Collective decision‐making and fission–fusion dynamics: a conceptual framework

Abstract

Sociality exists in an extraordinary range of ecological settings. For individuals to accrue the benefi ts associated with social interactions, they are required to maintain a degree of spatial and temporal coordination in their activities, and make collective decisions. Such coordination and decision-making has been the focus of much recent research. However, eff orts largely have been directed toward understanding patterns of collective behaviour in relatively stable and cohesive groups. Less well understood is how fi ssion -fusion dynamics mediate the process and outcome of collective decisions making. Here, we aim to apply established concepts and knowledge to highlight the implications of fi ssion -fusion dynamics for collective decisions, presenting a conceptual framework based on the outcome of a small-group discussion INCORE meeting (funded by the European Community ' s Sixth Framework Programme). First, we discuss how the degree of uncertainty in the environment shapes social fl exibility and therefore the types of decisions individuals make in diff erent social settings. Second, we propose that the quality of social relationships and the energetic needs of each individual infl uence fi ssion decisions. Th ird, we explore how these factors aff ect the probability of individuals to fuse. Fourth, we discuss how group size and fi ssionfusion dynamics may aff ect communication processes between individuals at a local or global scale to reach a consensus or to fi ssion. Finally, we off er a number of suggestions for future research, capturing emerging ideas and concepts on the interaction between collective decisions and fi ssion -fusion dynamics.

Models in animal collective decision-making: information uncertainty and conflicting preferences

“…resting and foraging) in order to maintain group cohesion. However, the optimal timing of group activities can differ widely between individuals depending on their sex, age, size and physiological state, and suboptimal timing can involve costs to individuals [27,29,30,32,33,36,37,[55][56][57][58]. Therefore, there are often conflicts of interest about the timing of group activities.…”

Private information alone can trigger trapping of ant colonies in local feeding optima

“…The group decision comprises both the individual and collective decision-making mechanisms, and groups are not confined to making consensus decisions; rather, each individual can make their own personal decision. This may allow a group to utilise resources more efficiently in situations where a consensus is not required (Czaczkes et al, 2015a;Schürch and Grüter, 2014;Sueur et al, 2011). The utilisation of social information together with other information sources seems to be the rule, not the exception, for both individuals and groups (Beauchamp et al, 1997;Czaczkes et al, 2015b;Rieucau and Giraldeau, 2011;Templeton and Giraldeau, 1996).…”

Composite collective decision-making

“…R. Soc. B 282: 20142723 cohesion, group fission can occur [55]. Moreover, in socially foraging animals that share information, exploiting multiple food sources can keep the group informed of other options in the environment [56,57].…”

“…The ability to use resources more optimally by taking advantage of individual flexibility may be valuable not only for social insects. Group-living animals may respond to a dispersed distribution of food sources by group fission, and groups may fuse back together when large, clumped resources are available for exploitation [55]. Further afield, networking algorithms based on ant colony foraging (e.g.…”