Odor senses apparently dependent on emotions of our fellow human beings

Emotional facial expressions influence the smell perception
That odors have a significant influence on interpersonal emotions, has long been known. Scientists at the Ruhr-Universität Bochum (RUB) have now discovered that conversely, the emotional expression of other people also influences the perception of smell. The basis for this effect seems to be "the activity of a brain area, which is responsible for the smell and is already active before the perception of a smell," the researchers report.

How positive or negative we perceive a scent, according to the scientists is significantly influenced by the facial expression of the people around us. "If we see someone who makes a disgusted face, because he has a bad smell in the nose, comes one yourself the smell is also more unpleasant, "says Dr. Patrick Schulze of the RUB the effect. The results of the researchers were published in the scientific journal "Scientific Reports".

The facial expression of others influences the perception of smells. (Image: ruigsantos / fotolia.com)

Effects of facial expressions on the sense of smell examined
With the help of functional magnetic resonance imaging (fMRI), the research team has Patrick Schulze, dr. Anne-Kathrin Bestgen and Prof. Dr. med. Boris Suchan examines whether emotional information has an impact on the perception of odors. 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 expression and then let the participants rate one of twelve smells," reports the RUB.

Happy facial expression makes smells more pleasant
The facial expression considered had a significant effect on the perception of the fragrances. Thus, the same scent was rated more pleasantly when a happy face had been shown instead of a disgusted face. According to the researchers, this was "true for aromas like caramel or lemon, as well as for the smell of sweat or garlic." Only the smell of fecal matter did not enhance a positive facial expression.

Expectation affects perception
According to the RUB scientists, the reason for the effects of facial expressions on smell perception is in a particular part of the olfactory brain - the piriform cortex. This turns on before the perception of an odor and process what we see. He creates an expectation of how the smell will smell. This in turn influences how we actually feel the scent. The fMRI data showed that the cells of the piriform cortex became active even before there was a smell in the air.

Earlier investigations could not uncover the connection, since the test persons were always presented with smells and pictures at the same time, explain the researchers. "Only by examining the interplay of odors and visual information separately from each other did it become apparent that the piriform cortex is active before the actual smell," says Professor Suchan. Another study will now examine the role of the piriform cortex in body perception, with researchers suggesting a social component. (Fp)