CHARLOTTESVILLE, Va., Aug. 10 (UPI) -- Biologists and psychologists have long known that light affects mood but a U.S. study indicates light may also play a role in modulating fear and anxiety.
University of Virginia researchers say experiments showed intense light increases fear or anxiety in mice, which are nocturnal, in much the same way that darkness can intensify fear or anxiety in humans.
"We looked at the effect of light on learned fear, because light is a pervasive feature of the environment that has profound effects on behavior and physiology," Brian Wiltgen, a professor of psychology, said. "Light plays an important role in modulating heart rate, circadian rhythms, sleep/wake cycles, digestion, hormones, mood and other processes of the body.
"In our study we wanted to see how it affects learned fear."
"Learned" fear is not innate but comes from experiences such as dangerous or bad situations, and this learning can protect us from dangers, researchers said.
"Studies show that light influences learning, memory and anxiety," Wiltgen said. "We have now shown that light also can modulate conditioned fear responses.
"We showed that light itself does not necessarily enhance fear, but more light enhances learned fear," Wiltgen said. "It may be similar to a person learning to be more fearful in the dark."
