neurbiology of male friendships

7/31/2019 Neurbiology of Male Friendships

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Bearing in mind that this is still in its infancy, broadly speaking the

systems involved in friendship and bonding are the oxytocin,

vasosuppression and opiod systems.

As parents, we all heard of oxytocin round the birth of children.expansion of the affectional system deployed

in mother-infant bonding to incorporate other contexts

of social-affiliative relationships

a variety of clinical studies have implicated opioids in

autism (Bouvard et al., 1995). Treatment with naltrexoneproduces some clinical benefits and alters biochemical

profiles in a subset of autistic children. More recentstudies also have begun to explore the role of oxytocin

in autism (Insel, 1997). Studies in autistic adults suggest

that deficits in oxytocin may be correlated with

some symptoms of autism (Modahl et al., 1998), and

there is a report that increased gregariousness may follow

oxytocin treatments.

I like the opiod system theoryexperiments on mammals suggest that

friendship and love activate the receptor sites in the brain that opiates like

morphine and heroin lock into. Its possible that this explains the pain of

heartbreakgoing cold turkey from smack and having your true lovewalk out on you seem to be triggering the same part of the brain.

In primates, monkeys and apes, male group relationships seem to trigger

the opiod system in a slightly different way. Broadly, and lots of this is to

do with male status in the group and male-on-male aggression, males

who are happy and high status form good bonds with the group and get

an opiod reward trigger. Lower status males on the receiving end ofaggression tend to feel less affiliated to the group, have lower levels of

testosterone (to do with an opiod/sexual system interactions) andas thereview paper puts it: If the endogenous opioids serve as the "glue" for

social cohesion, then the attraction of life in the social group for

subordinate males is lost, and this may further explain why it is mainly

males of low rank that are more likely to leave their natal group in the

wild.

Basically, if males primates operated alone, this would be the entirety of

their experienceif youre low status, you stay low status. The failure to

get rewards depresses testosterone, you stay on the outside unless youshut up and submit.


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However. Recent studies on various ape and monkey males show

something to counter this depressingly eternal position in the social

ranking hierarchy. Scientists from Gttingen and Leipzig have discovered

that among macaques, a direct connection exists between male bonds andsocial success. Together with researchers at the Max Planck Institute for

Evolutionary Anthropology in Leipzig, Dr. Oliver Schlke and Prof. Julia

Ostner of Gttingen Universitys Courant Research Centre Evolution of

Social Behaviour have spent several years looking at the evolution of

social relationships among Assamese macaques in Thailand. The

researchers have now demonstrated for the first time that the strength of amales social bonds with other generally unrelated macaques of the same

sex has an impact on its social rise and, ultimately, the number of hisprogeny.

The closer a males relationships to other males the more frequently he

is successful in forming coalitions against other males. The male that

maintained the closest three bonds within the group in autumn 2006

steadily rose in status and today holds sway at the top of the hierarchy

together with its best friend, says Dr. Schlke. At the same time, males

that did not invest in friendships have steadily lost ground in the status

stakes, or never managed to move up at all.

Researchersincluding Oliver Schlke, an evolutionary biologist at theUniversity of Gttingenfind that every male in the group has a few

other males he interacts with more than others.

Males groom friendly males bodies frequently. Often, they groom areas

that an individual could groom himself. The grooming seems to work to

foster these bonds, says Schlke. The hygiene aspect was only one part

of it.

The bonds can lead to the forming of coalitions, where a group of malesmight fight another male to improve rank and social status, he has found.

The interesting thing is that these coalitions can help pull up low-

ranking individuals and help high-ranking males stay where they are,

says Schlke. Both things are going on at the same time.

Social support has

documented health benefits, and the absence of positive

social interactions or social bonds typically is associatedwith both physical and mental illness (Reite


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and Boccia, 1994; Ryff and Singer, 1998; Sperling

and Berman, 1994; Henry and Wang, 1998; Knox and

Uvnas-Moberg, 1998).

Forced social separations or the absence of social attachments

can trigger stress, anxiety, fear and even depression(Sachseret al., 1998).

Everyone needs a best friend, even chimpanzees. A decade-longstudy shows that nearly all adult male chimps form enduring socialbonds with other males, exchanging back scratches,sharing meat,and generally chumming around.

On average these bonds lasted seven years, saysJohn Mitani, aprimatologist at the University of Michigan, who observedchimpanzees in Uganda several months a year for 10 years.

The colony, in the jungles of Kibale National Park, is about threetimes the size of other chimpanzee populations in Africa, but is nomore social than others, he says.

For the study, Mitani spent a block of time recording theinteractions of a specific adult male chimp, including every

individual he interacted with, while notinggrooming behaviour.Females tend to leave their colony once they reach maturity andtherefore forge fewer social bonds, Mitani says.

As with human friendship, the strongest bonds seemed to bebased on mutual respect. Chimpanzees that groomed each otherfor roughly equal amounts of times tended to stay friends longer.

Brotherly love

Fraternity also played an important role in chimpanzee friendships,Mitani found. Animals that shared a mother were more likely toform lasting bonds than other pairs. However, chimpanzees with acommon father weren't any more likely to become buddies.

Nearly every chimpanzee that Mitani tracked formed at least onelong-term social bond, and some had multiple "best friends". Out of35 males, two never formed close friendships with other adultsduring the study period. However, both found friendship in a

younger, still adolescent brother, Mitani notes.
http://www.newscientist.com/article/dn11694-chimp-cooperation-goes-beyond-family.htmlhttp://www.newscientist.com/article/dn11694-chimp-cooperation-goes-beyond-family.htmlhttp://www.newscientist.com/article/dn11694-chimp-cooperation-goes-beyond-family.htmlhttp://sitemaker.umich.edu/mitanihttp://sitemaker.umich.edu/mitanihttp://sitemaker.umich.edu/mitanihttp://www.newscientist.com/article/dn15058-chimps-compile-nixonstyle-enemies-list.htmlhttp://www.newscientist.com/article/dn15058-chimps-compile-nixonstyle-enemies-list.htmlhttp://www.newscientist.com/article/dn15058-chimps-compile-nixonstyle-enemies-list.htmlhttp://www.newscientist.com/article/dn15058-chimps-compile-nixonstyle-enemies-list.htmlhttp://sitemaker.umich.edu/mitanihttp://www.newscientist.com/article/dn11694-chimp-cooperation-goes-beyond-family.html


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Exactly why chimpanzees form these stable bonds is unknown,Mitani says. It could be that having a best friend boostsreproductive success or survival somehow. But this will require"staying out there to see who does what with whom, and how often,and counting up the babies," he says.

Joan Silk, a primatologist at the University of California in LosAngeles, notes that chimp friendships aren't so different from thebaboon she studies.

Equitable grooming and sisterhood seemed to determine friendshipsamong female baboons in Botswana, she says. "These similaritiessuggest that there are common principles for building strong bondswhich extend across species."
http://www.sscnet.ucla.edu/anthro/faculty/silk/http://www.sscnet.ucla.edu/anthro/faculty/silk/http://www.sscnet.ucla.edu/anthro/faculty/silk/

neurbiology of male friendships

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