Agriculture, Food and Beverage

Forget social lives, our brain size could all be down to diet

A tree laden with apples stands in an orchard in Kressbronn near Lindau at lake Bodensee, southern Germany August 20, 2014. EU fruit and vegetable growers will get financial aid of up to 125 million euros ($167 million) to help them cope with Russia's ban on most Western food imports, which has created a glut of produce in peak harvest time, the European Commission said on Monday. Russia has declared a one-year embargo on meat, fish, dairy, fruit and vegetables from the United States, the European Union, Canada, Australia and Norway in retaliation for Western economic sanctions over Moscow's actions in Ukraine. The EU funding will cover produce such as tomatoes, apples, cauliflowers, mushrooms, grapes, cucumbers, strawberries and blackcurrants, which lack storage options and have no immediate alternative markets to make up for the absence of Russia.    REUTERS/Michaela Rehle (GERMANY - Tags: AGRICULTURE BUSINESS FOOD POLITICS) - RTR432MI

Diet, not social life, may be the driver of brain size evolution, a new study suggests. Image: REUTERS/Michaela Rehle

James Devitt
Deputy Director of Media Relations , New York University
Share:
Our Impact
What's the World Economic Forum doing to accelerate action on Agriculture, Food and Beverage?
The Big Picture
Explore and monitor how Agriculture, Food and Beverage is affecting economies, industries and global issues
A hand holding a looking glass by a lake
Crowdsource Innovation
Get involved with our crowdsourced digital platform to deliver impact at scale
Stay up to date:

Agriculture, Food and Beverage

Diet, not social life, may be the driver of brain size evolution, a new study suggests. The findings call into question “the social brain hypothesis,” which argues that humans and other primates are big-brained because of their sociality.

The findings, which appear in the journal Nature Ecology and Evolution, reinforce the notion that both human and non-human primate brain evolution may be driven by differences in feeding rather than in socialization.

“Are humans and other primates big-brained because of social pressures and the need to think about and track our social relationships, as some have argued?” asks James Higham, assistant professor of anthropology at New York University. “This has come to be the prevailing view, but our findings do not support it—in fact, our research points to other factors, namely diet.”

“Complex foraging strategies, social structures, and cognitive abilities, are likely to have co-evolved throughout primate evolution,” adds Alex DeCasien, a doctoral candidate and lead author of the study in the journal Nature Ecology and Evolution. “However, if the question is: ‘Which factor, diet or sociality, is more important when it comes to determining the brain size of primate species?’ then our new examination suggests that factor is diet.”

The social brain hypothesis sees social complexity as the primary driver of primate cognitive complexity, suggesting that social pressures ultimately led to the evolution of the large human brain. While some studies have shown positive relationships between relative brain size and group size, other studies which examined the effects of different social or mating systems have revealed highly conflicting results, raising questions about the strength of the social brain hypothesis.

In the new study, researchers, including Scott Williams, an assistant professor of anthropology, examined more than 140 primate species—or more than three times as many as previous studies—and incorporated more recent evolutionary trees, or phylogenies. They took into account food consumption across the studied species—folivores (leaves), frugivores (fruit), frugivores/folivores, and omnivores (addition of animal protein)—as well as several measures of sociality, such as group size, social system, and mating system.

The findings show that brain size is predicted by diet rather than by the various measures of sociality—after controlling for body size and phylogeny. Notably, frugivores and frugivore/folivores exhibit significantly larger brains than folivores and, to a lesser extent, omnivores show significantly larger brains than folivores.

The results don’t necessarily reveal an association between brain size and fruit or protein consumption on a within-species level; rather, they are evidence of the cognitive demands required by different species to obtain certain foods.

“Fruit is patchier in space and time in the environment, and the consumption of it often involves extraction from difficult-to-reach-places or protective skins,” DeCasien says. “Together, these factors may lead to the need for relatively greater cognitive complexity and flexibility in frugivorous species.”

Don't miss any update on this topic

Create a free account and access your personalized content collection with our latest publications and analyses.

Sign up for free

License and Republishing

World Economic Forum articles may be republished in accordance with the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Public License, and in accordance with our Terms of Use.

The views expressed in this article are those of the author alone and not the World Economic Forum.

Share:
World Economic Forum logo
Global Agenda

The Agenda Weekly

A weekly update of the most important issues driving the global agenda

Subscribe today

You can unsubscribe at any time using the link in our emails. For more details, review our privacy policy.

Brazil's smallholder farmers can benefit from digital traceability — here's how 

Clara Clemente Langevin and Erica Dias

February 29, 2024

About Us

Events

Media

Partners & Members

  • Join Us

Language Editions

Privacy Policy & Terms of Service

© 2024 World Economic Forum