UBC Theses and Dissertations
The role of expectations in the feature integration process Butler, Deborah Lynne
According to Treisman (Treisman and Schmidt, 1982) feature detection occurs in parallel, while the correct integration of detected features into an object requires focal attention. She has proposed that in the absence of attention, subjects will perceive "illusory conjunctions", or invented objects constructed out of features actually present in a display. The present experiments were designed to examine how the presence of expectations might affect the feature integration process and the construction of illusory conjunctions. The results of these experiments suggest that expectations do affect the perception of simple objects: subjects make more illusory conjunctions in the absence of expectations, and the perception of expected objects is the most accurate. However, the data indicate that expectations do not exert this influence by guiding the feature integration process, because subjects do not tend to construct expected objects out of features appearing in a display. As a result, it is likely that expectations are influential not by determining the construction of object files, but by speeding up the identification of the features of expected objects, so that focal attention can be applied, and object files constructed, more efficiently. As a result, the perception of expected objects can be accurately accomplished in a shorter amount of time.