MASKING OF SPATIAL-FREQUENCY IN VISUAL MEMORY DEPENDS ON DISTAL, NOT RETINAL, FREQUENCY

Spatial frequency discrimination thresholds measured in a two-interval forced choice paradigm are virtually constant across inter-stimulus i ntervals ranging from 400 to 30,000 msec, demonstrating that an accura te representation of spatial frequency is maintained in short-term mem ory. This representation can be degraded by briefly flashing a grating during the retention interval, Moreover, this memory masking effect v aries with the spatial frequency of tile mask, suggesting that the mec hanisms used to store spatial frequency in memory are similar to low-l evel visual filters, In this paper we replicate those previous finding s and extend them by showing (1) that accurate memory for spatial freq uency lasts as long as 1 min; (2) that memory masking is based on dist al (c/cm), not retinal (c/deg), spatial frequency.