Quantifying uncertainty due to fission-fusion dynamics as a component of social complexity.

Groups of animals (including humans) may show flexible grouping patterns, in which temporary aggregations or subgroups come together and split, changing composition over short temporal scales, (i.e. fission and fusion). A high degree of fission-fusion dynamics may constrain the regulation of social relationships, introducing uncertainty in interactions between group members. Here we use Shannon's entropy to quantify the predictability of subgroup composition for three species known to differ in the way their subgroups come together and split over time: spider monkeys (Ateles geoffroyi), chimpanzees (Pan troglodytes) and geladas (Theropithecus gelada). We formulate a random expectation of entropy that considers subgroup size variation and sample size, against which the observed entropy in subgroup composition can be compared. Using the theory of set partitioning, we also develop a method to estimate the number of subgroups that the group is likely to be divided into, based on the composition and size of single focal subgroups. Our results indicate that Shannon's entropy and the estimated number of subgroups present at a given time provide quantitative metrics of uncertainty in the social environment (within which social relationships must be regulated) for groups with different degrees of fission-fusion dynamics. These metrics also represent an indirect quantification of the cognitive challenges posed by socially dynamic environments. Overall, our novel methodological approach provides new insight for understanding the evolution of social complexity and the mechanisms to cope with the uncertainty that results from fission-fusion dynamics.

Durability and flexibility of chimpanzee grooming patterns during a period of dominance instability.

Growing evidence from studies on primates and other taxa has shown that the maintenance of long-term affiliative patterns influences fitness. Thus, understanding how individuals regulate social interactions in response to environmental and social factors contributes to our understanding of the evolutionary basis of sociality. We investigated the durability of affiliation patterns in chimpanzees across three 3-month periods of varying social uncertainty depending on the degree of stability in the male hierarchy, with a 2-year gap between each period. Periods were unstable (no clear alpha male), recently stable (new alpha male just established) and stable (alpha male in place for 2 years). We focused on three features of social exchange shared by human and non-human primates: consistency of exchanges across periods, durability of preferred partners, and degree of reciprocity in each period. We compared male-to-male, female-to-female, male-to-female, and female-to-male grooming patterns. Overall, more grooming was exchanged in the stable period. Grooming patterns were not consistent across the three periods, but were only consistent between the recently stable and stable periods for female-to-female and male-to-female dyads. As predicted from the opportunistic nature of male relationships, male-to-male grooming was least likely to be correlated across all periods and males had relatively fewer durable (i.e., preferred partners in all periods) same-sex partners than females. Our predictions that grooming reciprocity would be less likely during the unstable period and in male-male dyads were only partially supported. We found grooming reciprocity in all periods for female-female dyads but only in the stable period for male-male and female-male dyads. Although long-term affiliative patterns are well studied in primates, this is the first study to investigate the association between social uncertainty and durability of affiliative patterns. Our findings suggest social uncertainty influences social exchange and highlight the importance of considering group instability in studies of social relationships.

Social uncertainty in the digital world.

The social world is inherently uncertain. We present a computational framework for thinking about how increasingly popular online environments modulate the social uncertainty we experience, depending on the type of social inferences we make. This framework draws on Bayesian inference, which involves combining multiple informational sources to update our beliefs.

Ostracism and suggestibility: how temporary cognitive deficits drive suggestibility after ostracism.

Interrogative suggestibility has been suggested to grow in situations of isolation. The current study aimed to test this assumption for the first time in an experimental approach. We hypothesized that ostracism increases suggestibility, and assumed this relationship to be mediated by cognitive impairments or social uncertainty. To test these hypotheses, we conducted two studies. We manipulated the state of ostracism (vs. inclusion) using the O-Cam (Study 1) and Cyberball paradigm (Study 2), and measured suggestibility using the Gudjonsson Suggestibility Scale. Results revealed an indirect link between inclusionary status and suggestibility. More precisely, there was no direct relationship between ostracism and suggestibility. However, ostracism induced weaker cognitive performances and this translated to increased suggestibility. Social uncertainty, on the other hand, did not serve as effective mediator. These findings indicate that each situation that is accompanied by (temporary) cognitive impairments, as is ostracism, might have the power to raise interrogative suggestibility.

Flexible use of contact calls in a species with high fission-fusion dynamics.

The 'social complexity hypothesis' posits that complex social systems (which entail high uncertainty) require complex communicative systems (with high vocal flexibility). In species with fission-fusion dynamics, where the fluid composition of temporary subgroups increases the uncertainty with which group members must manage their social relationships, vocal communication must be particularly flexible. This study assessed whether contact call rates vary with caller and audience characteristics in free-living spider monkeys, as well as with fission and fusion events. Adult females and immature individuals called more when in small audience settings, while audience size did not influence adult males. Adults called more when in the presence of the opposite sex, whereas immatures vocalized more in subgroups composed only by females. Females also called more when with their mature sons. We found higher call rates in periods during which fission and fusion events took place than in periods with more stable compositions and when the composition after a fission or fusion event changed from one sex to two sexes. A flexible use of contact calls allows individuals to identify themselves when they join others, particularly if they are members of the opposite sex. This socio-spatial cohesion function reduces the uncertainty about subgroup composition. This article is part of the theme issue 'Cognition, communication and social bonds in primates'.

Work stress, mental health, and employee performance.

The COVID-19 pandemic outbreak-as a typical emergency event-significantly has impacted employees' psychological status and thus has negatively affected their performance. Hence, along with focusing on the mechanisms and solutions to alleviate the impact of work stress on employee performance, we also examine the relationship between work stress, mental health, and employee performance. Furthermore, we analyzed the moderating role of servant leadership in the relationship between work stress and mental health, but the result was not significant. The results contribute to providing practical guidance for enterprises to improve employee performance in the context of major emergencies.