The development of collective personality: the ontogenetic drivers of behavioral variation across groups

Abstract

For the past decade, the study of personality has become a topic on the frontier of behavioral ecology. However, most studies have focused on exploring inter-individual behavioral variation in solitary animals, and few account for the role that social interactions may have on the development of an individual's personality. Moreover, a social group may exhibit collective personality: an emergent behavioral phenotype displayed at the group-level, which is not necessarily the sum or average of individual personalities within that group. The social environment, in many cases, can determine group success, which then influences the relative success of all the individuals in that group. In addition, group-level personality may itself evolve, subject to the same selection pressures as individual-level behavioral variation, when the group is a unit under selection. Therefore, we reason that understanding how collective personalities emerge and change over time will be imperative to understanding individual-and group-level behavioral evolution. Personality is considered to be fixed over an individual's lifetime. However, behavior may shift throughout development, particularly during adolescence. Therefore, juvenile behavior should not be compared with adult behavior when assessing personality. Similarly, as conditions within a group and/or the local environment can shift, group behavior may similarly fluctuate as it matures. We discuss potential within-group factors, such as group initiation, group maturation, genetic make-up of the group, and the internal social environment, and external factors, such as how local environment may play a role in generating group-level personalities. There are a variety of studies that explore group development or quantify group personality, but few that integrate both processes. Therefore, we conclude our review by discussing potential ways to evaluate development of collective personality, and propose several focal areas for future research.

The Effect of Keystone Individuals on Collective Outcomes Can Be Mediated through Interactions or Behavioral Persistence

“…Other rules, such as spontaneous increases in boldness, variation in persistence among group members, and interactions that lead to a decrease in boldness, will likely generate similar results as long as they follow an overall sink-source pattern. Furthermore, other mechanisms can also result in stable skewed behavioral distributions—for example, consistent variability in gene expression (Whitfield et al 2003; Ingram et al 2005), events during development (Bengston and Jandt 2014), and variation in morphology (Oster and Wilson 1978; Wilson 1980). Our simulation shows that a simple behavioral phenomenon, persistence, can produce highly skewed and stable behavioral distributions in a society when just one individual is highly influential.…”

“…For example, interaction patterns are potentially flexible because they can be determined by walking patterns (Pinter-Wollman et al 2014; Pinter-Wollman 2015), yet behavioral persistence can be rigid because it can be governed by gene expression (Whitfield et al 2003; Ingram et al 2005) and events during development (Bengston and Jandt 2014; Laskowski and Pruitt 2014). Therefore, we predict that dynamic environments will favor groups that can modify their behavioral composition through changes to interaction patterns, as in the high persistence–low acquisition scenario in our model.…”

Adult presence augments juvenile collective foraging in social spiders

“…Juvenile groups might behave more erratically than mature groups and/or lack the idiosyncratic intergroup differences in foraging behaviour that mature groups exhibit. Although the development of animal personality on the individual level has received increased attention during the last few years (Laskowski & Pruitt, 2014;Modlmeier, Laskowski, et al, 2014;Stamps & Groothuis, 2010), studies on the development of collective personality throughout a group's lifetime are virtually nonexistent (Bengston & Jandt, 2014; but see Gordon, 1991;McDonald & Topoff, 1986). All groups exhibited decreased prey capture participation with repeated observations.…”

Exposure to predators reduces collective foraging aggressiveness and eliminates its relationship with colony personality composition

“…Most studies on predator-prey interactions are performed on species of solitary or gregarious animals (Castellanos and Barbosa 2006; Bell and Sih 2007; Clinchy et al 2013; Cote et al 2013; David et al 2014). However, personality studies investigating social taxa have revealed the presence of stable differences in behavior at both the individual and group level (Jandt et al 2013; Bengston and Jandt 2014; Wright et al 2016b). The extent to which behavioral variation at either or both of these levels influences predator-prey interactions, or any other kind of species interaction for that matter, has been little explored.…”