Monday, January 22, 2007
Activation of Brain Region Predicts Altruism
Duke University Medical Center researchers have discovered that activation of a particular brain region predicts whether people tend to be selfish or altruistic.
"Although understanding the function of this brain region may not necessarily identify what drives people like Mother Theresa, it may give clues to the origins of important social behaviors like altruism," said study investigator Scott A. Huettel, Ph.D., a neuroscientist at the Brain Imaging and Analysis Center.
Results of the study appear Sunday, January 21, in the advance online edition of Nature Neuroscience and will be published in the February 2007 print issue of the journal. The work was funded by the National Institutes of Health.
Altruism* describes the tendency of people to act in ways that put the welfare of others ahead of their own. Why some people choose to act altruistically is unclear, says lead study investigator Dharol Tankersley, a graduate student in Huettel's laboratory.
In the study, researchers scanned the brains of 45 people while they either played a computer game or watched the computer play the game on its own. In both cases, successful playing of the game earned money for a charity of the study participant's choice.
The researchers scanned the participants' brains using a technique called functional magnetic resonance imaging (fMRI), which uses harmless magnetic pulses to measure changes in oxygen levels that indicate nerve cell activity.
The scans revealed that a region of the brain called the posterior superior temporal sulcus was activated to a greater degree when people perceived an action - that is, when they watched the computer play the game - than when they acted themselves, Tankersley said. This region, which lies in the top and back portion of the brain, is generally activated when the mind is trying to figure out social relationships.
The researchers then characterized the participants as more or less altruistic, based on their responses to questions about how often they engaged in different helping behaviors, and compared the participants' brain scans with their estimated level of altruistic behavior. The fMRI scans showed that increased activity in the posterior superior temporal sulcus strongly predicted a person's likelihood for altruistic behavior.
According to the researchers, the results suggest that altruistic behavior may originate from how people view the world rather than how they act in it.
"We believe that the ability to perceive other people's actions as meaningful is critical for altruism," Tankersley said.
The scientists suggest that studying the brain systems that allow people to see the world as a series of meaningful interactions may ultimately help further understanding of disorders, such as autism or antisocial behavior, that are characterized by deficits in interpersonal interactions.
The researchers are now exploring ways to study the development of this brain region early in life, Tankersley said, adding that such information may help determine how the tendencies toward altruism are established.
C. Jill Stowe, a decision scientist in Duke's Fuqua School of Business, also participated in the research. [Source: Duke University]
Based on the Nature Neuroscience 'Brief Communication':
Altruism is associated with an increased neural response to agency
Dharol Tankersley, C Jill Stowe and Scott A Huettel
Although the neural mechanisms underlying altruism remain unknown, empathy and its component abilities, such as the perception of the actions and intentions of others, have been proposed as key contributors. Tasks requiring the perception of agency activate the posterior superior temporal cortex (pSTC), particularly in the right hemisphere. Here, we demonstrate that differential activation of the human pSTC during action perception versus action performance predicts self-reported altruism.
From Eric Strong's "The Evolution of Altruism":
The concept of altruism is best understood through example: an African wild dog voluntarily "babysitting" the pups of a pack, while the pack's hunters search for food; a bird giving an alarm call to warn others of an approaching hawk, and thus drawing attention to itself in the process; a man jumping into a swimming pool to save a drowning stranger. While these acts obviously require different levels of sacrifice on the part of the altruist, on average we can expect all of them to decrease his number of expected offspring.
This is where the paradox of altruism arises. If, by definition, altruism reduces an individual's fitness, we should expect Charles Darwin's natural selection to select against the altruistic trait and eventually reduce its representation within a population to zero.
Scott A. Huettel is co-author of "Functional Magnetic Resonance Imaging":
"This textbook provides a true introduction to functional magnetic resonance imaging (fMRI), which has become the dominant research technique in cognitive neuroscience. Although there is extraordinary interest in fMRI among researchers and instructors alike, two problems have hampered the study of this technique. First, existing texts are targeted toward practicing scientists in the field and assume a level of expertise not possessed by most students. Second, most students do not have access to fMRI equipment and data, so they have no opportunity to gain hands on experience. This textbook overcomes these limitations by presenting a comprehensive overview of all aspects of fMRI, designed with undergraduate students, graduate students and beginning researchers in mind. The authors' goal was to create a book that is sufficiently scientifically rigorous for scientists in the field, but also accessible enough to be easily read and understood by beginning students. The book can be used as the primary text for classes in fMRI, or as a secondary text for cognitive neuroscience, research methods or other courses."
A review of Kindness in a Cruel World: The Evolution of Altruism by Nigel Barber:
Beginning with Darwin's theory of evolution, Barber shows how the original notion of a dog-eat-dog world where survival of the fittest is the only rule must now be modified by new findings on altruism. In bees, for example, the workers evolve without reproductive ability and exist only for the good of the hive and the propagation of the queen bee's genes. In addition, vampire bats will spontaneously share food through regurgitation, evidently so that the favour will be returned when food sources are scarce. In humans, reciprocal arrangements depend on trust, so moral emotions, like guilt, embarrassment, resentment, and pride, have evolved to guard against the temptation to cheat, which would destroy the basis of trust on which so much depends. Barber brings the revealing insights of evolutionary psychology to these examples and more, and delves into related issues including sex differences in kindness, new approaches to rehabilitating criminals, the connection of kindness to health, and the political manifestations of altruism in the environmental movement.
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