Face Detection and Its Relationship with Visual Contrast Detection in Schizophrenia

Face perception is impaired in schizophrenia. While a socially and ecologically important function, face perception receives inputs from visual processing, a more basic perceptual function also impaired in schizophrenia. How basic visual processing impairment contributes to face perception impairment is not well understood. In this study we examined face detection, an early stage of face perception, as a function of visual contrast in schizophrenia. We also examined visual contrast detection, a basic visual process. For face detection, subjects indentified the location (left or right) of a face imbedded in a larger image. For contrast detection, subjects indentified the location (left or right) of a low-contrast grating within a uniform luminance background. To vary task difficulty, the contrast level of the images used for both tasks was systematically manipulated. Performance of patients (n=27) and controls (n=20) were acquired and compared. Performance accuracies of patients were significantly lower than those of controls for face detection (p=.039) but not contrast detection. In patients, performance accuracies were significantly correlated between face detection and contrast detection (r=0.70). Patients' face detection performance was moderately correlated with PANSS negative subscale scores (r=-0.42). This pattern of results suggests the contributions of basic visual signal to impaired face processing in schizophrenia. These results also suggest a potential association of face perception impairment with negative psychotic symptom status.