1989 — 1992 |
Mcconkie, George |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
A Theory of Eye Position Control in Reading @ University of Illinois At Urbana-Champaign
One way to study people's mental processes as they read or examine pictures, charts, or maps is to monitor their eye movements and see where they look, in what order, and for how long. However, interpretation of the pattern of eye movements requires a theoretical framework that describes how the eyes respond to mental activities. This research builds on the beginnings of such a theory, constructed by McConkie and his associates as a consequence of their recent research. The theory, so far, consists of a description of where the eyes are sent during reading and perhaps during other tasks. This description assumes that higher cognitive processes select an object (in the case of reading, a word) to be the target for the next eye movement. The theory then describes four principles that operate to determine where the eyes will actually land: 1. The center of the selected object serves as a target for the eye movement. 2. There is a systematic error in the eye movement control system, called the "saccadic range error," that results in the eyes undershooting their target on long saccades and overshooting it on short saccades. This error function is quantifiable. 3. There is also unsystematic error, or random variability, in eye movement control. It produces a normally-distributed spread of oculomotor "landing sites." 4. The amount of spread of the landing sites is a non-linear increasing function of the saccade length. This project will test the theory in a number of ways, seeking to identify its limits, examining how the parameters of the model must be modified in order for it to describe accurately data from different people and conditions, and determining whether it can be applied to tasks other than reading and to displays of materials other than text. Finally, if the theory proves to be robust, it will be used to develop an algorithm that will indicate, for each eye movement, which word was actually serving as the target. Such an algorithm will make future eye movement research more powerful, since it will provide a means of separating aspects of the data related to higher cognitive processes from those that only reflect properties of the oculomotor system. This research will provide a quantitative description of one aspect of normal oculomotor functioning, thus contributing to our understanding of the relation between mental activity and eye movement control. This description may ultimately be useful clinically as a basis for identifying abnormalities in eye movement control.
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