Potential Leaders Trade Off Goal-Oriented and Socially Oriented Behavior in Mobile Animal Groups

Abstract

Online enhancement: appendix. Dryad data: http://dx.doi.org/10.5061/dryad.qj07b.abstract: Leadership is widespread across the animal kingdom. In self-organizing groups, such as fish schools, theoretical models predict that effective leaders need to balance goal-oriented motion, such as toward a known resource, with their tendency to be social. Increasing goal orientation is predicted to increase decision speed and accuracy, but it is also predicted to increase the risk of the group splitting. To test these key predictions, we trained fish (golden shiners, Notemigonus crysoleucas) to associate a spatial target with a food reward ("informed" individuals) before testing each singly with a group of eight untrained fish who were uninformed ("naive") about the target. Informed fish that exhibited faster and straighter paths (indicative of greater goal orientation) were more likely to reach their preferred target and did so more quickly. However, such behavior was associated with a tendency to leave untrained fish behind and, therefore, with failure to transmit their preference to others. Either all or none of the untrained fish stayed with the trained fish in the majority of trials. Using a simple model of self-organized coordination and leadership in groups, we recreate these features of leadership observed experimentally, including the apparent consensus behavior among naive individuals. Effective leadership thus requires informed individuals to appropriately balance goal-oriented and socially oriented behavior.

Using a robotic fish to investigate individual differences in social responsiveness in the guppy

“…[13–16]). Thus, experimenters tried to control for or standardize the potential mutual interactions among subjects, either through training of stimuli subjects [17,18], experimental restriction of interaction possibilities [14,19,20], or by the use of video playbacks [21] or computer animations ([22,23], including virtual realities [24]). Here, we used another technological advancement that might provide a useful tool: biomimetic robots that mimic the appearance and behaviour of live animals and could thus be integrated into groups of live animals [25,26].…”

Who directs group movement? Leader effort versus follower preference in stickleback fish of different personality

“…Notably, bold individuals are more likely to lead, and shy individuals to follow [2][3][4]. At first glance, this might suggest that bolder individuals are more willing to initiate movement [5][6][7]. However, it is unclear to what extent leadership reflects the choices of leaders versus those of followers.…”

Social dynamics, network structure, and information diffusion in fish shoals.

“…For example, knowledgeable individuals can transmit information to naïve group members by acting as leaders during collective movements (Swaney et al, 2001;Webster et al, 2013;Ioannou et al, 2015) or by otherwise directing attention towards relevant environmental stimuli-e.g., postural changes or foraging pecks can indicate the presence of food (Lachlan et al, 1998). In addition, olfactory cues associated with foraging may provide a tip-off to uninformed individuals regarding the presence of prey items (Morrell et al, 2007;Johannesen et al, 2012).…”

“…Social transmission of foraging information in fish shoals can occur through relatively simple social learning mechanisms, such as local enhancement (Thorpe, 1956;. For instance, knowledgeable individuals can lead naïve group mates to a foraging site during collective movements (Swaney et al, 2001;Ioannou et al, 2015), while visual and olfactory cues associated with foraging can provide tip-offs to uninformed individuals (Lachlan et al, 1998;Johannesen et al, 2012). In the low-risk groups, social transmission appeared to operate independently of the association networks, which is consistent with individuals in these groups tending to approach and interact with the device as part of a large, cohesive shoal.…”

“…Ten seconds is more than sufficient time for a guppy to travel the length of the arena. Furthermore, social transmission can occur over shorter timescales (Strandburg-Peshkin et al, 2013;Ioannou et al, 2015), meaning the estimates of its effects in this study are potentially conservative. The bold-leader networks tested whether bold individuals were more effective demonstrators-e.g., if informed bold individuals were especially likely to lead other group members to the food source (Aplin et al, 2014;McDonald et al, 2016).…”