Primate mosaic brain evolution reflects selection on sensory and cognitive specialization

DeCasien, Alex R.; Higham, James P.

doi:10.1038/s41559-019-0969-0

Cited by 76 publications

(102 citation statements)

References 99 publications

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“…However, one of the datasets contains brain region measurements that differ significantly from the others [25]. For this reason, we replicated our analyses using data from only the most carefully collected dataset [18]. These results are presented in the electronic supplementary material, appendix S1 (electronic supplementary material, tables S2 and S3).…”

Section: Methodsmentioning

confidence: 97%

‘Dunbar's number’ deconstructed

2021

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A widespread and popular belief posits that humans possess a cognitive capacity that is limited to keeping track of and maintaining stable relationships with approximately 150 people. This influential number, ‘Dunbar's number’, originates from an extrapolation of a regression line describing the relationship between relative neocortex size and group size in primates. Here, we test if there is statistical support for this idea. Our analyses on complementary datasets using different methods yield wildly different numbers. Bayesian and generalized least-squares phylogenetic methods generate approximations of average group sizes between 69–109 and 16–42, respectively. However, enormous 95% confidence intervals (4–520 and 2–336, respectively) imply that specifying any one number is futile. A cognitive limit on human group size cannot be derived in this manner.

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Section: Methodsmentioning

confidence: 97%

‘Dunbar's number’ deconstructed

2021

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“…For instance, the neocortex makes up the majority of the telencephalon in primates (Briscoe & Ragsdale, 2019). Group social complexity, diet and cognitive performance are positively associated with neocortex size in this taxon (Shultz & Dunbar, 2010; Reader, Hager & Laland, 2011; DeCasien & Higham, 2019). In birds, larger telencephalon size is associated with cognitive capacity in the form of feeding innovation (Timmermans et al, 2000).…”

Section: Introductionmentioning

confidence: 96%

Artificial mosaic brain evolution of relative telencephalon size improves cognitive performance in the guppy (Poecilia reticulata)

Triki

Fong

Amcoff

et al. 2021

Preprint

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The telencephalon is a brain region believed to have played an essential role during cognitive evolution in vertebrates. However, till now, all the evidence on the evolutionary association between telencephalon size and cognition stem from comparative studies. To experimentally investigate the potential evolutionary association between cognitive abilities and telencephalon size, we used male guppies artificially selected for large and small telencephalon relative to the rest of the brain. In a detour task, we tested a functionally important aspect of executive cognitive ability; inhibitory control abilities. We found that males with larger telencephalon outperformed males with smaller telencephalon. They showed faster improvement in performance during detour training and were more successful in reaching the food reward without touching the transparent barrier. Together, our findings provide the first experimental evidence showing that evolutionary enlargements of relative telencephalon size confer cognitive benefits, supporting an important role for mosaic brain evolution during cognitive evolution.

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“…Consistent with relative brain volume, neocortex and cerebellum volume relative to rest-of-brain volume (hereafter ‘relative neocortex and cerebellum volume’) was estimated by taking the residuals from a log-log regression of the combined neocortex and cerebellum volumes on the rest-of-brain volumes (i.e. total brain volume minus neocortex and cerebellum volumes) taken from Navarrete et al (2018) and the compilation in DeCasien & Higham (2019). Genus-level estimates for structural proxies of flexibility were calculated by taking the mean of the lineage estimates within each genus.…”

Section: Methodsmentioning

confidence: 99%

The role of behavioural flexibility in primate diversification

Creighton

Greenberg

Reader

et al. 2020

Preprint

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Understanding impacts on species diversification is fundamental to our understanding of the evolutionary processes underlying biodiversity. The 'behavioural drive hypothesis' posits that behavioural innovation, coupled with the social transmission of innovative behaviours, can increase rates of evolution and diversification, as novel behaviours expose individuals to new selection regimes. We test this hypothesis within the primates, a taxonomic group with considerable among-lineage variation in both species diversity and behavioural flexibility. We employ a time cut-off in our phylogeny to help account for biases associated with recent taxonomic reclassifications and compare three alternative measures of diversification rate that consider different phylogenetic depths. We find that the presence of behavioural innovation and social learning are positively correlated with diversification rates among primate genera, but not at shallower taxonomic depths. Given that we find stronger associations when examining older as opposed to newer diversification events even after controlling for potential sampling biases, we suggest that extinction resistance may be an important mechanism linking behavioural flexibility and diversification in primates. If true, our findings offer support for an expanded view of the behavioural drive hypothesis, and key predictions of this hypothesis can be tested as primates are forced to respond to ongoing environmental change.

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Primate mosaic brain evolution reflects selection on sensory and cognitive specialization

Cited by 76 publications

References 99 publications

‘Dunbar's number’ deconstructed

‘Dunbar's number’ deconstructed

Artificial mosaic brain evolution of relative telencephalon size improves cognitive performance in the guppy (Poecilia reticulata)

The role of behavioural flexibility in primate diversification

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