Monkeys with larger friend networks have more gray matter

Nov 04, 2011 by Lin Edwards report
Barbary Macaques (Macaca sylvanus) at a monkeys park in Algeria

New research in the UK on rhesus macaque monkeys has found for the first time that if they live in larger groups they develop more gray matter in parts of the brain involved in processing information on social interactions.

The researchers, led by Jerome Sallet of Oxford University, said the results of the new study bear some similarities to research by other groups working with humans, that related to the extent of social interactions. These studies include recent work that suggested a link between the volume of some regions of the brain and the number of online friends people have in such as Facebook.

The new study observed 23 macaques in a number of groups of different sizes. The monkeys were kept in their groups for an average of over a year, and a minimum of two months. One monkey was alone in its cage, but in all the other groups, which had from two to seven individuals, a heirarchy developed in which an individual's rank depended on the monkey's ability to form successful social interactions, such as friendships and partnerships.

The study used (MRI) to compare the brains of the monkeys, and the results showed that in the temporal areas of the brain associated with social interaction skills, around a five percent increase in the volume of gray matter was found for each additional group member. The regions of the brain that increased in volume included the temporal pole, temporal cortex, and the inferior and rostral temporal gyri.

The researchers also compared the brains of male monkeys at various levels in the dominance-based heirarchy and found a number of brain areas, particularly the and inferior temporal sulcus, were enlarged in males of higher rank.

The research demonstrated that the social networks caused the changes in the brain (rather than enlarged influencing position in the social network, or the size of the network) because the scientists manipulated the size and makeup of the groups over a period of several months, and observed the changes in the brains of the monkeys.

Earlier research has shown that the brain shows plasticity, which means it can change in volume in different regions in response to environmental changes or acquisition of new skills or knowledge. Research had not previously shown brain plasticity in relation to social networking skills.

The paper was published in the journal Science on 4th November.

Explore further: Ask yourself: Will you help the environment?

Related Stories

Monkeys' grooming habits provide clues to how we socialise

Sep 30, 2009

(PhysOrg.com) -- A study of female monkeys' grooming habits provides new clues about the way humans socialise. New research reveals a link between the size of the neocortex in the brain, responsible for higher-level ...

Subordinate monkeys more likely to choose cocaine over food

Apr 06, 2008

Having a lower social standing increases the likelihood that a monkey faced with a stressful situation will choose cocaine over food, according to a study at Wake Forest University School of Medicine. More dominant monkeys ...

Brain biology may dictate social networks

Jan 04, 2011

(PhysOrg.com) -- A new study by a Northeastern University researcher and her colleagues indicates that the size of a certain part of the human brain plays a significant role in determining the breadth of social ...

Recommended for you

Male-biased tweeting

12 hours ago

Today women take an active part in public life. Without a doubt, they also converse with other women. In fact, they even talk to each other about other things besides men. As banal as it sounds, this is far ...

Developing nations ride a motorcycle boom

14 hours ago

Asia's rapidly developing economies should prepare for a full-throttle increase in motorcycle numbers as average incomes increase, a new study from The Australian National University has found.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

RobertKarlStonjek
1 / 5 (1) Nov 04, 2011
OK, next time a rhesus wants to friend me on Facebook I'll say yes ~ his/her grey matter depends on it!!!

More news stories

Male-biased tweeting

Today women take an active part in public life. Without a doubt, they also converse with other women. In fact, they even talk to each other about other things besides men. As banal as it sounds, this is far ...

Not just the poor live hand-to-mouth

When the economy hits the skids, government stimulus checks to the poor sometimes follow. Stimulus programs—such as those in 2001, 2008 and 2009—are designed to boost the economy quickly by getting cash ...

Archaeologists, tribe clash over Native remains

Archaeologists and Native Americans are clashing over Indian remains and artifacts that were excavated during a construction project in the San Francisco Bay Area, but then reburied at an undisclosed location.