Emotional facial expressions influence the perception of smell
It has long been known that smells have a significant impact on interpersonal emotions. Scientists at the Ruhr University Bochum (RUB) have now found that the other way around, the emotional facial expression of other people also influences the smell perception. The basis for this effect seems to be “the activity of an area of the brain that is responsible for smelling and that becomes active even before a smell is perceived,” the researchers report.
How positive or negative we perceive a fragrance is, according to the scientists, largely influenced by the facial expressions of the people around us the smell is also immediately unpleasant, ”explains Dr. Patrick Schulze from RUB the effect. The results of the researchers were published in the scientific reports.
Effects of facial expressions on the sense of smell examined
Using functional magnetic resonance imaging (fMRI), the research team led by Dr. Patrick Schulze, Dr. Anne-Kathrin Bestgen and Prof. Dr. Boris Suchan examines whether emotional information influences the perception of smells. To do this, they analyzed how the brain processes emotional information and smells together. In their experiments, they showed the participants "first a photo of a person with a happy, neutral or disgusted facial expression and then had the participants rate one of twelve smells," reports the RUB.
A happy facial expression makes smells more pleasant
The facial expression under consideration showed clear effects on the perception of the scents in the test subjects. The same smell was rated more pleasant if a happy face was shown instead of a disgusted face. According to the researchers, this was true "for aromas such as caramel or lemon as well as for the smell of sweat or garlic." Only the smell of faeces could not have been enhanced by a positive facial expression.
Expectation affects perception
According to the RUB scientists, the reason for the effects of facial expressions on olfactory perception is to be found in a certain part of the olfactory brain - the piriform cortex. This activates itself before you perceive a smell and processes what we see. He creates an expectation of how the smell will smell. This in turn influences how we actually feel the fragrance. The fMRI data showed that the cells of the piriform cortex became active even before there was an odor in the air.
Earlier studies were unable to reveal the connection, since the subjects were always presented with smells and pictures at the same time, the researchers explain. "It was only by examining the interplay of smells and visual information at different times that it became apparent that the piriform cortex is active before the actual smell," says Professor Suchan. In another study, the role of the piriform cortex in body awareness should now be examined, with the researchers suspecting a social component. (fp)