May 5 (HealthDay News) -- Genetics influence how a person makes a decision based on whether their options are presented to them in a positive or negative way (framing effect) -- such as being told there is an 80 percent chance of surviving or a 20 percent chance of dying during an operation, U.K. researchers report.
In a previous study, the research team from University College London (UCL) found that an area of the brain called the amygdala -- involved in processing emotions -- becomes active when people are making decisions influenced by the framing effect.
In this new study, the UCL researchers found that a person's genetic makeup appears to at least partly influence their susceptibility to the framing effect and their amygdala's response.
"We know that people from across a variety of cultures are susceptible to biases when making decisions, and that even with training, these biases are hard to overcome," Dr. Jonathan Roiser, of the UCL Institute of Cognitive Neuroscience, said in a Wellcome Trust news release. "This implies that hard-wired genetic influences might play an important role in determining how susceptible different individuals are to the framing effect."
In this study, 30 volunteers were given money and gambling options presented in a positive or negative way. Those with two copies of the short variant of the serotonin transporter gene were significantly more susceptible to the framing effect than those with two copies of the long variant of the gene.
The serotonin transporter gene is involved in the recycling of serotonin, a neurotransmitter that's essential for communication between nerve cells. The gene has been shown to affect the response of the amygdala.
"This one gene cannot tell the whole story, however, as it only explains about 10 percent of the variability in susceptibility to the framing effect. What determines the other 90 percent of variability is unclear. It is probably a mixture of people's life experience and other genetic influences," Roiser said.
The study was expected to be published in an upcoming issue of the Journal of Neuroscience.
SOURCE: Wellcome Trust, news release, May 5, 2009