Visual recogition of dot-pattern bigrams: an extension and replication.

The study examined visual recognition of bigrams, each formed from a pair of "random" dot patterns, as a function of stimulus offset asynchrony and duration. The results replicate and extend those of an earlier study by showing that the effect of backward masking in vision, where the mask is actually a part of the preceding composite target, is limited to about 250 to 300 msec. This time interval is suggested as that required to complete the processing of that composite target. The results may be understood in terms of an interruption hypothesis, with selective attention and/or discontinuity detectors as mechanisms possibly involved in the masking process.