The variety of relations between spatial frequency and reaction time.

While stimuli of lower spatial frequency often result in faster responses, this is not invariably the case. Some individuals respond faster to high frequency stimuli on tasks for which most others respond faster to low frequency stimuli. Past experience can also determine the degree to which a low frequency stimulus will mask a high frequency stimulus. These observations suggest that the effects of spatial frequency on visual information processing are under the control of higher level cognitive operations.