Front Individuals Lead in Shoals of Three-Spined Sticklebacks (Gasterosteus Aculeatus) and Juvenile Roach (Rutilus Rutilus)

Bumann, Dirk; Krause, Jens

doi:10.1163/156853993x00236

Cited by 86 publications

(86 citation statements)

References 9 publications

(7 reference statements)

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“…Previous experimental work suggests that group heading is determined by frontal group members passing information to the rear (43,44). In pigeons, particular individuals occupy these frontal positions and are consistently more likely to initiate changes in direction and to be followed by others (45).…”

Section: Discussionmentioning

confidence: 97%

Inferring the structure and dynamics of interactions in schooling fish

Katz

Tunstrøm

Ioannou

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

813

896

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Determining individual-level interactions that govern highly coordinated motion in animal groups or cellular aggregates has been a long-standing challenge, central to understanding the mechanisms and evolution of collective behavior. Numerous models have been proposed, many of which display realistic-looking dynamics, but nonetheless rely on untested assumptions about how individuals integrate information to guide movement. Here we infer behavioral rules directly from experimental data. We begin by analyzing trajectories of golden shiners (Notemigonus crysoleucas) swimming in two-fish and three-fish shoals to map the mean effective forces as a function of fish positions and velocities. Speeding and turning responses are dynamically modulated and clearly delineated. Speed regulation is a dominant component of how fish interact, and changes in speed are transmitted to those both behind and ahead. Alignment emerges from attraction and repulsion, and fish tend to copy directional changes made by those ahead. We find no evidence for explicit matching of body orientation. By comparing data from two-fish and three-fish shoals, we challenge the standard assumption, ubiquitous in physics-inspired models of collective behavior, that individual motion results from averaging responses to each neighbor considered separately; three-body interactions make a substantial contribution to fish dynamics. However, pairwise interactions qualitatively capture the correct spatial interaction structure in small groups, and this structure persists in larger groups of 10 and 30 fish. The interactions revealed here may help account for the rapid changes in speed and direction that enable real animal groups to stay cohesive and amplify important social information.A fundamental problem in a wide range of biological disciplines is understanding how functional complexity at a macroscopic scale (such as the functioning of a biological tissue) results from the actions and interactions among the individual components (such as the cells forming the tissue). Animal groups such as bird flocks, fish schools, and insect swarms frequently exhibit complex and coordinated collective behaviors and present unrivaled opportunities to link the behavior of individuals with dynamic group-level properties. With the advent of tracking technologies such as computer vision and global positioning systems, group behavior can be reduced to a set of trajectories in space and time. Consequently, in principle, it is possible to deduce the individual interaction rules starting from the observed kinematics. However, calculating interindividual interactions from trajectories means solving a fundamental inverse problem that appears universally in many-body systems. In general, such problems are very hard to solve and, even if they can be solved, their solution is often not unique.To avoid solving these inverse problems (and because detailed kinematic data were not available until recently), many attempts have been made to replicate the patterns observed in animal groups by...

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Section: Discussionmentioning

confidence: 97%

Inferring the structure and dynamics of interactions in schooling fish

Katz

Tunstrøm

Ioannou

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

813

896

View full text Add to dashboard Cite

show abstract

“…In animal groups, effective distributed decision making occurs across a range of taxa and environmental contexts (7,(9)(10)(11)(12)(13)(14)(15)(16)(17), making them an excellent model in which to study the evolved capabilities of collectives. Individuals in groups must balance personal information, accumulated from their own past experiences, with potentially conflicting social information, gleaned from the behavior of conspecifics.…”

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confidence: 99%

“…10-13). The two-choice paradigm has also been employed to investigate decisions made by groups of individuals (9,(14)(15)(16), but here the tendencies to maintain group cohesion and to maximize information acquisition will both indicate the same choice and these factors are therefore confounded in the resulting data. For example, copying the choice made by the majority of previous individuals both maximally reduces the risk of isolation and is the option most favored by social information.…”

mentioning

confidence: 99%

Both information and social cohesion determine collective decisions in animal groups

Miller

Garnier

Hartnett

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

141

136

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During consensus decision making, individuals in groups balance personal information (based on their own past experiences) with social information (based on the behavior of other individuals), allowing the group to reach a single collective choice. Previous studies of consensus decision making processes have focused on the informational aspects of behavioral choice, assuming that individuals make choices based solely on their likelihood of being beneficial (e.g., rewarded). However, decisions by both humans and nonhuman animals systematically violate such expectations. Furthermore, the typical experimental paradigm of assessing binary decisions, those between two mutually exclusive options, confounds two aspects common to most group decisions: minimizing uncertainty (through the use of personal and social information) and maintaining group cohesion (for example, to reduce predation risk). Here we experimentally disassociate cohesion-based decisions from information-based decisions using a three-choice paradigm and demonstrate that both factors are crucial to understanding the collective decision making of schooling fish. In addition, we demonstrate how multiple informational dimensions (here color and stripe orientation) are integrated within groups to achieve consensus, even though no individual is explicitly aware of, or has a unique preference for, the consensus option. Balancing of personal information and social cues by individuals in key frontal positions in the group is shown to be essential for such group-level capabilities. Our results demonstrate the importance of integrating informational with other social considerations when explaining the collective capabilities of group-living animals.collective intelligence | golden shiner | behaviour | Bayesian U nderstanding the mechanisms of social influence and collective intelligence is a key challenge in contemporary science (1-5) and is essential for achieving progress in a variety of fields ranging from the organization of gregarious and social organisms (6-8) to the dynamics of information exchange in human societies (1-4). In animal groups, effective distributed decision making occurs across a range of taxa and environmental contexts (7, 9-17), making them an excellent model in which to study the evolved capabilities of collectives. Individuals in groups must balance personal information, accumulated from their own past experiences, with potentially conflicting social information, gleaned from the behavior of conspecifics. Additionally, achieving a single consensus choice is often crucial to maintaining group cohesion, and individuals that make a dissenting choice may find themselves isolated, increasing their risk of predation (18). Thus, additional social considerations-such as attempting to minimize the risk of isolation-may bias individual decisions away from what might be predicted from purely informational considerations (19)(20)(21)(22). Both humans (23-25) and nonhuman animals (26-31) have been shown to make such biased decisions, which are not b...

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“…A leader traditionally is considered to be the animal in the front of a group movement (Kiflawi and Mazeroll 2006;Miller et al 1972). Although animals in the front position can direct group movements (Bumann and Krause 1993;Reebs 2000), positioning of leaders might be difficult to distinguish in slow foraging-bout movements (Dumont et al 2005) and in small groups where all members can communicate with each other by visual, olfactory, or auditory signals (Boinski 1993;King and Cowlishaw 2009).…”

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confidence: 99%

Leadership in mixed-sex groups of muskoxen during the snow-free season

Ihl

Bowyer

2011

J Mammal

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In social ungulates particular individuals or cohorts, such as adult females, can lead or initiate foraging movements. We use muskoxen (Ovibos moschatus) as a model system to test hypotheses regarding the sex and age class of leaders and the potential costs of leadership in 3 different behavioral contexts: activity initiation, foraging-bout movements, and spontaneous group movements. We conducted research on approximately 160 muskoxen at Cape Krusenstern National Monument adjacent to the coast of the Chuckchi Sea in northwestern Alaska. We observed free-ranging, mixed-sex groups of muskoxen from the ground during 5 June-22 September 2002. Adult females emerged as leaders in all 3 contexts, and other group members were more likely to follow adult females than adult males during initiations of activity. Half of successful initiations by adult males included aggressive behavior toward females. Males took a more active role during rut (the mating season) by provoking females to initiate group activity and by actively manipulating spontaneous movements led by females through herding and blocking activities. Leaders incurred no obvious costs in terms of lost foraging time. Costs and benefits of leadership can be subtle and difficult to measure in the field and can include foraging and reproductive trade-offs and increased risk of predation.

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Front Individuals Lead in Shoals of Three-Spined Sticklebacks (Gasterosteus Aculeatus) and Juvenile Roach (Rutilus Rutilus)

Cited by 86 publications

References 9 publications

Inferring the structure and dynamics of interactions in schooling fish

Inferring the structure and dynamics of interactions in schooling fish

Both information and social cohesion determine collective decisions in animal groups

Leadership in mixed-sex groups of muskoxen during the snow-free season

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