Overall Brain Size, and Not Encephalization Quotient, Best Predicts Cognitive Ability across Non-Human Primates

@article{Deaner2007OverallBS,
  title={Overall Brain Size, and Not Encephalization Quotient, Best Predicts Cognitive Ability across Non-Human Primates},
  author={Robert O. Deaner and Karin Isler and Judith M Burkart and Carel P. van Schaik},
  journal={Brain, Behavior and Evolution},
  year={2007},
  volume={70},
  pages={115 - 124}
}
For over a century, various neuroanatomical measures have been employed as assays of cognitive ability in comparative studies. Nevertheless, it is still unclear whether these measures actually correspond to cognitive ability. A recent meta-analysis of cognitive performance of a broad set of primate species has made it possible to provide a quantitative estimate of general cognitive ability across primates. We find that this estimate is not strongly correlated with neuroanatomical measures that… 

Figures and Tables from this paper

Species differences in executive function correlate with hippocampus volume and neocortex ratio across nonhuman primates.
TLDR
It is shown that competence on a series of eight executive function cognitive tasks both correlate across tasks and with brain size and architecture across species, and that commonly used indices of encephalization, such as residuals of brain volume regressed on body size, may confound rather than clarify matters.
Encephalization, Neuronal Excess, and Neuronal Index in Rodents
TLDR
It is shown that more encephalized rodent species have the number of neurons expected for their brain size, but a larger number of cells than expected for the body size, and proposed that the total number of excess neurons in each species should be a better indicator of cognitive abilities than the encephalization quotient.
Numbers of neurons as biological correlates of cognitive capability
Are brain weights estimated from scaling relationships suitable for comparative studies of animal cognition?
TLDR
To test the link between performance in various cognitive tasks and variation in brain size, the authors relied on data for body weight, which was transformed into ‘estimated brain weight’ using the allometric scaling relationship between brain and body size, an approach that can be found in other papers which lack sufficient neuroanatomical data.
Beyond brain size
TLDR
It is suggested that a synergistic combination of the ‘bottom up’ approach of classical neuroethology and the 'top down' approach of comparative biology/psychology within closely related but behaviorally diverse clades can limit the effects of heterogeneity, interference, and noise.
Old World Monkeys Compare to Apes in the Primate Cognition Test Battery
TLDR
The results question the clear-cut relationship between cognitive performance and brain size and support the view of an accelerated evolution of social intelligence in humans.
Absolute brain size predicts dog breed differences in executive function
TLDR
The results suggest that evolutionary increases in brain size are positively associated with taxonomic differences in executive function, even in the absence of primate-like neuroanatomy, and suggest that variation between dog breeds may present a powerful model for investigating correlated changes in neuroAnatomy and cognition among closely related taxa.
Whole Brain Size and General Mental Ability: A Review
TLDR
The brain size/GMA correlations with age, socioeconomic position, sex, and ancestral population groups are described, which provide information about brain–behavior relationships and from an evolutionary and behavior genetic perspective.
Brain morphology correlates of learning and cognitive flexibility in a fish species (Poecilia reticulata)
TLDR
Rare evidence supporting the theory that more neural tissue in key brain regions confers cognitive benefits is found, including telencephalon size, which emerges as an important neural correlate of higher executive functions such as cognitive flexibility.
...
...

References

SHOWING 1-10 OF 91 REFERENCES
The primate neocortex in comparative perspective using magnetic resonance imaging.
In this study we use neuroanatomic data from living anthropoid primate subjects to test the following three hypotheses: (1) that the human neocortex is significantly larger than expected for a
Visual influences on primate encephalization.
  • E. Kirk
  • Biology
    Journal of human evolution
  • 2006
Intelligence and brain size in 100 postmortem brains: sex, lateralization and age factors.
TLDR
It was found that cerebral volume decreased only minimally with age in women, leaving the basis of the well-documented sex difference in cerebral volume unaccounted for, and point to the need for responsibility in the consideration of the possible use of brain images as intelligence tests.
Primate encephalization and intelligence.
TLDR
Results suggest that the most accurate means for quantifying the encephalization of humans and other adult primate species requires the use of Lapicque's universal exponent of 0.28 in Snell's equation of simple allometry.
Neocortex size predicts deception rate in primates
  • R. Byrne, N. Corp
  • Biology, Psychology
    Proceedings of the Royal Society of London. Series B: Biological Sciences
  • 2004
TLDR
It is shown that the use of deception within the primates is well predicted by the neocortical volume, when observer effort is controlled for; by contrast, neither the size of the rest of the brain nor the group size exert significant effects.
Relationships between factors of intelligence and brain volume
Evolutionary Anatomy of the Primate Cerebral Cortex: Bigger is better: primate brain size in relationship to cognition
TLDR
Considering considerations suggest that among closely related mammalian species those with the larger brains may well have the greatest mental abilities, not only will they have greater overall information processing capacities, but also, in many cases, they will have increased numbers of neural modules, increased size of the neocortex and of other higher neural processing areas, and increased neural connectivity.
Comparative Tests of Primate Cognition: Different Scaling Methods Produce Different Results
TLDR
Previous comparative studies are inconclusive and further research is needed to develop a scaling method where relative measures of brain structure size are demonstrated to correspond with behavioral performance, as well as allowing a distinction between social and ecological hypotheses.
Intelligence and brain structure in normal individuals.
TLDR
The results suggest that the size of some cerebral structures may account for a significant, but modest, proportion of the variance in human intelligence.
Evolution of Human Intelligence: The Roles of Brain Size and Mental Construction
  • K. Gibson
  • Psychology, Biology
    Brain, Behavior and Evolution
  • 2002
TLDR
A continuity model is presented that suggests that expanded human mental capacities primarily reflect the increased information processing capacities of the enlarged human brain including the enlarged neocortex, cerebellum, and basal ganglia.
...
...