Brain detects happiness
more quickly than sadness
Wednesday, June 17,
2009
People make value judgements about others based on their facial
expressions. A new study, carried out be Spanish and Brazilian
researchers, shows that – after looking at a face for only 100
milliseconds – we can detect expressions of happiness and surprise
faster than those of sadness or fear.
Our brains get a first impression of people's overriding social
signals after seeing their faces for only 100 milliseconds (0.1
seconds). Whether this impression is correct, however, is another
question. Now an international group of experts has carried out an
in-depth study into how we process emotional expressions, looking
at the pattern of cerebral asymmetry in the perception of positive
and negative facial signals.
The researchers worked with 80 psychology students (65 women and 15
men) to analyze 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.
The results, published in the latest issue of the journal
Laterality, show 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", explains Aznar-Casanova.
The two faces
of the brain
This research study adds to previous ones, which had revealed
asymmetries in the way the brain processes emotions, and enriches
the international debate in cognitive-emotional neuroscience in
terms of how to define the exact way in which human beings process
these facial expressions.
People make deductions from the expressions on people's faces.
"These inferences can strongly influence election results or the
sentences given in trials, and have been studied before in fields
such as criminology and the pseudoscience of physiognomy", the
neuroscientist tells SINC.
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 (the right,
withdrawal, and the left, approach).
"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.
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FECYT - Spanish Foundation for Science and Technology
Thanks to FECYT - Spanish
Foundation for Science and Technology for this article.