Visual search with imperfect recognition

A task involving both the search for and recognition of one of two possible critical elements embedded in a set of noise elements was investigated with the aid of a mathematical model. The model consists of three processes, these being search, recognition, and decision. The first of two experiments attempted to show the operation of two separate bias parameters in the decision process. While the results were in the right direction, the data did not unequivocally establish the necessity of two bias parameters. In the second study, it was found that while a S’s ability to find a critical element in a display decreased as the number of noise elements in the display increased, his ability to recognize which critical element it was after finding it remained constant. This result was interpreted as supporting a strictly all-or-none view of the search process.