What we see is relative
Human faces send out a surprising number of signals that can be interpreted by others. A face tells us whether a person is young or old, male or female, happy or sad. An American team of psychologists has now asked whether and how our perceptual ability is shaped by the faces that surround us in our social environment.
Images: University of Nevada
Previous research has shown that the way a face is recognized can be strongly influenced by showing the person a different image of that face. Scientists from the Department of Psychology at the University of Nevada, led by Michael A. Webster have now been able to show that the assessment of strange faces can change rapidly and also depends on which faces were seen shortly beforehand. In the current ie of Nature the American psychologists report their results.
In their experiments, Webster and his colleagues exposed several groups of subjects to what they called morphed images. Morphing is the almost imperceptible transformation of an object (face, body, etc.) into another object (face, body, etc.).) into another. This is done by the computer through calculations. The scientists morphed three different pairs of faces: each was an image continuum between the extremes of man and woman, European and Japanese face, and on a scale from disgust to surprise. In this way they wanted to find out how the test persons assess the intermediate stages. Are there z. B. a huge leap between male and female, just as we decide, for example, with colors at a very specific point, this is red and this is green, even if the differences are only slight?
First, the subjects had to find out which face was in the middle of the man-woman continuum, i.e. was actually androgynous. This they found out quite accurately. However, if they had been shown a male face beforehand, the "neutral" middle and they already classified the androgynous image as female. If a female face was presented first, it was exactly the opposite. In the case of the faces on the scale european resp. Japanese face, this effect was also observed, as well as in the disgust-surprise scale.
In addition, the researchers were interested in whether the interpretation of a face was influenced by categories that applied to the perceiver himself. Here, the assignment of pictures according to gender showed that the test subjects tended to be more inclined to their own gender. Such a tendency could also be confirmed in the case of ethnic affiliation. Here, a European and a Japanese test group were first subjected to a test. The same test was then administered to two different groups of Japanese subjects. Once this was a group of students who had been in the USA for a long time, the other group had been there for only two weeks. Here, too, it turned out that the perception threshold of the Japanese students, who had already had a longer stay in the USA, had approached that of their European colleagues.
Psychologists ame that the brain adapts to faces that appear regularly and repeatedly. Their characteristics did not lead to increased nervousness. Only when significant deviations from the average are registered do they attract increased attention.