Washington, June 18: Our brains detect the expressions of happiness and surprise faster than those of sadness or fear, according to a study.
The finding springs from the efforts of an international team of Spanish and Brazilian researchers who studied how people process emotional expressions, looking at the pattern of cerebral asymmetry in the perception of positive and negative facial signals.
The research team worked with 80 psychology students, 65 women and 15 men, to analyse the differences between their cerebral hemispheres using the "divided visual field" technique, which is based on the anatomical properties of the visual system.
"What is new about this study is that working in this way ensures that the information is focused on one cerebral hemisphere or the other," J Antonio Aznar-Casanova, one of the authors of the study and a researcher at the University of Barcelona (UB), tells SINC.
Appearing in the journal Laterality, the findings suggest that the right hemisphere performs better in processing emotions.
"However, this advantage appears to be more evident when it comes to processing happy and surprised faces than sad or frightened ones," the researcher points out.
"Positive expressions, or expressions of approach, are perceived more quickly and more precisely than negative, or withdrawal, ones. So happiness and surprise are processed faster than sadness and fear," says Aznar-Casanova.
Previous studies have already shown that asymmetries in the way the brain process emotions.
Two theories are currently "competing" to explain the pattern of cerebral asymmetry in processing emotions.
The older one postulates the dominance of the right hemisphere in the processing of emotions, while the second is based on the approach-withdrawal hypothesis, which holds that the pattern of cerebral asymmetry depends upon the emotion in question, in other words that each hemisphere is better at processing particular emotions.
"Today there is scientific evidence in favour of both these theories, but there is a certain consensus in favour of the lateralisation of emotional processing predicted by the approach-withdrawal hypothesis," concludes Aznar-Casanova.
First Published: Thursday, June 18, 2009, 11:32