by observation.

Transcriptional programming of social hierarchy

In this issue of Neuron, Choi and colleagues1 uncover the direct role of the transcription factor Pou3f1 in regulating dominance hierarchy in mice. Pou3f1 accomplishes this role via its action in specific prefrontal projection neurons that regulate behaviors associated with low social status.

Self- and Other-Orientation in High Rank: A Cultural Psychological Approach to Social Hierarchy

PUBLIC ABSTRACT

Social hierarchy is one fundamental aspect of human life, structuring interactions in families, teams, and entire societies. In this review, we put forward a new theory about how social hierarchy is shaped by the wider societal contexts (i.e., cultures). Comparing East Asian and Western cultural contexts, we show how culture comprises societal beliefs about who can raise to high rank (e.g., become a leader), shapes interactions between high- and low-ranking individuals (e.g., in a team), and influences human thought and behavior in social hierarchies. Overall, we find cultural similarities, in that high-ranking individuals are agentic and self-oriented in both cultural contexts. But we also find important cross-cultural differences. In East Asian cultural contexts, high-ranking individuals are also other oriented; they are also concerned about the people around them and their relationships. We close with a call to action, suggesting studying social hierarchies in more diverse cultural contexts.

Inferior social hierarchy is vulnerable to anxiety-like behavior in chronic pain mice: Potential role of gut microbiota and metabolites

Social dominance is a universal phenomenon among grouped animals that profoundly affects survival, health, and reproductive success by determining access to resources, and exerting a powerful influence on subsequent behavior. However, the understanding of pain and anxiety comorbidities in dominant or subordinate animals suffering from chronic pain is not well-defined. Here, we provide evidence that subordinate mice are more susceptible to pain-induced anxiety compared to dominant mice. We propose that the gut microbiota may play a mediating role in this mechanism. Our findings demonstrate that transplantation of fecal microbiota from subordinate mice with chronic inflammatory pain, but not dominant mice, into antibiotics-treated pseudo-germ-free mice significantly amplifies anxiety-like phenotypes, highlighting the critical involvement of gut microbiota in this behavioral response. Using chronic inflammatory pain model, we carried out 16S rRNA sequencing and untargeted metabolomic analyses to explore the relationship between microbiota and metabolites in a stable social hierarchy of mice. Interestingly, anxiety-like behaviors were directly associated with some microbial genera and metabolites, especially bile acid metabolism. Overall, we have demonstrated a close relationship between social status and anxiety susceptibility, highlighting the contributions of gut microbiota and the associated metabolites in the high-anxiety state of subordinate mice with chronic inflammatory pain.

The impact of social hierarchies on neural response to feedback evaluations after advice giving

Advisors generally evaluate advisee-relevant feedback after advice giving. The response to these feedback-(1) whether the advice is accepted and (2) whether the advice is optimal-usually involves prestige. Prior literature has found that prestige is the basis by which individuals attain a superior status in the social hierarchy. However, whether advisors are motivated to attain a superior status when engaging in advice giving remains uncharacterized. Using event-related potentials, this study investigates how advisors evaluate feedback after giving advice to superior (vs. inferior) status advisees. A social hierarchy was first established based on two advisees (one was ranked as superior status and another as inferior status) as well as participants' performance in a dot-estimation task in which all participants were ranked as medium status. Participants then engaged in a game in which they were assigned roles as advisors to a superior or inferior status advisee. Afterward, the participants received feedback in two phases. In Phase 1, participants were told whether the advisees accepted the advice provided. In Phase 2, the participants were informed whether the advice they provided was correct. In these two phases, when the advisee was of superior status, participants exhibited stronger feedback-related negativity and P300 difference in response to (1) whether their advice was accepted, and (2) whether their advice was correct. Moreover, the P300 was notably larger when the participants' correct advice led to a gain for a superior-status advisee. In the context of advice giving, advisors are particularly motivated to attain a superior status when the feedback involving social hierarchies, which is reflected in higher sensitivity to feedback associated with superior status advisees at earlier and later stages during feedback evaluations in brains.

Characterization of social hierarchy formation and maintenance in same-sex, group-housed male and female C57BL/6 J mice

Social hierarchies are a prevalent feature of all animal groups, and an individual's rank within the group can significantly affect their overall health, typically at the greatest expense of the lowest-ranked individuals, or omegas. These subjects have been shown to exhibit various stress-related phenotypes, such as increased hypothalamic-pituitary axis activity and increased amygdalar corticotropin-releasing factor levels compared to higher-ranked subjects. However, these findings have been primarily characterized in males and in models requiring exhibition of severe aggression. The goals of the current study, therefore, were to characterize the formation and maintenance of social hierarchies using the tube test and palatable liquid competition in same-sex groups of male and female C57BL/6 J mice. We also aimed to examine the effects of tube test-determined social rank on plasma and hypothalamic oxytocin and vasopressin levels, peptides with established roles in social behaviors and the stress response. Lastly, we assessed the effects of environmental enrichment and length of testing on the measures outlined above. Overall, we demonstrated that males and females develop social hierarchies and that these hierarchies can be determined using the tube test. While we were unable to establish a consistent connection between peptide levels and social rank, we observed transient changes in these peptides reflecting complex interactions between social rank, sex, environment, and length of testing. We also found that many male and female omegas began to exhibit passive coping behavior after repeated tube test losses, demonstrating the potential of this assay to serve as a model of chronic, mild psychosocial stress.

The role of legitimizing the social hierarchy in the impact of status on perceived assertiveness and competence

The present research aimed to examine how perceivers' system-justifying beliefs moderate the way they evaluate high- versus low-status targets on assertiveness and competence. In three experimental studies, we manipulated a target's hierarchical position within his company's organization. Participants rated the target on traits reflecting assertiveness and competence. Their system-justifying beliefs were assessed in an ostensibly unrelated study. Results consistently showed that participants inferred assertiveness from the target's hierarchical position regardless of system justification, whereas the relationship between social status and competence was consistently moderated by system-justifying beliefs: only participants high in system justification ascribed more competence to the high-status target than to the low-status target. These findings are in line with the hypothesis suggesting that inferring competence from high-status positions could rely on the tendency to justify social inequalities, whereas inferring assertiveness would not.

Dopamine D2 receptor within the intermediate region of the lateral septum modulate social hierarchy in male mice

The dopamine (DA) system has long been involved in social hierarchies; however, the specific mechanisms have not been elucidated. The lateral septum (LS) is a limbic brain structure that regulates various emotional, motivational, and social behaviors. DA receptors are abundantly expressed in the LS, modulating its functions. In this study, we evaluated the functions of DA receptors within different subregions of the LS in social dominance using a confrontation tube test in male mice. The results showed that mice living in social groups formed linear dominance hierarchies after a few days of cohousing, and the subordinates showed increased anxiety. Fos expressions was elevated in the entire LS after a confrontation tube test in the subordinates. However, DA neurons were more activated in the dominates within the ventral tegmental area and the dorsal raphe nucleus. Quantitative real-time polymerase chain reaction results showed that D2 receptor (D2R) within the intermediate region of the LS (LSi) were elevated in the subordinate. In the following pharmacological studies, we found simultaneous D2R activation in the dominants and D2R inhibition in the subordinates switched the original dominant-subordinate relationship. The aforementioned results suggested that D2R within the LSi plays an important role in social dominance in male mice. These findings improve our understanding of the neural mechanisms underlying the social hierarchy, which is closely related to our social life and happiness.

Neural tracking of social hierarchies in adolescents' real-world social networks

In the current study, we combined sociometric nominations and neuroimaging techniques to examine adolescents' neural tracking of peers from their real-world social network that varied in social preferences and popularity. Adolescent participants from an entire school district (N = 873) completed peer sociometric nominations of their grade at school, and a subset of participants (N = 117, Mage = 13.59 years) completed a neuroimaging task in which they viewed peer faces from their social networks. We revealed two neural processes by which adolescents track social preference: (1) the fusiform face area, an important region for early visual perception and social categorization, simultaneously represented both peers high in social preference and low in social preference; (2) the dorsolateral prefrontal cortex (DLPFC), which was differentially engaged in tracking peers high and low in social preference. No regions specifically tracked peers high in popularity and only the inferior parietal lobe, temporoparietal junction, midcingulate cortex and insula were involved in tracking unpopular peers. This is the first study to examine the neural circuits that support adolescents' perception of peer-based social networks. These findings identify the neural processes that allow youths to spontaneously keep track of peers' social value within their social network.

5-HT1A receptor in the central amygdala and 5-HT2A receptor in the basolateral amygdala are involved in social hierarchy in male mice

Most social animals self-organize into dominance hierarchies that strongly influence their behavior and health. The serotonin (5-HT) system is believed to play an important role in the formation of social hierarchy. 5-HT receptors are abundantly expressed in the amygdala, which is considered as the central node for the perception and learning of social hierarchy. In this study, we assessed the functions of various 5-HT receptor subtypes related to social rank determination in different subregions of the amygdala using the confrontation tube test in mice. We revealed that most adult C57BL/6 J male mice exhibited a linear social rank after a few days of cohousing. The tube test ranks were slightly related to anxiety-like behavioral performance. After the tube test, the amygdala and 5-HT neurons in the dorsal raphe nucleus were activated in lower-rank individuals. Quantitative real-time polymerase chain reaction analysis revealed that despite the high expression of 5-HT1A receptor mRNA in the central amygdala (CeA), 5-HT2A receptor mRNA expression was downregulated in the basolateral amygdala (BLA) in higher-rank individuals. The dominant-subordinate relationship between mouse pairs could be switched via pharmacological modulation of these receptors in CeA and BLA, suggesting that these expression changes are essential for establishing social ranks. Our findings provide novel insights into the divergent functions of 5-HT receptors in the amygdala related to social hierarchy, which is closely related to our health and welfare.

Distinctive Roles of Medial Prefrontal Cortex Subregions in Strategic Conformity to Social Hierarchy

People often align their behaviors and decisions with others' expectations, especially those of higher social positions, when they are being observed. However, little attention has been paid to the neural mechanisms underlying increased conformity to the social hierarchy under social observation. Using a preference rating task, we investigated whether and how individual preferences for novel stimuli were influenced by others' preferences by manipulating others' social hierarchy and observational context. The behavioral results showed that human participants of both sexes were more likely to change their preferences to match those of a superior partner in a public than in a private context. fMRI data revealed distinct contributions of the subregions of the medial prefrontal cortex (mPFC) to increased conformity to social hierarchy under observation. Specifically, the ventral mPFC showed increased activity when participants' preferences aligned with those of superior partners, regardless of behavioral manifestation. The rostral mPFC showed increased activity when conforming to a superior partner and nonconforming to an inferior one, indicating goal-dependent valuation. The dorsal mPFC showed increased activity in private conditions with a superior partner but only in those with a higher tendency to conform. These findings support the hierarchical allostatic regulation model of the mPFC function for social valuation and suggest strategic conformity as a way to minimize metabolic costs.SIGNIFICANCE STATEMENT This study revealed distinct roles of subregions of the mPFC in increased conformity to individuals of different social ranks under observation. Specifically, the ventral mPFC showed increased activity when participants' preferences aligned with those of higher-ranking partners, whereas the rostral mPFC showed increased activity when conforming to a superior partner and nonconforming to an inferior partner, indicating goal-dependent valuation. The dorsal mPFC was more active in private conditions with a superior partner but only in those with a higher tendency to conform. These findings support the hierarchical allostatic regulation model of the mPFC function for social valuation and suggest strategic conformity as a way to minimize metabolic costs.

Quantifying agonistic interactions between group-housed animals to derive social hierarchies using computer vision: a case study with commercially group-housed rabbits

In recent years, computer vision has contributed significantly to the study of farm animal behavior. In complex environments such as commercial farms, however, the automated detection of social behavior and specific interactions between animals can be improved. The present study addresses the automated detection of agonistic interactions between caged animals in a complex environment, relying solely on computer vision. An automated pipeline including group-level temporal action segmentation, object detection, object tracking and rule-based action classification for the detection of agonistic interactions was developed and extensively validated at a level unique in the field. Comparing with observations made by human observers, our pipeline reaches 77% precision and 85% recall using a 5-min tolerance interval for the detection of agonistic interactions. Results obtained using this pipeline allow to construct time-dependent socio-matrices of a group of animals and derive metrics on the dominance hierarchy in a semi-automated manner. Group-housed breeding rabbits (does) with their litters in commercial farms are the main use-case in this work, but the idea is probably also applicable to other social farm animals.

Human and animal dominance hierarchies show a pyramidal structure guiding adult and infant social inferences

This study investigates the structure of social hierarchies. We hypothesized that if social dominance relations serve to regulate conflicts over resources, then hierarchies should converge towards pyramidal shapes. Structural analyses and simulations confirmed this hypothesis, revealing a triadic-pyramidal motif across human and non-human hierarchies (114 species). Phylogenetic analyses showed that this pyramidal motif is widespread, with little influence of group size or phylogeny. Furthermore, nine experiments conducted in France found that human adults (N = 120) and infants (N = 120) draw inferences about dominance relations that are consistent with hierarchies' pyramidal motif. By contrast, human participants do not draw equivalent inferences based on a tree-shaped pattern with a similar complexity to pyramids. In short, social hierarchies exhibit a pyramidal motif across a wide range of species and environments. From infancy, humans exploit this regularity to draw systematic inferences about unobserved dominance relations, using processes akin to formal reasoning.

Flattening Hierarchical Structures to Empower Women Trainee Leaders on Social Media Teams

We share our experience empowering women trainees and leadership through a flattened hierarchical social media team structure with supporting evidence from measurable outcomes.

Female dominance hierarchies influence responses to psychosocial stressors

Social species form dominance hierarchies to ensure survival and promote reproductive success. Traditionally studied in males, rodent hierarchies are considered despotic, and dominant social rank results from a history of winning agonistic encounters. By contrast, female hierarchies are thought to be less despotic, and rank is conferred by intrinsic traits. Both social buffering and elevated social status confer resilience to depression, anxiety, and other consequences of chronic stress. Here, we investigate whether female social hierarchies and individual traits related to social rank likewise influence stress resilience. We observe the formation of dyadic female hierarchies under varying conditions of ambient light and circadian phase and subject mice to two forms of chronic psychosocial stress: social isolation or social instability. We find that stable female hierarchies emerge rapidly in dyads. Individual behavioral and endocrinological traits are characteristic of rank, some of which are circadian phase dependent. Further, female social rank is predicted by behavior and stress status prior to social introduction. Other behavioral characteristics suggest that rank is motivation-based, indicating that female rank identity serves an evolutionarily relevant purpose. Rank is associated with alterations in behavior in response to social instability stress and prolonged social isolation, but the different forms of stress produce disparate rank responses in endocrine status. Histological examination of c-Fos protein expression identified brain regions that respond to social novelty or social reunion following chronic isolation in a rank-specific manner. Collectively, female rank is linked to neurobiology, and hierarchies exert context-specific influence upon stress outcomes.

Are infrared thermography, feeding behavior, and heart rate variability measures capable of characterizing group-housed sow social hierarchies?

Group gestation housing is quickly becoming standard practice in commercial swine production. However, poor performance and welfare in group housed sows may result from the formation and maintenance of the social hierarchy within the pen. In the future, the ability to quickly characterize the social hierarchy via precision technologies could be beneficial to producers for identifying animals at risk of poor welfare outcomes. Therefore, the objective of this study was to investigate the use of infrared thermography (IRT), automated electronic sow feeding systems, and heart rate monitors as potential technologies for detecting the social hierarchy within five groups of sows. Behavioral data collection occurred for 12 h after introducing five sow groups (1-5; n = 14, 12, 15, 15, and 17, respectively) to group gestation housing to determine the social hierarchy and allocate individual sows to 1 of 4 rank quartiles (RQ 1-4). Sows within RQ1 were ranked highest while RQ4 sows were ranked lowest within the hierarchy. Infrared thermal images were taken behind the neck at the base of the ear of each sow on days 3, 15, 30, 45, 60, 75, 90, and 105 of the experiment. Two electronic sow feeders tracked feeding behavior throughout the gestation period. Heart rate monitors were worn by 10 randomly selected sows per repetition for 1 h prior to and 4 h after reintroduction to group gestation housing to collect heart rate variability (HRV). No differences were found between RQ for any IRT characteristic. Sows within RQ3 and RQ4 had the greatest number of visits to the electronic sow feeders overall (P < 0.04) but spent shorter time per visit in feeders (P < 0.05) than RQ1 and RQ2 sows. There was an interaction of RQ with hour for feed offered (P = 0.0003), with differences between RQ occurring in hour 0, 1, 2, and 8. Higher-ranked sows (RQ1 and RQ2) occupied the feeder for longer during the first hour than lower ranking sows (RQ3 and RQ4; P < 0.04), while RQ3 sows occupied the feeder longer than RQ1 sows during hour 6, 7, and 8 (P < 0.02). Heart beat interval (RR) collected prior to group housing introduction differed between RQ (P < 0.02 for all), with RQ3 sows exhibiting the lowest RR, followed by RQ4, RQ1, and RQ2. Rank quartile also affected standard deviation of RR (P = 0.0043), with RQ4 sows having the lowest, followed by RQ1, RQ3, and RQ2 sows. Overall, these results indicate that feeding behavior and HRV measures may be capable of characterizing social hierarchy in a group housing system.

Texts, Practice and Practitioners: Computational Cultures at Work in Early Modern South India

This essay will discuss the hegemonic role that texts have come to play in the historiography of subcontinental mathematical traditions. It will argue that texts need to be studied as records of practices of people's working lives, grounded in social hierarchies. We will take particular mathematical texts to show how different occupational registers have come to shape practices that defy the binaries of concrete and abstract, high and low mathematics or the pure and applied conundrum. Measuring, counting and accounting practices as part of the routine work of practitioners performing their caste occupations then provide us with a spectrum of the computational activities that controlled and regulated the lives of people in the past. In the process the act of computing itself gained certain political values such as cunning and manipulation, identified with professions of village accountant and merchant, for example. Drawn from my earlier work on these records, I discuss the occupational role of the accountant as a political functionary who assessed and authenticated the measurements of land and produce in the village, making values of the labor performed by others, and creating avenues for his own proficiency as a mathematical practitioner.

Prestige Orientation and Reconciliation in the Workplace

Human social hierarchies comprise two distinct bases of status: dominance and prestige. One can acquire high social status not only by physically intimidating others (dominance) but also by providing information goods to others (prestige). Given that prestige-oriented individuals need to be liked and accepted by others, we hypothesized that they would be more eager to reconcile with their coworkers when they were involved in interpersonal conflicts in their workplaces. Study 1 asked 487 respondents about their conciliatory behaviors in response to workplace conflicts. Prestige-oriented individuals were more apologetic (when they hurt someone in their workplace) and forgiving (when they were hurt by someone). However, analyses of a subsample of respondents who had conflicts with their followers showed that organizational leaders' prestige orientation was associated only with forgiveness but not with apologetic behavior. Study 2 collected comparable data from 678 organizational leaders. Study 2 confirmed the results of the subsample analysis of Study 1. Compared with leaders low in prestige orientation, leaders high in prestige orientation were more likely to forgive their subordinates; however, they were no more likely to apologize to their subordinates.

The social hierarchical restrictions of Chinese verbs rapidly guide online thematic role assignment in comprehension

The information about social hierarchical relationship has been intrinsically embedded into semantic restrictions of some Chinese verbs theoretically. For example, the Chinese verb ''(shanyang, support: provide for the needs and comfort of one's elders) only allows its Agent role to have a lower social status compared to the Patient role. However, whether this hierarchical restriction can be rapidly activated and how it impacts online thematic role assignment in reading remains to be seen. To answer this question, a 2 (Verb Type: hierarchical vs non-hierarchical verbs) × 2 (Social Hierarchy Sequence: match vs mismatch) design was constructed in the present study to investigate the interaction between the two factors. ERPs showed that hierarchical restriction violations evoked a stronger anterior negativity to the sentence-final noun (NP2). This effect was absent under two non-hierarchical conditions. To our knowledge, this study is the first to reveal that social hierarchical restrictions of Chinese hierarchical verbs can be rapidly available to guide online thematic role assignment and this process might be closely related to readers' thematic role knowledge.

socialh: An R package for determining the social hierarchy of animals using data from individual electronic bins

Cattle have a complex social organization, with negative (agonistic) and positive (affiliative) interactions that affect access to environmental resources. Thus, the social behaviour has a major impact on animal production, and it is an important factor to improve the farm animal welfare. The use of data from electronic bins to determine social competition has already been validated; however, the studies used non-free software or did not make the code available. With data from electronic bins is possible to identify when one animal takes the place of another animal, i.e. a replacement occurs, at the feeders or drinkers. However, there is no package for the R environment to detect competitive replacements from electronic bins data. Our general approach consisted in creating a user-friendly R package for social behaviour analysis. The workflow of the socialh package comprises several steps that can be used sequentially or separately, allowing data input from electronic systems, or obtained from the animals’ observation. We provide an overview of all functions of the socialh package and demonstrate how this package can be applied using data from electronic feed bins of beef cattle. The socialh package provides support for researchers to determine the social hierarchy of gregarious animals through the synthesis of agonistic interactions (or replacement) in a friendly, versatile, and open-access system, thus contributing to scientific research.

Expanding the frame around social dynamics and glucocorticoids: From hierarchies within the nest to competitive interactions among species

The effect of the social environment on individual state or condition has largely focused on glucocorticoid levels (GCs). As metabolic hormones whose production can be influenced by nutritional, physical, or psychosocial stressors, GCs are a valuable (though singular) measure that may reflect the degree of "stress" experienced by an individual. Most work to date has focused on how social rank influences GCs in group-living species or how predation risk influences GCs in prey. This work has been revealing, but a more comprehensive assessment of the social environment is needed to fully understand how different features of the social environment influence GCs in both group living and non-group living species and across life history stages. Just as there can be intense within-group competition among adult conspecifics, it bears appreciating there can also be competition among siblings from the same brood, among adult conspecifics that do not live in groups, or among heterospecifics. In these situations, dominance hierarchies typically emerge, albeit, do dominants or subordinate individuals or species have higher GCs? We examine the degree of support for hypotheses derived from group-living species about whether differential GCs between dominants and subordinates reflect the "stress of subordination" or "costs of dominance" in these other social contexts. By doing so, we aim to test the generality of these two hypotheses and propose new research directions to broaden the lens that focuses on social hierarchies and GCs.

Children's thinking about group-based social hierarchies

Wealth, power, and status are distributed unevenly across social groups. A surge of recent research reveals that people being recognizing, representing, and reasoning about group-based patterns of inequity during the first years of life. We first synthesize recent research on what children learn about group-based social hierarchies as well as how this learning occurs. We then discuss how children not only learn about societal structures but become active participants in them. Studying the origins and development of children's thoughts and behavior regarding group-based social hierarchies provides valuable insight into how systems of inequity are perpetuated across generations and how intergroup biases related to wealth, power, and status may be mitigated and reshaped early in development.

Memory bias for social hierarchical information is modulated by perceived social rank

Hierarchies pervade human society, characterising its members along diverse dimensions ranging from their abilities or skills in a particular domain to their economic status or physical stature. One intriguing aspect of the centrality of hierarchies, relative to egalitarian constructs, is that hierarchically-organised social information appears to be remembered more easily than non-hierarchically-organised information. However, it is not yet clear how one's social rank within a hierarchy influences processing. In a pre-registered study with 66 healthy participants, we examined memory recall for hierarchical information when participants themselves were positioned higher in the hierarchy versus lower in the hierarchy, both relative to an egalitarian control condition. The results replicate previous work showing that hierarchical information is memorised faster relative to the egalitarian control. Importantly, this effect was modulated by the participant's position within the hierarchy, with higher positioned participants memorising information faster than lower-positioned participants. This study provides new evidence showing biases in memory will favour hierarchical information if modulated by perceptions of one's own social rank.

Endocrine and neuroendocrine regulation of social status in cichlid fishes

Position in a dominance hierarchy profoundly impacts group members' survival, health, and reproductive success. Thus, understanding the mechanisms that regulate or are associated with an individuals' social position is important. Across taxa, various endocrine and neuroendocrine signaling systems are implicated in the control of social rank. Cichlid fishes, with their often-limited resources of food, shelter, and mates that leads to competition, have provided important insights on the proximate and ultimate mechanisms related to establishment and maintenance of dominance hierarchies. Here we review the existing information on the relationships between endocrine (e.g., circulating hormones, gonadal and other tissue measures) and neuroendocrine (e.g., central neuropeptides, biogenic amines, steroids) systems and dominant and subordinate social rank in male cichlids. Much of the current literature is focused on only a few representative cichlids, particularly the African Astatotilapia burtoni, and several other African and Neotropical species. Many hormonal regulators show distinct differences at multiple biological levels between dominant and subordinate males, but generalizations are complicated by variations in experimental paradigms, methodological approaches, and in the reproductive and parental care strategies of the study species. Future studies that capitalize on the diversity of hierarchical structures among cichlids should provide insights towards better understanding the endocrine and neuroendocrine mechanisms contributing to social rank. Further, examination of this topic in cichlids will help reveal the selective pressures driving the evolution of endocrine-related phenotypic traits that may facilitate an individual's ability to acquire and maintain a specific social rank to improve survival and reproductive success.

Manifestations of domination: Assessments of social dominance in rodents

Social hierarchies are ubiquitous features of virtually all animal groups. The varying social ranks of members within these groups have profound effects on both physical and emotional health, with lower-ranked individuals typically being the most adversely affected by their respective ranks. Thus, reliable measures of social dominance in preclinical rodent models are necessary to better understand the effects of an individual's social rank on other behaviors and physiological processes. In this review, we outline the primary methodologies used to assess social dominance in various rodent species: those that are based on analyses of agonistic behaviors, and those that are based on resource competition. In synthesizing this review, we conclude that assays based on resource competition may be better suited to characterize social dominance in a wider variety of rodent species and strains, and in both males and females. Lastly, albeit expectedly, we demonstrate that similarly to many other areas of preclinical research, studies incorporating female subjects are lacking in comparison to those using males. These findings emphasize the need for an increased number of studies assessing social dominance in females to form a more comprehensive understanding of this behavioral phenomenon.

Social hierarchies and social networks in humans

Across species, social hierarchies are often governed by dominance relations. In humans, where there are multiple culturally valued axes of distinction, social hierarchies can take a variety of forms and need not rest on dominance relations. Consequently, humans navigate multiple domains of status, i.e. relative standing. Importantly, while these hierarchies may be constructed from dyadic interactions, they are often more fundamentally guided by subjective peer evaluations and group perceptions. Researchers have typically focused on the distinct elements that shape individuals' relative standing, with some emphasizing individual-level attributes and others outlining emergent macro-level structural outcomes. Here, we synthesize work across the social sciences to suggest that the dynamic interplay between individual-level and meso-level properties of the social networks in which individuals are embedded are crucial for understanding the diverse processes of status differentiation across groups. More specifically, we observe that humans not only navigate multiple social hierarchies at any given time but also simultaneously operate within multiple, overlapping social networks. There are important dynamic feedbacks between social hierarchies and the characteristics of social networks, as the types of social relationships, their structural properties, and the relative position of individuals within them both influence and are influenced by status differentiation. This article is part of the theme issue 'The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies'.

Neural systems that facilitate the representation of social rank

Across species, animals organize into social dominance hierarchies that serve to decrease aggression and facilitate survival of the group. Neuroscientists have adopted several model organisms to study dominance hierarchies in the laboratory setting, including fish, reptiles, rodents and primates. We review recent literature across species that sheds light onto how the brain represents social rank to guide socially appropriate behaviour within a dominance hierarchy. First, we discuss how the brain responds to social status signals. Then, we discuss social approach and avoidance learning mechanisms that we propose could drive rank-appropriate behaviour. Lastly, we discuss how the brain represents memories of individuals (social memory) and how this may support the maintenance of unique individual relationships within a social group. This article is part of the theme issue 'The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies'.

Behavioural and physiological plasticity in social hierarchies

Individuals occupying dominant and subordinate positions in social hierarchies exhibit divergent behaviours, physiology and neural functioning. Dominant animals express higher levels of dominance behaviours such as aggression, territorial defence and mate-guarding. Dominants also signal their status via auditory, visual or chemical cues. Moreover, dominant animals typically increase reproductive behaviours and show enhanced spatial and social cognition as well as elevated arousal. These biobehavioural changes increase energetic demands that are met via shifting both energy intake and metabolism and are supported by coordinated changes in physiological systems including the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes as well as altered gene expression and sensitivity of neural circuits that regulate these behaviours. Conversely, subordinate animals inhibit dominance and often reproductive behaviours and exhibit physiological changes adapted to socially stressful contexts. Phenotypic changes in both dominant and subordinate individuals may be beneficial in the short-term but lead to long-term challenges to health. Further, rapid changes in social ranks occur as dominant animals socially ascend or descend and are associated with dynamic modulations in the brain and periphery. In this paper, we provide a broad overview of how behavioural and phenotypic changes associated with social dominance and subordination are expressed in neural and physiological plasticity. This article is part of the theme issue 'The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies'.

Children's inequality aversion in intergroup contexts: The role of parents' social dominance orientation, right-wing authoritarianism and moral foundations

Although children are overall sensitive to inequality and prefer fair allocation of resources, they also often display ingroup favouritism. Inquiring about the factors that can shape the tension between these two driving forces in children, we focused on the role of parents. Extending the limited literature in this field, the present work examined whether individual differences in 3-to 11-year-old White children’s (N = 154, 78 boys) evaluations of fair versus pro-ingroup behaviours in an intergroup context vary as a function of both mothers’ and fathers’ social dominance orientation (SDO), right-wing authoritarianism (RWA), and moral foundations. Parents completed a questionnaire. Children were presented with a scenario in which two ingroup members distributed candies to two other children, one White and one Black, either in an egalitarian way or displaying a clear ingroup favouritism. Afterwards, their attitudes towards the two ingroup members who had distributed the candies were assessed through both an Implicit Association Test and explicit questions. Although children displayed on average an explicit preference for the fair over the pro-ingroup target, this preference did not emerge at the implicit level. Most importantly, both children’s explicit and implicit attitudes were related to mothers’ SDO, indicating that at increasing level of mothers’ SDO children’s inequality aversion tended to drop. Overall, these results emphasize the relevance of mothers’ support for social hierarchy in relation to the way in which children balance the two competing drives of equality endorsement and pro-ingroup bias.

Eusociality is linked to caste-specific differences in metabolism, immune system, and somatic maintenance-related processes in an ant species

The social organization of many primate, bird and rodent species and the role of individuals within that organization are associated with specific individual physiological traits. However, this association is perhaps most pronounced in eusocial insects (e.g., termites, ants). In such species, genetically close individuals show significant differences in behavior, physiology, and life expectancy. Studies addressing the metabolic changes according to the social role are still lacking. We aimed at understanding how sociality could influence essential molecular processes in a eusocial insect, the black garden ant (Lasius niger) where queens can live up to ten times longer than workers. Using mass spectrometry-based analysis, we explored the whole metabolome of queens, nest-workers and foraging workers. A former proteomics study done in the same species allowed us to compare the findings of both approaches. Confirming the former results at the proteome level, we showed that queens had fewer metabolites related to immunity. Contrary to our predictions, we did not find any metabolite linked to reproduction in queens. Among the workers, foragers had a metabolic signature reflecting a more stressful environment and a more highly stimulated immune system. We also found that nest-workers had more digestion-related metabolites. Hence, we showed that specific metabolic signatures match specific social roles. Besides, we identified metabolites differently expressed among behavioral castes and involved in nutrient sensing and longevity pathways (e.g., sirtuins, FOXO). The links between such molecular pathways and aging being found in an increasing number of taxa, our results confirm and strengthen their potential universality.

Eigenvector centrality defines hierarchy and predicts graduation in therapeutic community units

INTRODUCTION

Therapeutic communities (TCs) are mutual aid based residential programs for the treatment of substance abuse and criminal behavior. While it is expected that residents will provide feedback to peers, there has been no social network study of the hierarchy through which feedback flows.

METHODS

Data for this study was drawn from clinical records of peer corrections exchanged between TC residents in six units kept over periods of less than two to over eight years. Four of the units served men while two served women. Hierarchy position was measured using eigenvector centrality, on the assumption that residents who were more central in the network of corrections were lower in the hierarchy. It was hypothesized that residents would rise in the hierarchy over time. This was tested using Wilcoxon paired samples tests comparing the mean and maximum eigenvector centrality for time in treatment with those in the last month of treatment. It was also hypothesized that residents who rose higher in the hierarchy were more likely to graduate, the outcome of primary interest. Logistic regression was used to test hierarchy position as a predictor of graduation, controlling for age, race, risk of recidivism as measured by the Level of Services Inventory-Revised (LSI-R) and days spent in the program.

RESULTS

Residents averaged a statistically significantly lower eigenvector centrality in the last month in all units, indicating a rise in the hierarchy over time. Residents with lower maximum and average eigenvector centrality both over the length of treatment and in the last month of treatment were more likely to graduate in four of the six units, those with lower maximum and average eigenvector centrality in the last month but not over the length of treatment were more likely to graduate in one of the six units, while eigenvector centrality did not predict graduation in one unit. However, this last unit was much smaller than the others, which may have influenced the results.

CONCLUSION

These results suggest that TC residents move through a social network hierarchy and that movement through the hierarchy predicts successful graduation.

Group size, temperature and body size modulate the effects of social hierarchy on basal cortisol levels in fishes

Social rank in a structured society has been linked to basal levels of glucocorticoids in various species, with dominant individuals generally presenting lower levels than subordinates. The biotic and abiotic factors influencing glucocorticoids levels across social ranks are still, however, unclear in fishes. We investigated the influences of group size, fish size, sex, age, and reproduction type, plus water salinity and temperature, on the basal levels of cortisol, the major stress hormone in fishes. A phylogenetically controlled meta-analysis was performed on data from 72 studies over 22 species of fishes. As expected, dominants generally exhibited lower levels of cortisol than subordinates. More importantly, the strength of the correlation between cortisol and rank was modulated by three main factors, group size, environmental temperature, and fish size. Differences in basal cortisol between dominants and subordinates were significantly greater in small groups (dyadic contexts) when compared to larger groups. Differences between dominants and subordinates were also greater in temperate regions when compared to the tropics, and in species with larger body size. These results provide valuable insights into the links among hierarchy, stress and metabolism in fishes.

Conspicuous corruption: Evidence at a country level

People can exhibit their status by the consumption of particular goods or experiential purchases; this is known as "conspicuous consumption"; the practice is widespread and explains the market characteristics of a whole class of goods, Veblen goods, demand for which increase in tandem with their price. The value of such positional goods lies in their distribution among the population-the rarer they are, the more desirable they become. At the same time, higher income, often associated with higher status, has been studied in its relation to unethical behavior. Here we present research that shows how a particular Veblen good, illicit behavior, and wealth, combine to produce the display of illegality as a status symbol. We gathered evidence at a large, country-level, scale of a particular form of consumption of an illictly acquired good for status purposes. We show that in Greece, a developed middle-income country, where authorities cannot issue custom vanity license plates, people acquire distinguishing plate numbers that act as vanity plate surrogates. We found that such license plates are more common in cars with bigger engines and in luxury brands, and are therefore associated with higher value vehicles. This cannot be explained under the lawful procedures for allocating license plates and must therefore be the result of illegal activities, such as graft. This suggests a pattern of "conspicuous corruption", where individuals break the law and use their gains as status symbols, knowing that the symbols hint at rule-breaking, as long as the unlawful practice cannot be incontestably established.

A network formation game for the emergence of hierarchies

We propose a novel network formation game that explains the emergence of various hierarchical structures in groups where self-interested or utility-maximizing individuals decide to establish or severe relationships of authority or collaboration among themselves. We consider two settings: we first consider individuals who do not seek the other party's consent when establishing a relationship and then individuals who do. For both settings, we formally relate the emerged hierarchical structures with the novel inclusion of well-motivated hierarchy promoting terms in the individuals' utility functions. We first analyze the game via a static analysis and characterize all the hierarchical structures that can be formed as its solutions. We then consider the game played dynamically under stochastic interactions among individuals implementing better-response dynamics and analyze the nature of the converged networks.

Strength surpasses relatedness-queen larva selection in honeybees

Nepotism was initially theoretically predicted and sometimes found to trigger the selection of specific larvae to be reared as queens in the honeybee Apis mellifera. Although the importance of selecting the next queen for a colony indicates that it should not occur at random, nepotism is increasingly considered unlikely in eusocial insect societies. Different prenatal maternal supplies of embryos have been found to impact fitness in many other species and therefore could be a possible trigger underlying the likelihood of being raised as a queen. We offered related or unrelated larvae from six colonies originating from eggs of different weights for emergency queen rearing in queenless units with worker bees from these six colonies. We showed that nurses did not significantly prefer related larvae during queen rearing, which confirms the theory that different relatedness-driven kin preferences within a colony cannot be converted into a colony-level decision. However, we found that larvae originating from heavier eggs were significantly preferred for queen breeding. Studies on other species have shown that superior maternal supply is important for later reproductive success. However, we did observe tendencies in the expected direction (e.g., queens that hatched from heavier eggs had both more ovarioles and a shorter preoviposition period). Nevertheless, our data do not allow for a significant conclusion that the selection of larvae from heavy eggs truly offers fitness advantages.

How norm violators rise and fall in the eyes of others: The role of sanctions

Norm violators demonstrate that they can behave as they wish, which makes them appear powerful. Potentially, this is the beginning of a self-reinforcing loop, in which greater perceived power invites further norm violations. Here we investigate the possibility that sanctions can break this loop by reducing the power that observers attribute to norm violators. Despite an abundance of research on the effects of sanctions as deterrents for norm-violating behavior, little is known about how sanctions may change perceptions of individuals who do (or do not) violate norms. Replicating previous research, we found in two studies (N₁ = 203, N₂ = 132) that norm violators are perceived as having greater volitional capacity compared to norm abiders. Qualifying previous research, however, we demonstrate that perceptions of volition only translate into attributions of greater power in the absence of sanctions. We discuss implications for social hierarchies and point out avenues for further research on the social dynamics of power.

Social network dynamics predict hormone levels and behavior in a highly social cichlid fish

Group living confers many benefits while simultaneously exposing group members to intense competition. An individual's rise to prominence within a group may conflict with the overall functioning of the group. There is therefore a complex and dynamic relationship between the behavioral displays that directly benefit an individual, the consequences of these actions for the community, and how they feed back on individual-level fitness. We used a network analysis approach to study the link between behavior, social stability, and steroid hormone levels in replicate communities of the cichlid fish, Astatotilapia burtoni, which live in social groups with a dominance hierarchy. We demonstrate that individual behavior can have direct and indirect effects on the behavior of others while also affecting group characteristics. Our results show that A. burtoni males form stable social networks, where dominant individuals act as hubs for social interactions. However, there was variation in the temporal stability in these networks, and this variation in stability impacted hormone levels. Dominant males had higher testosterone levels, however, the differences in testosterone levels between dominant and subordinate males were greatest in stable communities. In sum, our analyses provide novel insights into the processes by which individual and community properties interact.

Does shelter influence the metabolic traits of a teleost fish?

Availability of shelter is an important component of habitat selection for animals as it can influence survival (protection against harsh physical conditions and predation) and growth (energy acquisition and expenditure). Few studies address the effect of shelter on metabolic expenditures associated with non-mechanical tasks (excluding station holding or movement). The main goal of this study was to investigate the influence of shelter use on metabolic traits of smallmouth bass (Micropterus dolomieu) from two populations (Kiamika River and Lake Long). Respirometry experiments on smallmouth bass were conducted to measure standard metabolic rate (SMR), resting metabolic rate (RMR), aerobic scope (AS), recovery time (RT) and excess post-exercise oxygen consumption (EPOC) in the presence or absence of shelter. The presence of shelter did not affect most metabolic traits, except for RMR, which was reduced in the presence of shelter for Lake Long fish. The results of this study also show that larger fish had lower SMR in the presence of shelter than when it was absent. When accounting for social hierarchy, there were no differences in most metabolic traits in dominant or subordinate fish in the presence or absence of shelter, except for RT, which was significantly lower in the presence of shelter for dominant fish. These results do not support the existence of an unequivocal relationship between individual metabolic traits and the presence of shelter. If physiological motives may influence the use of shelter, sheltering in itself might not have important consequences on energy expenditures required for non-mechanical tasks.

Identification of biogenic amines involved in photoperiod-dependent caste-fate determination during the adult stage in a temperate paper wasp

In the temperate paper wasp Polistes jokahamae, caste is influenced by photoperiod during the adult stage, but the mechanisms underlying the caste-fate determination system have been unclear. We measured the brain levels of monoamines and related substances in females kept isolated for two weeks under different photoperiods. Except for in the first-emerging group, the females developed ovaries under long-day conditions, whereas they stored lipids under short-day conditions. The levels of tyramine in the brain were significantly higher under long-day than under short-day conditions and positively correlated with maximum oocyte lengths. These results suggest that tyramine was produced in response to long daylength during the adult stage and associated with ovarian development, which is the principal characteristic of reproductive workers. There was also a significant positive correlation between dopamine levels in the brain and maximum oocyte length, independent of photoperiod, suggesting that dopamine is involved in reproductive function with tyramine resulting in the induction of reproductive workers. Meanwhile, higher levels of tryptophan in the brain were found in short-day conditions and positively correlated with lipid stores. However, serotonin synthesized from tryptophan and N-acetylserotonin were not associated with lipid stores without photoperiodic responses, suggesting that tryptophan is involved in the physiological changes toward gyne under short daylength, independently of serotonin signaling. In conclusion, tyramine and tryptophan are candidates for mediating photoperiod-dependent caste-fate determination in P. jokahamae: the former is involved in generating the worker caste while the latter is involved in generating the gyne caste.

Emergence of hierarchy in networked endorsement dynamics

Many social and biological systems are characterized by enduring hierarchies, including those organized around prestige in academia, dominance in animal groups, and desirability in online dating. Despite their ubiquity, the general mechanisms that explain the creation and endurance of such hierarchies are not well understood. We introduce a generative model for the dynamics of hierarchies using time-varying networks, in which new links are formed based on the preferences of nodes in the current network and old links are forgotten over time. The model produces a range of hierarchical structures, ranging from egalitarianism to bistable hierarchies, and we derive critical points that separate these regimes in the limit of long system memory. Importantly, our model supports statistical inference, allowing for a principled comparison of generative mechanisms using data. We apply the model to study hierarchical structures in empirical data on hiring patterns among mathematicians, dominance relations among parakeets, and friendships among members of a fraternity, observing several persistent patterns as well as interpretable differences in the generative mechanisms favored by each. Our work contributes to the growing literature on statistically grounded models of time-varying networks.

Who Sets the Aggressive Popularity Norm in Classrooms? It's the Number and Strength of Aggressive, Prosocial, and Bi-Strategic Adolescents

Previous work has shown that during adolescence, classrooms vary greatly in the extent to which aggression is rewarded with popularity (the ‘popularity norm’). Aggressive popularity norms may promote the proliferation of aggression and negatively affect the classroom climate. It is, however, unknown how these norms emerge in the first place. This longitudinal study therefore investigated whether aggressive popularity norms can be predicted by the classroom composition of students. We examined whether the prevalence of six student types - socially and non-socially dominant prosocial, aggressive, and bi-strategic adolescents (adolescents who are both highly prosocial and aggressive) - contributed to the norm by establishing a popularity hierarchy: strong classroom asymmetries in popularity. We collected peer-nominated data at three secondary schools in the Netherlands (SNARE-study; N_students = 2843; N_classrooms = 120; 51.4% girls; M_age = 13.2). Classroom-level regression analyses suggest that the classroom percentage of socially dominant aggressive and bi-strategic students predicted higher aggressive popularity norms, both directly and by enhancing the classrooms’ popularity hierarchy. Instead, the presence of non-socially dominant aggressive students and socially dominant prosocial students contributed to lower aggressive popularity norms. Socially dominant prosocial students also buffered against the role of socially dominant aggressive adolescents in the aggressive popularity norm (moderation), but not against bi-strategic adolescents’ role. Our findings indicate that interventions aimed at reducing aggressive popularity norms should first and foremost take the composition of classrooms at the start of the school year into account; and should not only encourage prosocial behavior, but also actively discourage aggression.

Infants' representation of social hierarchies in absence of physical dominance

Social hierarchies are ubiquitous in all human relations since birth, but little is known about how they emerge during infancy. Previous studies have shown that infants can represent hierarchical relationships when they arise from the physical superiority of one agent over the other, but humans have the capacity to allocate social status in others through cues that not necessary entail agents’ physical formidability. Here we investigate infants’ capacity to recognize the social status of different agents when there are no observable cues of physical dominance. Our results evidence that a first presentation of the agents' social power when obtaining resources is enough to allow infants predict the outputs of their future. Nevertheless, this capacity arises later (at 18 month-olds but not at 15 month-olds) than showed in previous studies, probably due the increased complexity of the inferences needed to make the predictions.

Effect of relative social rank within a social hierarchy on neural activation in response to familiar or unfamiliar social signals

Competent social functioning of group-living species relies on the ability of individuals to detect and utilize conspecific social cues to guide behavior. Previous studies have identified numerous brain regions involved in processing these external cues, collectively referred to as the Social Decision-Making Network. However, how the brain encodes social information with respect to an individual's social status has not been thoroughly examined. In mice, cues about an individual's identity, including social status, are conveyed through urinary proteins. In this study, we assessed the neural cFos immunoreactivity in dominant and subordinate male mice exposed to familiar and unfamiliar dominant and subordinate male urine. The posteroventral medial amygdala was the only brain region that responded exclusively to dominant compared to subordinate male urine. In all other brain regions, including the VMH, PMv, and vlPAG, activity is modulated by a combination of odor familiarity and the social status of both the urine donor and the subject receiving the cue. We show that dominant subjects exhibit robust differential activity across different types of cues compared to subordinate subjects, suggesting that individuals perceive social cues differently depending on social experience. These data inform further investigation of neurobiological mechanisms underlying social-status related brain differences and behavior.

Microaggressions and Psychological Health Among College Students: A Moderated Mediation Model of Rumination and Social Structure Beliefs

Racial microaggressions are common experiences for students of color on college campuses. Given prior research connecting microaggressions to negative mental health outcomes, it is important to better understand the social context and process through which microaggressions are associated with poorer mental health. In addition, we put forth a psycho-sociological approach to microaggressions, integrating an attention to both individual psychology and broader social structure. Specifically, the present study investigated whether the indirect association of school/workplace microaggressions and internalizing symptoms (i.e., depression, anxiety, and stress) through problem-focused thoughts (a subset of ruminative thinking) differed as a function of horizontal and vertical dimensions of individualism and collectivism among a racially diverse sample of non-White college students (n = 549) from two universities in the USA. As hypothesized, problem-focused thoughts mediated the associations between school/workplace microaggressions and all three negative mental health symptoms. Furthermore, the indirect effect of school/workplace microaggressions on psychological health through problem-focused thoughts was stronger in students with high levels of vertical individualism (i.e., autonomous but recognize/accept inequality among individuals), compared to students with low or average levels. Our findings suggest that students of color who endorse vertical individualism are at a relatively greater risk of negative mental health outcomes related to school/workplace microaggressions via problem-focused thoughts. Future research is needed to examine additional factors that may buffer or strengthen the pathways between microaggressions and negative mental health in students of color.