Tuesday, June 15, 2010

Oxytocin Increases In-Group Empathy . . . and Aggression Toward Out-Groups

Over the last five years or so, there has been a ton of press about the potential of oxytocin (the "cuddle hormone") to increase empathy and kindness, even in men. Now we know that such results are limited to one's in-group.

As an example of the oxytocin makes people more kind idea, here is a 2007 article from PLoS ONE, "Oxytocin Increases Generosity in Humans":

Human beings routinely help strangers at costs to themselves. Sometimes the help offered is generous—offering more than the other expects. The proximate mechanisms supporting generosity are not well-understood, but several lines of research suggest a role for empathy. In this study, participants were infused with 40 IU oxytocin (OT) or placebo and engaged in a blinded, one-shot decision on how to split a sum of money with a stranger that could be rejected. Those on OT were 80% more generous than those given a placebo. OT had no effect on a unilateral monetary transfer task dissociating generosity from altruism. OT and altruism together predicted almost half the interpersonal variation in generosity. Notably, OT had twofold larger impact on generosity compared to altruism. This indicates that generosity is associated with both altruism as well as an emotional identification with another person.
You can read the whole article online.

Similar articles appeared earlier this year (2010) announcing that oxytocin can make even men more empathic, as reported by Time:

Psychiatrist Rene Hurlemann of Bonn University and neuroscientist Keith Kendrick of the Cambridge Babraham Institute were well acquainted with the power of oxytocin when it's released the way nature intended. What they wanted to determine is if it could be artificially administered to a person to manipulate feelings of empathy and perhaps even learning. "Both learning and empathy are part of what's known as social cognition," says Hurlemann. "That's our ability to feel what other people are feeling and take their point of view."

To test how oxytocin might affect those capabilities, Hurlemann and Kendrick ran a two-part experiment. In the first, 48 males were divided into two groups — half received an aerosol shot of oxytocin and half got a placebo — and then shown evocative pictures of things like a crying child, a grieving man and a girl hugging a cat. They were then asked to describe how deeply they were feeling the emotions associated with the pictures. On the whole, the men in the oxytocin group exhibited "significantly higher emotional empathy levels" than those in the placebo group. This, despite the fact that all of the volunteers were able to describe and understand what was going on in the pictures and what the people in them were probably feeling.

In the second part of the experiment, the subjects were given a simple on-screen exercise that tested their ability to observe certain details in images or words. Sometimes correct answers were indicated by a green circle and incorrect ones by a red one; other times a happy face and a disapproving face were substituted. All of the men learned more quickly when the faces were used, but the difference was particularly marked among those in the oxytocin group. "You got a combined effect," Hurlemann says. "You enhance empathy and in the process, you enhance social learning."

Sounds great. And for use in increasing empathy in relationships and families it might turn out to be a huge breakthrough. But what about the rest of a person's life? How will this impact someone at work, or in sports, or on the road?

A new study suggests that oxytocin may increase aggressiveness toward out-group members (people with no close ties). Could oxytocin be part of the ethnocentric impulse?

This comes from Science Daily:

Neurobiological Cause of Intergroup Conflict: 'Bonding Hormone' Drives Aggression Towards Competing out-Groups

ScienceDaily (June 14, 2010) — Researchers at the University of Amsterdam provide first-time evidence for a neurobiological cause of intergroup conflict. They show that oxytocin, a neuropeptide produced in the brain that functions as hormone and neurotransmitter, leads humans to self-sacrifice to benefit their own group and to show aggression against threatening out-groups. This finding qualifies the wide-spread belief that oxytocin promotes general trust and benevolence.

Results were published in the journal Science.

An important qualification of this research is that oxytocin, commonly referred to as the "bonding hormone," functions as a cause of defensive aggression -- aggression oriented towards neutralizing a threatening out-group. When the competing out-group was not considered a threat, oxytocin only triggered altruism towards one's own group. This finding provides a neurobiological explanation for the fact that conflicts between groups escalates when other groups are seen as threatening. When such threat is low, for example because there are (physical) barriers between the group territories, conflict escalation is less likely.

The evolution of altruism in intergroup conflict

The research team at the University of Amsterdam, directed by Dr. Carsten de Dreu, wondered why oxytocin would promote altruistic behavior. Whereas classic economic theory has difficulty accounting for altruism, an evolutionary perspective suggests that altruism functions to strengthen one's own group, from which the individual benefits in the long run. Because aggression towards competing out-groups helps one's own group to become relatively stronger, aggression is an indirect form of altruistic, loyal behavior towards one's own group.

Charles Darwin already observed that groups whose members are altruistic towards the own group have a greater likelihood to prosper, to survive, and spread. The researchers reasoned that if this is true, neurobiological mechanisms should have evolved that sustain altruism towards the own group, and aggression towards competing other groups. The discovery that oxytocin promotes altruism towards the own group, and aggression towards threatening out-groups, supports this evolutionary perspective.

Journal Reference:

  1. C. K. W. De Dreu, L. L. Greer, M. J. J. Handgraaf, S. Shalvi, G. A. Van Kleef, M. Baas, F. S. Ten Velden, E. Van Dijk, S. W. W. Feith. The Neuropeptide Oxytocin Regulates Parochial Altruism in Intergroup Conflict Among Humans. Science, 2010; 328 (5984): 1408 DOI: 10.1126/science.1189047

This just shows that we need to be careful about dispensing hormones without looking at all the implications. For example, based on this research, would giving oxytocin to a racist or homophobe make them more likely to be violent toward the group they fear (and racism and homphobia ARE fear-based behaviors)? Would a fearful sexist male be more so under the influence?

Science often does not ask these questions before moving forward with new drugs.

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