Behavioral and Brain Sciences最新文献

Ectotherms, particularly fish, challenge traditional brain evolution theories by exhibiting advanced cognitive abilities despite their smaller brains. While the social brain hypothesis may apply within clades, sensory-motor systems likely explain the brain size differences between average-brained ectotherms and endotherms. Evolved complex sensory-motor systems suggest that brain evolution models should expand to include sensory and motor systems, beyond cognitive processes alone.

Dunbar explains primates group cohesion through cognitive and structural mechanisms like grooming and social cognition. We extend this by highlighting collective social niche construction, where emergent social properties arise from feedback loops, selection pressures, and self-organisation. Adaptive social networks evolve through multilevel selection, cultural transmission, and ontogenetic changes, shaping survival, cognition, and collective intelligence across species.

Dunbar exclusively sees groups as arising through the aggregate relationships between individuals and thereby makes the serious omission of not considering the capacity of those individuals to categorize one another as ingroup versus outgroup members.

Specialised forms of social cognition enable primates to manage the stresses of group living by allowing for flexible and intentional communication. This is used to increase the predictability of conspecifics' behaviour for both signallers and receivers. Intentional communication helps to overcome the stimulus-driven processing that may occur due to stress, enhancing attention allocation in receivers.

Dunbar's emphasis on dyadic relationships in group formation overlooks the roles of interdependence and joint commitment in social cohesion. We challenge his premise by highlighting the importance of group-level processes, particularly where top-down group pressures like cooperative breeding and out-group threat can induce joint commitment as an alternate means to sustain group cohesion.

As the third solution to group dispersion, Dunbar proposes primates use several higher order cognitive skills to especially manage 'weak ties' in a nuanced and fast-tracked way, therewith avoiding unnecessary conflicts. We here argue that subconscious, automatic processes including attention allocation and behavioral or neurophysiological state matching can serve a similar function in maintaining group cohesion.

The Social Brain Hypothesis (SBH) connects primate brain size to social complexity but faces empirical limitations. We propose expanding the SBH by incorporating hippocampal functions across species, demonstrating how cognition emerges from both social and ecological pressures. This extended framework moves beyond cortical-centric models, providing a comprehensive understanding of brain evolution and the origins of human cognitive abilities, including language.

Grooming and cognition support primate group cohesion but are insufficient for maintaining stability in large groups. We propose tolerance, the capacity to accommodate social stress, as an additional mechanism. Tolerance fosters flexible social skills and cooperation beyond small cliques. Shaped by hormonal adaptation and development, tolerance plays a foundational role in overcoming group size limits by sustaining complex social networks.

Dunbar suggests structural, behavioral, and cognitive mechanisms to mitigate the costs of living in large groups. While we generally concur with the notion of group size effects on female productivity, we call for a more explicit treatment of how functional support alleviates social costs and disagree with the outright dismissal of ecological drivers and phylogenetic inertia.

Grooming is one strong mechanism allowing primate groups to grow larger and more cohesive, but a reduction in reactive aggression responses can be expected to have contributed to this trend too. There is indeed a partial overlap between the neurobiology of grooming and the neurobiology of reactive aggression.