Social Feedback and the Emergence of Rank in Animal Society

Abstract

Dominance hierarchies are group-level properties that emerge from the aggression of individuals. Although individuals can gain critical benefits from their position in a hierarchy, we do not understand how real-world hierarchies form. Nor do we understand what signals and decision-rules individuals use to construct and maintain hierarchies in the absence of simple cues such as size or spatial location. A study of conflict in two groups of captive monk parakeets (Myiopsitta monachus) found that a transition to large-scale order in aggression occurred in newly-formed groups after one week, with individuals thereafter preferring to direct aggression more frequently against those nearby in rank. We consider two cognitive mechanisms underlying the emergence of this order: inference based on overall levels of aggression, or on subsets of the aggression network. Both mechanisms were predictive of individual decisions to aggress, but observed patterns were better explained by rank inference through subsets of the aggression network. Based on these results, we present a new theory, of a feedback loop between knowledge of rank and consequent behavior. This loop explains the transition to strategic aggression and the formation and persistence of dominance hierarchies in groups capable of both social memory and inference.

How do lizards determine dominance? Applying ranking algorithms to animal social behaviour

“…For example, it is generally assumed that territorial animals only know their social rank in relation to their neighbours, as they do not have direct information on the relative fighting ability of individuals they have not yet encountered (Stamps, 1994). Yet, when natural hierarchies form, it is rare that interactions occur between all pairs of individuals; animals may instead infer their position in an overall hierarchy using feedback from interactions within a subset of the population (Hobson & DeDeo, 2015). Whether a population is structured by absolute or relative dominance, individual animals generally rely on the use of display and/or fighting behaviours to establish social status, and they require pairwise comparisons to determine their relative ranks.…”

La cotorra argentina (Myiopsitta monachus) en el Colegio de Postgraduados: ¿una especie invasiva?

“…Se han reportado conductas agresivas en cotorra argentina tanto inter como intraespecíficas (MacGregorFors et al 2011, Hobson y DeDeo 2015, aunque en este estudio sólo las segundas fueron observadas. En el caso de interacción con otras especies de aves, tanto Freeland (1973) como Wagner (2012) describieron agresiones con gorriones caseros en disputas por sitios de anidamiento.…”

“…Por otra parte, las conductas agresivas entre individuos de M. mo nachus fueron recurrentes en nuestras observaciones. Este comportamiento usualmente conlleva a establecer una dominancia jerárquica, además de cumplir con funciones de aprendizaje y socialización de la colonia (Camerino y Nos 1983, Hobson y DeDeo 2015.…”

Major Transitions in Political Order

“…Depth measures, by contrast, also make reference to higher-order facts such as the beliefs others hold about those who hold opinions about X. At least some work has confirmed the greater predictive power of depth measures [30], providing additional evidence that social facts are not simply compressions of individual-level beliefs, but complex, non-decomposable compressions where every n(n − 1) dyadic interaction influences each power score. 7 coarse-graining here is over time, summarizing the outcomes of multiple conflicts with a single binary variable.…”

“…High-resolution data on this knowledge-behavior loop [30] provides a dynamical picture of how individuals come to know the implicit hierarchies of their world, and alter their behavior in response. In contrast to the pigtail macaques of the example above, monk parakeets appear, so far, to lack a separate signaling system.…”