Gemini can not tell apart themselves in pictures. Nevertheless, they tend to help people who are more like themselves. Photo: Paola Bressan
Reading aloud Not the familiar faces of family members, but their own appearance is the most important standard in dealing with others: the more someone resembles one's own appearance, the more willing one is to help him, as two Italian researchers have shown. This inclination is considered the remnant of early humanity when it proved beneficial to support relatives. The self-reference is still amazing, especially because there were hardly any opportunities over the long stretches of human development history to closely inspect their own appearance. So far, it has been assumed that the internal standard for recognizing potential relatives is mainly composed of the faces of siblings and parents. In the early hunter-gatherer cultures there were no mirrors and thus no possibility to study one's own face with all its intricacies. Nevertheless, there is still a tendency to treat people who look similar and thus potential relatives differently than other people. The recognition of these relatives occurs according to popular theory by the search for similarities in their appearance with an internal reference? because who looks similar is somehow akin to a high probability. How the reference picture comes about and whether the reference is one's own face or the look of those with whom one lives together in childhood is so far unclear.

To investigate further, Bressan and Zucchi now had 17 monozygotic and 18 dizygotic twins paired with two pictures each to determine if they would help the person shown, or if they would recommend them to their twin as a spouse. The trick: The images were generated on the computer from a model face, which was fused with a photo of the subjects, so that the result was 35 percent of the subjects' face and 65 percent of the model face. Each participant was shown their own changed face and that of their twin.

In 63 and 64 percent of the cases, did the participants prefer the picture that came from their own face? even if the other was the only slightly different face of the identical twin. The researchers conclude that the internal standard is actually dominated by the self-image. Although the brain probably uses visual information about close relatives to generate the reference. However, as soon as data about their own appearance is available, the design is replaced by a refined version. Only in this way could a reliable reference be established for both the maternal relatives and the paternal ones? after all, you can never be sure that your siblings have the same father.

Paola Bressan and Guendalina Zucchi (University of Padua): Biology Letters, DOI: 10.1098 / rsbl.2008.0789 ddp / science.de? Ilka Lehnen-Beyel advertisement

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