The Influence of Social Hierarchy on Primate Health

“, SES) is speculative, the link between a particular rank status and deleterious health outcomes is clear for subordinates (presumably low SES; Adler et al., 2000; Sapolsky, 2005) and highest ranking dominants (presumably high SES, Gesquiere et al.”

“Similar to what Sapolsky (2005) reports for health effects in various primate hierarchies, we find that upward mobility in work situation quality is possible even under relatively low-control conditions.”

“Lower ranking, or more subordinate animals, are thereby exposed continuously to an adverse social environment, similar to that experienced by people [31].”

“…psychosocial stress exposure in females that is characterized by constitutive exposure to adverse social environment, similar to that experienced by people and implicated in the development of stress-induced disorders, is that of social subordination in socially housed female macaque monkeys [77].”

“…Pittet, Johnson, & Hinde, 2017), experience increased levels of social support and 168 affiliation (Snyder-Mackler et al., 2016), and have lowered risks of illness (Sapolsky, 2005) and 169 chronic stress (Qin et al., 2013; Sapolsky, 2005), all of which may collectively increase the 170 lifespan.”

“Importantly, the physiological consequences of both aging and social stress in nonhuman primates often parallel those observed in humans (Roth et al., 2004; Sapolsky, 2005), including at the level of gene expression (Somel et al., 2010; Tung & Gilad, 2013).”

“57 man). tology, Rabin Medical Cen (McEwen, 2000; Sapolsky, 2005).”

“…in that subordinate animals ‘‘may have to work harder for calories, or be calorically deprived’’ and be ‘‘the subjects of unprovoked displacement aggression’’ (Sapolsky, 2005, p. 397), among some species being at the top of a dominance hierarchy can also be quite stressful (because of aggressive…”

“his/her level of stress [1,2].”

“…structure when the given population is not homogeneous but consists of several groups or ranks is a phenomenon widely observed for many different species (Wilson, 1971; Lomnicki, 1988; Savolainen and Vepsalainen, 1988; Moehlman, 1989; Freeman et al., 1992; Vos et al., 2004; Sapolsky, 2005).”

“Somewhat different but similarly interesting is research showing that a host of biological functions among members of different troops of the same species of primates, such as chimpanzees and baboons, vary with the stressful aspects of their social organization and the enforcement of authority hierarchies ( Sapolsky,…”

“Furthermore, attributes such as body condition or health frequently correlate with rank (Sapolsky 2005; Giles et al. 2015), but these were not systematically collected in the present study.”

“…aggression by dominants, circulating concentrations of glucocorticoids (GC) are usually higher in subordinates than in dominants (Creel 2001; Abbott et al. 2003; Goymann and Wingfield 2004; Sapolsky 2005; Benhaiem et al. 2013) and may impair immune processes (Glaser and Kiecolt-Glaser 2005).”

“Social structure in non-human primates is largely dominated by hierarchy and affiliation 6 .”

“Studies conducted on non-human primates (McGuire et al., 1983; Raleigh et al., 1984; Sapolsky, 2005) suggest that serotonin levels vary as a function of primates’ social status.”

“In particular, psychological intimidation (such as eye contact in primates), as opposed to overt aggression, requires little energy from dominants, but can increase stress levels in subordinates (Sapolsky 2005).”

“In contrast, dominant individuals have generally lower levels of affiliative behaviour (humans: Guinote et al., 2015; non-human primates: Seyfarth & Cheney, 2003; Sapolsky, 2005).”

“As a physiological insult, social stressors produce salient responses along the animals’ lifespan [5], such that in primates, stress linked to the position an individual occupies within its hierarchy is the single best predictor of health [2].”

“Research on non-human primates suggests, however, that high power can be stressful as well, especially when one s power position is threatened (i.e. when the power hierarchy is unstable; Sapolsky, 1993, 2005; Sapolsky & Share, 1994).”

“Social rank has adverse adrenocortical, cardiovascular, reproductive, immunological, and neurobiological consequences that lead to differences in health outcomes across primate species (reviewed in Sapolsky 2005).”

“Thus, the conventional view of a negative link between both groups of hormones could be due to non-natural conditions, such as chronic individual stress (Sapolsky 2005) or laboratory/captivity studies where dominant and subordinate individuals are forced to interact (Creel 2001).”

“In contrast, low-ranking individuals generally experience social constraints, helplessness, and uncertainty [28].”

“…male elephants (Brown et al., 2007) and may be explained by the increased physiological cost associated with increased dominance in older animals ( Sapolsky, 2005; Gobush et al., 2008) [but see Barrette et al., 2012 and Levy et al., 2020] and/or normal aging processes (Sapolsky et al., 1986;…”

“Many people are incentivized to improve their place in the social hierarchy, defined as one’s influence on the allocation of resources and group decisions (Anderson et al., 2015; Brown, 1991; Cheng et al., 2013; Sapolsky, 2005; von Rueden et al., 2011).”

“…subordinate status is often considered the more “stressful” social status, comparative data suggest that in approximately half of the species surveyed, dominant individuals were more stressed (Creel, 2001), which can itself be associated with negative fitness consequences (e.g., Sapolsky, 2005).”

“…Tardif et al., 2004; Beehner et al., 2006; Lujan et al., 2006) and social (Colmenares & Gomendio, 1988; Bercovitch & Strum, 1993; Wasser et al., 1998; van Noordwijk & van Schaik, 1999; Sapolsky, 2005; Marashi & R€ulicke, 2012; Roberts et al., 2012) threats can induce the Bruce effect in animals.”

“In such cases, social status can greatly affect an individual’s behavior and physiology through interactions with its conspecifics (Sapolsky 2005).”

“(Sapolsky, 2005, p. 648).”

“However, our finding that assigned dominance rank was not correlated with any of the four indices of behavioural responsiveness adds to the evidence from non-human primates suggesting that coping strategies are not directly linked to social status (Sapolsky 2000, 2005).”

“Social subordination in macaques is associated with reduced control of the environment (50) and leads to a dysregulation of the LHPA axis (38, 41, 51, 64), as well as changes in behavior and physiology including reproductive dysfunction (44, 53), immune compromise (54–56), addictive behavior (57), and cardiovascular d…”

“Overall, however, a large body of evidence indicates that the benefits of social support far outweigh the costs (e.g., Uchino et al., 1996), as do the benefits of status for humans (e.g., Sapolsky, 2005).”

“It may affect many aspects of its life, such as access to food (Baker et al. 1981), health and physiology (Sapolsky 2005) or reproductive success (Ellis 1995; Creel et al. 1997), therefore entailing serious fitness consequences.”

“Conversely, these benefits may be offset by the increased risks for such individuals, for example from metabolic costs of dominance [37,38], or risks they pose to others, such as their increased propensity to transmit infectious agents [7,8,33] or disrupt reproduction through hyper-aggressiveness [39].”

“Research has shown that both dominants and subordinates, may experience physiological costs related to their social status (Creel 2001; Sapolsky 2005).”

“Dominant males face greater cognitive demands than subordinate males because they need to be more attentive and responsive to changes in the social landscape while maintaining their position in the hierarchy (Sapolsky, 2005).”

“18 This review highlights the organizing properties of biobehavioral social systems as a set of mechanisms that have a common functional theme and act as a coordinated set of neural, hormonal, cognitive, and behavioral processes [31; 80; 81].”

“In primates, a model for social species, the loss of a dominant member may affect their group stability and influence individuals’ stress levels [29].”

“It is well known that social status can bring forth forms of resources and competition (Georgiev et al., 2015; Sapolsky, 2005) and can thus influence glucocorticoid levels (Cavigelli & Caruso, 2015; Gesquiere et al., 2011; Rosenbaum et al., 2020; Sapolsky, 2005; Zhang, Cui, et al., 2018).”

“The status system monitors the relative social standing of group members and uses this information to guide behavior (Mahadevan et al., 2016; Sapolsky, 2005).”

“Individual differences have been shown to moderate the relationships between patterns of CORT functioning and maladaptive outcomes (e.g., Gunnar, Kryzer, Van Ryzin, & Phillips, 2011; McEwen, 1998; Phillips, Fox, & Gunnar, 2011; Sapolsky, 2005; Shoal, Giancola, & Kirillova, 2003).”

“Social rank can even impact the health of individuals (Sapolsky, 2005).”

“…details on 100% of winning candidates and over 96% of losing candidates in US history who fall within the appropriate RD bandwidth.6 The combined sample is over 100 times larger than that of presidents, with over 3Evidence on this theory largely comes from animal studies (Sapolsky, 2005).”

“However, primates at the top of colonies for which there is threats and competition for dominance follow the opposite pattern (Sapolsky, 2005).”

“However, this instability will likely resolve at some point (though no research to our knowledge has specifically examined the half-life of hierarchy instability), whereas the stable low-status position, by definition, may represent a longer-term threat akin to a chronic stressor [49].”

“Social status has also been linked to increased wellbeing, better health, and lower morbidity rates (Adler, Epel, Castellazzo & Ickovics, 2000; Boyce, 2004; Sapolsky, 2004, 2005).”

“Consistent with prior studies (Louch and Higginbotham, 1967; Schuhr, 1987; Sapolsky, 1992, 2005, 2011; Sapolsky et al., 1997), corticosterone levels were observed in decreasing order as low-rank mice > high-rank mice > middlerank mice.”

“Sapolsky RM. 2005.”

“In the social scale, subordinate individuals experience social stress; however, experimental models have shown that, contrary to common belief, dominant individuals may also have significant indices of physiological stress.(38) Persons hyperreactive to novelty have higher stress hormones(39) and higher indices of athe…”

“In short, the extent in time and the form of dominance status depend on the social system of each species, as well as on environmental, physiological, and phenotypic factors (Sapolsky, 2005).”

“…and corticosterone are the major glucocorticoids secreted in response to the activation of the hypothalamic–pituitary–adrenal axis which, along with other mechanisms, modulates the physiological responses of individuals to environmental stressors (Sapolsky 2002, 2005; Stratakis and Chrousos 1995).”

“In line with the literature on social hierarchies (Sapolsky 2005), it may be that the working conditions of sole proprietors are more stressful than of the other occupational groups due to more financial insecurity, less control over work, and perhaps less work-family balance.”

“In chimpanzees, rank is maintained through frequent aggression from dominant animals, whereas in baboons, rank is maintained more through intimidation (i.e., displacements and threats; Muller & Wrangham, 2004; Sapolsky, 2005).”

“In many other species that form dominance hierarchies, such as baboons (Sapolsky, 2005), there are differences in CORT levels depending on the dominant or subordinate status of the individual.”

“It is not surprising that people are particularly attentive to the relative differences in the hierarchy between themselves and others as social hierarchy highly affects individuals’ social and physical welfare within the group (Sapolsky, 2005).”

“…dominance hierarchy generally have higher levels of circulating cortisol, lower levels of gonadal steroids, exhibit higher rates of anxious- and depressivelike behavior, and are more likely to be in poor health [Gesquiere et al., 2011; Onyango et al., 2008; Sapolsky, 2005; Shively et al., 2005].”

“Maintaining a high-status position within such a fluid social structure requires heightened vigilance towards potential threats, particularly those that might challenge an individual’s social standing [70].”

“It can be automatically and efficiently inferred, indicating the existence of biological systems that process social rank or social hierarchy’s information 23,24,25 .”