With National Science Foundation support Dr. Gary Raney will purchase a Dual-Purjkinje-Image eyetracker with autostaging and video upgrades. It has a rated accuracy of 3 minutes of arc and a response time of less than 1 ms which allows fixation position to be sampled at a high rate. The enhanced video upgrade provides the experimenter with alignment feedback so the system may be continually monitored without disturbing the subject. Three minutes of arc represents 1/4 the width of a character in a typical reading study and this will allow Dr. Raney to determine a subject's letter focus with a high degree of accuracy. The proposed research will explore how passages of text are stored and retrieved from memory. In each of several studies, individuals will read a passage once and then read the passage a second time. A common finding is that people read a text faster during a second reading and this is known as a repetition effect. The size of the repetition effect will be used as a measure of how much the first reading facilitates processing during the second. Two contrasting theoretical models of text repetition effects have been proposed. One argues that the effect is based on a word's abstract meaning - that `grass` will have a priming effect if, in a second passage the word `lawn` is substituted. The other argues that priming is more word and less meaning specific. To discriminate between these models, individual features of texts will be systematically manipulated between first and second readings. How these changes influence reading behavior and repetition effects will be measured by examining readers' eye movements. The eye tracker will also serve a more general function and be employed for specific experiments conducted by other faculty members. It will also be available to undergraduates for specific research projects.
