Subverting perceptions - testosterone promotes 'cuddling', not just aggression

Aubrey Kelly, assistant professor of psychology at Emory University and lead author of the study, said: "We think this is the first time we have shown that testosterone can directly promote non-sexual prosocial behavior in the same person, in addition to aggression.

Neuroscientist Richmond Thompson of Emory University's Oxford College is a co-author of the study

Kelly's lab has recently focused on the neurological effects of oxytocin using experimental rodent models

In addition to shared research interests, Kelly and Thompson share a home as a married couple

Most human studies show that testosterone enhances aggressive behavior

To test this question, Kelly's lab conducted experiments with Mongolian gerbils, rodents that form durable mates and raise their young together

In one experiment, a male gerbil was introduced to a female gerbil

Kelly said: "Instead, we were surprised that a male gerbil became more lovable and kissed his mate

In a follow-up experiment a week later, the researchers conducted a resident intrusion test

"Typically, one male will chase another male that enters the cage, or try to avoid it," Kelly said

However, this friendly behavior suddenly changed when the original male subjects were injected with testosterone again

The researchers reasoned that because male subjects experienced a surge in testosterone when they were with their partners, this not only rapidly increased positive social responses to them, but also allowed men to behave more prosocially in the future, even as circumstances changed, and they There was another male present

In a sense, the lab experiments slowed down the process that the males went through almost simultaneously in the wild

If a competitor enters its burrow, the gerbil may experience another testosterone surge that will immediately help adjust his behavior so he can fend off the competitor and protect his young
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As the social world changes, testosterone appears to help animals rapidly switch between prosocial and antisocial responses
.

The current study also looked at how testosterone and oxytocin interact biologically
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The results showed that males who received testosterone injections had more oxytocin activity in their brains when interacting with their partners, compared to males who did not receive injections
.

Kelly said: "We know that the oxytocin and testosterone systems overlap in the brain, but we really don't know why
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Taken together, our findings suggest that one reason for this overlap may be that they can work together to promote Prosocial behavior
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" Hormones aren't just an "on" or "off" button that regulates behavior, it seems to play a more subtle role
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"It's like a complex dashboard where one dial might need to be moved up a little while the other needs to be moved down
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"

Human behavior is far more complex than Mongolian gerbils, but the researchers hope their findings provide the basis for complementary research in other species, including humans
.

"Our hormones are the same, and they even act on the same parts of the brain," Thompson said
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So understanding how hormones like testosterone help other animals adapt to rapidly changing social environments will not only help us understand the impact biological fundamentals of their behavior, but also to predict and ultimately understand how the same molecules in the human brain help shape our responses to the social world around us
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"

Jose Gonzalez Abreu, a former research specialist in Kelly's lab, is a co-author of the study
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This work was supported by the National Science Foundation
.

Beyond sex and aggression: testosterone rapidly matches behavioral responses to social context and tries to predict the future