Gaze discrimination is unimpaired in schizophrenia

Interpersonal communication is largely dependent on interpretation of facial expression and emotion. Difficulties in face processing, and more specifically in gaze discrimination, have been described in schizophrenic patients. According to Baron-Cohen (Mindblindness. M.I.T. Press, Cambridge, MA, 1995), gaze discrimination relies on the functioning of a specific cognitive module, the Eye Direction Detector (EDD). It has been proposed [Rosse et al. (1994) Gaze discrimination in patients with schizophrenia: preliminary report. American Journal of Psychiatry 151, 919-921] that an impairment in gaze discrimination is present in schizophrenia, and plays a fundamental role in inducing the paranoid symptoms reported by many patients. However, in the previous studies, gaze direction detection and interpretation of gaze have never been completely dissociated. The present experiment attempts to test the schizophrenics' skill in a simple gaze direction detection task. A series of photographic portraits of models looking at different directions have been presented to 22 schizophrenic patients and 36 control subjects. For each portrait subjects were asked to determine whether gaze was directed to the right or to the left by pressing a keyboard key. A forced choice paradigm was used. No differences were reported between schizophrenic patients and control subjects. That is, in the present paradigm, schizophrenic patients did not show any specific impairment in detecting the direction of gaze of the portraits. The results are discussed according to the notion that a dissociation is present in schizophrenia between implicit and explicit processes. The present case illustrates how the more automatic elementary functions, such as the detection of gaze direction, may be spared in schizophrenic patients, whereas explicit cognitive functions are likely more affected.