Master of Arts (MA)
Faculty of Arts
Left-right differences in visual field accuracy obtained in studies of tachistoscopic recognition have been typically discussed in terms of a covert post exposure scanning process derived from the horizontal eye movements (EM) habitually used in reading. Further, some evidence exists that indicates the occurrence of EM concomitant with the recognition process. By monitoring EM during a representative recognition task, the present study attempted to establish the relation between overt EM elicited by the task, and response accuracy. Using a projection tachistoscope (duration 100 msec.), 8 female Ss were presented with a random trial series of 8-element letter, number, and symbol arrays exposed bilaterally, and 4 letter arrays exposed unilaterally. In a second trial series, bilateral and unilateral letter arrays were presented at a 1 sec. duration. A high resolution corneal reflection technique was used to detect the latency and direction of EM. The pattern of recognition accuracy for alphanumeric stimuli generally conformed to the results of previous investigations based on grouped data. Marked individual variation was noted in the present results, suggesting a source of variability worthy of analysis. Response accuracy obtained for symbol arrays was highly variable and demonstrated a lack of lateral disparity, indicating an unstructured encoding process for this material. The post exposure EM was established as a reliable phenomenon, identical in topography to the EM evoked with the stimulus present. However, the EM behaviour did not relate to recognition accuracy, a result that does not limit the use of reading EM as a model for the scanning process. Rather, the lack of relation does indicate that overt EM are not involved in that process. Further implications of the EM and recognition results for theory and future research are discussed in detail.
McRae, R. Cameron, "Post-Exposural Eye Movements and Lateral Differences in Tachistoscopic Recognition" (1972). Theses and Dissertations (Comprehensive). 1552.