The locus of the word-priority effect in a target-detection task

When subjects are required to monitor verbal displays for predesignated targets, their reaction time for word targets is less than that for subcomponents of words, such as letters. One explanation for this word-priority effect is that encoding of words is completed prior to encoding of their constituent letters. An alternative explanation is that it takes longer to compare letter targets with encoded displays than it does word targets. In this experiment, target set size and display illumination were independently manipulated during word and letter target-detection tasks, and interactions between factors were examined using the assumptions of Sternberg's (1969) additive factor approach. It was found that the magnitude of the word-priority effect increased with an increase in target set size, but not with a decrease in display illumination. This suggested that the effect occurs at a comparison stage rather than at an encoding stage in the information processing chain.