Looking in the eyes to discriminate

Abstract

Studies showed that individual differences in encoding speed as well as looking behaviour during the encoding of facial stimuli can relate to differences in subsequent face discrimination. Nevertheless, a direct linkage between encoding speed and looking behaviour during the encoding of facial stimuli and the role of these encoding characteristics for subsequent discrimination has not been investigated yet. In the present habituation study, an eye-tracker was used to investigate how individual differences in encoding speed (number of habituation trials) relate to individual differences in looking behaviour on faces and the internal facial features (eyes, nose, and mouth) during encoding as well as discrimination. Forty infants habituated to a photograph of a female face. In a subsequent dishabituation phase, a new face was followed by the familiar one. As expected, the results showed that most of the infants were able to habituate to the face and that they managed to discriminate between the new and the familiar face. Furthermore, correlations and analyses of variance showed that individual differences in encoding during habituation related to differences in looking behaviour during habituation as well as dishabituation. Slower-habituating infants could better discriminate between the new and the familiar face and showed a higher interest in the eyes during habituation as well as dishabituation than faster-habituating infants. These data underline that individual differences in encoding speed relate to individual differences in looking behaviour and that increased looking behaviour to important social cues might help subsequent discrimination.