Evidence that focal processing involves a build-up of a visual object.

Abstract

Subjects were required to make one of three judgements when presented with a tachistoscopically displayed letter, and the PEST procedure was used to obtain point estimates of the stimulus exposure time required to yield a 50 per cent (corrected for chance) level of accuracy. The judgements were ordered in terms of the information required, and on the assumption that pattern recognition involves the build-up of an appropriate visual object (Neisser, 1967), it was predicted that as the visual representation required to make a judgement increased in detail, the exposure time required would also increase. The results showed that stimulus exposure time increased as subjects located at one of four positions, classified as angular or circular, and identified a letter from the set F,T,O,Q. The type of information required to make these judgements, changed from the figure-ground discrimination needed for location, to the detailed level of representation needed for identification. Therefore, the results supported the prediction and were taken as evidence that pattern recognition involves the build-up of a visual object. The judgements location, classification, and identification were also made on a letter from the set F,f,Q,q, but in this case the classification judgement required subjects to name the letter independent of its case. The results showed that naming was just as difficult as identifying and this suggested that the level of representation required to name the letter was the same as that required to identify it.