Abstract
The prevailing hypotheses for the evolution of cognition focus on either the demands associated with group living (the social intelligence hypothesis (SIH)) or ecological challenges such as finding food. Comparative studies testing these hypotheses have generated highly conflicting results; consequently, our understanding of the drivers of cognitive evolution remains limited. To understand how selection shapes cognition, research must incorporate an intraspecific approach, focusing on the causes and consequences of individual variation in cognition. Here, we review the findings of recent intraspecific cognitive research to investigate the predictions of the SIH. Extensive evidence from our own research on Australian magpies (Cracticus tibicen dorsalis), and a number of other taxa, suggests that individuals in larger social groups exhibit elevated cognitive performance and, in some cases, elevated reproductive fitness. Not only do these findings demonstrate how the social environment has the potential to shape cognitive evolution, but crucially, they demonstrate the importance of considering both genetic and developmental factors when attempting to explain the causes of cognitive variation.This article is part of the theme issue ‘Causes and consequences of individual differences in cognitive abilities’.
Highlights
The prevailing hypotheses for the evolution of cognition focus on either the demands associated with group living (the social intelligence hypothesis (SIH)) or ecological challenges such as finding food
Recent studies focusing on individual variation in cognition have produced exciting results, indicating that an intraspecific approach to the study of cognitive evolution, may be a valuable addition to comparative studies as a means of furthering our understanding of cognitive evolution
We found individual performance was significantly positively correlated across all four tasks, and a principal component analysis (PCA) revealed evidence of a general cognitive factor underlying cognitive performance [67]
Summary
Scientists have investigated the factors governing cognitive evolution, yet the topic still remains intensely debated today. Unpredictable resource availability may favour more innovative individuals if novel foraging techniques allow the exploitation of a new food source In this vein, there is evidence of a positive relationship between innovativeness and brain size in both primates and birds (reviewed in [14]). The majority of evidence supporting the SIH is derived from comparative studies on primates and birds [31,32], relating between-species or between-population differences in brain size or cognitive performance to differences in social organization or life history [1,32,33,34,35,36]. Recent studies focusing on individual variation in cognition have produced exciting results (e.g. the role that cognition plays in mate choice [42]), indicating that an intraspecific approach to the study of cognitive evolution, may be a valuable addition to comparative studies as a means of furthering our understanding of cognitive evolution
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