Friday, April 15, 2016
Why do we sometimes decide to take risks and other times choose to play it safe? In a new study, Caltech researchers explored the neural mechanisms of one possible explanation: a contagion effect.
The work is described in the March 21 online early edition of the Proceedings of the National Academy of Sciences.
In the study led by John O’Doherty, professor of psychology and director of the Caltech Brain Imaging Center, 24 volunteers repeatedly participated in three types of trials: a “Self” trial, in which the participants were asked to choose between taking a guaranteed $10 or making a risky gamble with a potentially higher payoff; an “Observe” trial, in which the participants observed the risk-taking behavior of a peer (in the trial, this meant a computer algorithm trained to behave like a peer), allowing the participants to learn how often the peer takes a risk; and a “Predict” trial, in which the participants were asked to predict the risk-taking tendencies of an observed peer, earning a cash prize for a correct prediction. Notably in these trials the participants did not observe gamble outcomes, preventing them from further learning about gambles.
O’Doherty and his colleagues found that the participants were much more likely to make the gamble for more money in the “Self” trial when they had previously observed a risk-taking peer in the “Observe” trial. The researchers noticed that after the subjects observed the actions of a peer, their preferences for risk-taking or risk-averse behaviors began to reflect those of the observed peer–a so-called contagion effect. “By observing others behaving in a risk-seeking or risk-averse fashion, we become in turn more or less prone to risky behavior,” says Shinsuke Suzuki, a postdoctoral scholar in neuroscience and first author of the study.
Saturday, April 02, 2016
March 6, 2015
Men with borderline testosterone levels have higher rates of depression and depressive symptoms than the general population, new research finds. The results will be presented Saturday, March 7, at ENDO 2015, the annual meeting of the Endocrine Society in San Diego.
"Over half of men referred for borderline testosterone levels have depression. This study found that men seeking management for borderline testosterone have a very high rate of depression,depressive symptoms, obesity and physical inactivity," said principal study author Michael S. Irwig, MD, FACE, associate professor of medicine and director of the Center for Andrology in the Division of Endocrinology at George Washington University in Washington, DC. "Clinicians need to be aware of the clinical characteristics of this sample population and manage their comorbidities such as depression and obesity."