Abstract

Spatial-frequency channel interactions were investigated within a Crawford masking paradigm. Test stimuli were presented before, during, and after mask onset. Virtually no masking effects were seen when test and mask frequencies differed by a factor of 3. The temporal response characteristics of low-spatial-frequency targets were evidenced by transient peaks in the threshold curve near mask onset, while high-spatial-frequency test stimuli showed sustained response characteristics with elevations throughout mask exposure. When mask and test stimuli were the same frequency, maximal masking was obtained. Masking curves for complex masks composed of two components also showed this elevation, but it was not as robust as that obtained when the target and mask were the same frequency. This suggests that the second component had inhibited the effectiveness of the component in the mask, which was identical to the test spatial frequency. Interactions found among the frequency components occurred only at points of maximal masking. For low-spatial-frequency test stimuli, interactions were found near mask onset and were dependent on mask contrast level. High-spatial-frequency test stimuli showed interactions which were independent of mask contrast throughout mask exposure.

© 1988 Optical Society of America