Date of Award
Doctor of Philosophy (PhD)
Dr. Daphne Maurer
This thesis examined the ability of the three-month-old infant to recognize and discriminate photographs of faces and facial expressions, and what information he perceives and processes when he is exposed to a face. It also investigated the effects of previous experience with 1 three-dimensional face and whether or not infants would generalize their knowledge of the real face of the mother to a photograph of the same face. Two experimental techniques, the visual preference and the habituation paradigms, were used. With the visual preference paradigm (Experiments 1 and 6), infants showed evidence of discriminating a photograph of the mother's face and a photograph of another female's face. These results imply that infants generalized what they knew about the real face of the mother to a picture of the same face.
After the visual preference test of Experiment 1, each infant was habituated to the photograph of his mother's face and then tested with photographs of the habituated face and a new face. Infants again showed evidence of discrimination. However, whereas in the visual preference test infants looked longer at the photograph of the mother than at that of a novel stranger, after habituation to the mother's photograph they looked longer at the photograph of a novel stranger. This change suggests that a preference for a novel stimulus may develop only after extensive experience with the familiar stimulus and thus involve a finer process of recognition than that involved in a preference for a familiar stimulus.
Although previous studies have not found discrimination of photographs of strangers before four and a half months of age, the author suspects that infants may show this discrimination at an earlier age if they were provided with extensive experience with a photograph of a stranger in the Laboratory. After infants were habituated to a photograph of a stranger they were given a recognition test. Infants showed evidence of discriminating between dissimilar strangers (Experiment 2) and between similar strangers (Experiment 3).
The discrimination of facial expressions posed by the same persons was tested next. The only other study which has found some evidence of discrimination of facial expressions at three months of age used expression posed by a male stranger. However, given the results of Experiments 1 to 3 one would expect that three-month-olds could discriminate facial expressions more readily on a familiar face--the mother's--than on a stranger's. Infants were habituated to either a frowning expression or a smiling expression, posed by the mother (Experiment 4) or by a female stranger (Experiment 5), and subsequently tested with the habituated and novel expressions. Infants showed evidence of discriminating the expressions regardless of whether they were posed by the mother or by a stranger. Yet, a greater number of infants showed the discrimination when the expressions were posed by the mother than by the stranger. These data thus indicate that three-month-olds can recognize a frowning or a smiling face after they are exposed to either for a period of time, especially when those expressions are posed by a familiar face like the mother's.
Sex differences were found when infants were habituated to the mother's expressions (Experiment 4) and when the tests involved discriminating the mother's face from a stranger's (Experiments 1 and 6), i.e., whenever the face of the mother was the stimulus or one of the stimuli. Hence, the author proposes that these sex differences may be the result of differences in the way mothers interacts with male and female infants.
Finally, in Experiment 7 three-month-old infants were presented with a life-size photograph of a face to determine what features they would fixate. Infants looked longer at the area of the eyes than at any other area of the face, even though they scanned the entire face. The discrimination data from Experiments 4 and 5 and the scanning data of Experiment 7 suggest that by three months of age infants perceive and process same internal features of the face.
The most general implication of the findings of this dissertation is that at least by three-months of age the areas of the brain responsible for processing and integrating complex arrays, like faces, are functioning and that some memory for such arrays is already present.
Barrera, Maria Eugenia C., "Face Perception and Memory in the Three-Month-Old Infant" (1978). Open Access Dissertations and Theses. Paper 699.