Culture may explain why brains have become bigger

November 08, 2018

A theory called the cultural brain hypothesis could explain extraordinary increases in brain size in humans and other animals over the last few million years, according to a study published in PLOS Computational Biology by Michael Muthukrishna of the London School of Economics and Political Science and Harvard University, and colleagues at the University of British Columbia and Harvard University.

Humans have extraordinarily large brains, which have tripled in size in the last few million years. Other animals also experienced a significant, though smaller, increase in brain size. These increases are puzzling, because brain tissue is energetically expensive: that is, a smaller brain is easier to maintain in terms of calories. Building on existing research on learning, Muthukrishna and colleagues analytically and computationally modeled the predictions of the cultural brain hypothesis and found that this theory not only explains these increases in brain size, but a variety of other relationships with group size, learning strategies, knowledge and life history.

The theory relies on the idea that brains expand to store and manage more information. Brains expand in response to the availability of information and calories. Information availability is affected by learning strategies, group size, mating structure, and the length of the juvenile period, which co-evolve with brain size. The model captures this co-evolution under different conditions and also describes the specific and narrow conditions that can lead to a take-off in brain size--a possible pathway that led to the extraordinary expansion in our own species. The authors called this set of predictions the cumulative cultural brain hypothesis. These theories were supported by tests using existing empirical data. Taken together, the findings may help explain the rapid expansion of human brains and other aspects of our species' life history and psychology.

"This is a brand-new theory to explain the evolution of the human brain as well as brains more generally. It shows how various characteristics of a species are actually intrinsically connected through a common evolutionary process," says Muthukrishna. "The limits to larger brains is our ability to birth them, but as this theory suggests, this process is ongoing - we're now expanding our juvenile period, hitting a new biological limit in our ability to reproduce at an older age".

Next, the researchers plan to test the predictions made by the theory that relate to individual, rather than social, learning, as well as developing extensions to the theory.
-end-
Peer-reviewed; Simulation/modelling; N/A

In your coverage please use this URL to provide access to the freely available article in PLOS Computational Biology: http://journals.plos.org/ploscompbiol/article?id=10.1371/journal/pcbi.1006504

Citation: Muthukrishna M, Doebeli M, Chudek M, Henrich J (2018) The Cultural Brain Hypothesis: How culture drives brain expansion, sociality, and life history. PLoS Comput Biol 14(11): e1006504. https://doi.org/10.1371/journal.pcbi.1006504

Funding: The authors received no specific funding for this work.

Competing Interests: The authors have declared that no competing interests exist.

PLOS

Related Learning Articles from Brightsurf:

Learning the language of sugars
We're told not to eat too much sugar, but in reality, all of our cells are covered in sugar molecules called glycans.

When learning on your own is not enough
We make decisions based on not only our own learning experience, but also learning from others.

Learning more about particle collisions with machine learning
A team of Argonne scientists has devised a machine learning algorithm that calculates, with low computational time, how the ATLAS detector in the Large Hadron Collider would respond to the ten times more data expected with a planned upgrade in 2027.

Getting kids moving, and learning
Children are set to move more, improve their skills, and come up with their own creative tennis games with the launch of HomeCourtTennis, a new initiative to assist teachers and coaches with keeping kids active while at home.

How expectations influence learning
During learning, the brain is a prediction engine that continually makes theories about our environment and accurately registers whether an assumption is true or not.

Technology in higher education: learning with it instead of from it
Technology has shifted the way that professors teach students in higher education.

Learning is optimized when we fail 15% of the time
If you're always scoring 100%, you're probably not learning anything new.

School spending cuts triggered by great recession linked to sizable learning losses for learning losses for students in hardest hit areas
Substantial school spending cuts triggered by the Great Recession were associated with sizable losses in academic achievement for students living in counties most affected by the economic downturn, according to a new study published today in AERA Open, a peer-reviewed journal of the American Educational Research Association.

Lessons in learning
A new Harvard study shows that, though students felt like they learned more from traditional lectures, they actually learned more when taking part in active learning classrooms.

Learning to look
A team led by JGI scientists has overhauled the perception of inovirus diversity.

Read More: Learning News and Learning Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.