Backward masking as a function of spatial frequency. A comparison of MMPI-identified schizotypics and control...

The present investigation relied upon a neurophysiological explanation of visual masking and compared the backward masking susceptibility of hypothetical schizotypal individuals with that of control subjects. Masking functions were assessed within two masking conditions: high spatial frequency (HSF) and low spatial frequency (LSF). Schizotypal subjects (those with a 2-7-8 or an 8-9 MMPI profile type) were compared with "psychiatric" control subjects (those with a spike 9 or a 4-9 profile type) and normal control subjects. Group differences were expected only in the transient-facilitating, LSF masking condition in this study's assessment of the hypothesis that a transient channel abnormality underlies the schizophrenia spectrum backward masking deficit. As predicted, schizotypal subjects displayed greater masking susceptibility in the LSF transient-facilitating condition as compared with the HSF, sustained-facilitating condition that produced no group differences. These results suggest that multichannel neurophysiological models of masking may help to direct research designed to gain an increased understanding of the specific nature of the spectrum masking deficit.