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Biomedical subjects

D C Hay

Publications and source records attributed to D C Hay.

8 recordsLinked to original sources

Face processing in psychiatric conditions.

Functional models of face processing have indicated that dissociations exist between the various processes involved, e.g. between familiar face recognition and matching of unfamiliar faces, and between familiar face recognition and facial expression analysis. These models have been successfully applied to the understanding of the different types of impairment that can exist in neuropsychological patients. In the present study, aspects of face processing in psychiatric patients were investigated in relation to Bruce & Young's (1986) model. Based on this functional model different predictions can be made. We contrast here the impaired expression analysis hypothesis, which is that psychiatric patients would show a deficit in facial expression recognition, but not in facial identity recognition or unfamiliar face matching, with the generalized deficit hypothesis, that patients would be impaired on all tasks. These hypotheses were examined using three forced-choice tasks (facial recognition, facial expression recognition, and unfamiliar face matching) which were presented to schizophrenic and depressed patients, and to non-patient controls. Results showed that schizophrenic patients performed at a significantly lower level than non-patient controls on all three tasks, supporting the generalized deficit hypothesis.

Adult

Routes through the face recognition system.

Two experiments are reported which seek to examine the proposition first put forward by Hay and Young (1982), that recognition of a known person after seeing his or her face proceeds through a series of sequentially organized stages. In both experiments subjects were shown a selection of famous and unfamiliar faces and required to state whether each face was familiar. They were then asked to recall semantic information and the person's name. Of all the possible response types, only some are predicted by models derived from Hay and Young (1982), and only these responses were observed in Experiment 1. In order to give as complete an account as possible of the slips and errors made by subjects, they were interrogated some days after completing the testing phase in Experiment 2. As in the first experiment, the results supported the view that distinct but successive stages are involved in everyday face recognition. The method developed here provides an extension of the "dairy" type of study of everyday recognition errors into laboratory conditions, which confirms the findings of studies of everyday errors and provides strong support for sequential models.

Adult

Facial neglect.

Following a stroke, a retired industrial chemist, K.L., complained that faces looked "different" and had become difficult to recognize. Investigation of this problem revealed that it particularly affected the left half of a face as seen by K.L. Defective recognition of this (left) half was found for normal faces, chimaeric faces, and for half-faces presented in isolation, whether upright or inverted. The problem was apparent for both internal and external facial features. Further studies with chimaeric faces demonstrated inattention to left-side features in K.L.'s judgements of facial expression and of resemblance between faces. Moreover, the left-half of a chimaeric face was affected even when it was itself forming part of the face positioned on the right in a display of two horizontally aligned chimaerics. K.L.'s spatial contrast sensitivity function was within normal limits for his age. He did not experience differential difficulty in recognizing the left side of everyday objects or of car-fronts (another stimulus class demanding within-category discrimination between visually similar items that display approximate left-right symmetry). He was also able to sort left or right half-stimuli correctly into the categories "human face", "dog face", or "tree". Although K.L. had a left visual field defect, the problem with faces occurred within otherwise intact parts of his field of vision. We suggest that his disorder can be considered a domain-specific form of unilateral neglect.

Aged

Configurational information in face perception.

A new facial composites technique is demonstrated, in which photographs of the top and bottom halves of different familiar faces fuse to form unfamiliar faces when aligned with each other. The perception of a novel configuration in such composite stimuli is sufficiently convincing to interfere with identification of the constituent parts (experiment 1), but this effect disappears when stimuli are inverted (experiment 2). Difficulty in identifying the parts of upright composites is found even for stimuli made from parts of unfamiliar faces that have only ever been encountered as face fragments (experiment 3). An equivalent effect is found for composites made from internal and external facial features of well-known people (experiment 4). These findings demonstrate the importance of configurational information in face perception, and that configurations are only properly perceived in upright faces.

Adult

Face-name interference.

Interference effects between the processing of simultaneously presented photographs of faces of familiar people and printed names of familiar people were investigated. Printed names interfered with identifying faces, whereas faces did not interfere with saying printed names (Experiments 1 and 3). In contrast, faces interfered more with name categorization than names interfered with face categorization (Experiments 2 and 4). Despite a priori reasons as to why faces might be thought to possess functional properties different from those of other visual objects, the observed effects are comparable to those found in object-word interference studies, with photographs of faces behaving like pictures of objects and printed people's names behaving like printed names of objects. In face naming tasks, the presence of related names produced more interference than did the presence of unrelated names (Experiment 1). This effect was examined in greater detail in Experiment 3, where we found that the effect arises when the face and the name belong to people of similar appearance. An effect of common category membership was not found in Experiment 3. Experiment 5, however, showed that names of people highly associated with the person whose face is presented also produce more interference than do names of unrelated people.

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