Sixty-six college students read two chapters from a contemporary novel while their eye movements were monitored. The eye movement data were analyzed to identify factors that influence the location of a reader's initial eye fixation on a word. When the data were partitioned according to the location of the prior fixation (i.e., launch site), the distribution of fixation locations on the word (i.e., landing site distribution) was highly constrained, normal in shape, and not influenced by word length. The locations of initial fixations on words can be accounted for on the basis of five principles of oculomotor control: A word-object has a specific functional target location, a saccadic range error occurs that produces a systematic deviation of landing sites from the functional target location, the saccadic range error is reduced somewhat for saccades that follow longer eye fixations, there exists oculomotor variability that is a second, non-systematic source of error in landing sites, and the oculomotor variability increases with distance of the launch site from the target.

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An analysis of over 40,000 eye fixations made by college students during reading indicates that the frequency of immediately refixating a word following an initial eye fixation on it varies with the location of that fixation. The refixation frequency is lowest near the center of the word and positively accelerating with distance from the center. The data are well fit by a parabolic function. Assuming that refixation frequency is related to the frequency of successful word identification, the observed curvilinear relation results naturally from models that postulate a linear decrease in acuity with retinal eccentricity. A single letter difference in fixation location in a word can make a sizeable difference in the likelihood of refixating that word. The effects of word length and cultural frequency on the frequency of refixating are also examined.McConkie, Kerr, Reddix, Zola, & Jacobs EYE MOVEMENT CONTROL DURING READING: II. FREQUENCY OF REFIXATING A WORDDuring reading, people fixate more frequently near the centers of words than near the beginnings and ends (Rayner, 1979). O'Regan (1981) proposed a Convenient Viewing Position hypothesis, stating that readers learn to send their eyes to the centers of words because, across the words in a language, that location is optimal for word identification. Due to the rapid drop in visual acuity with distance from the center of the fovea, together with the fact that letters bounded by spaces are more perceptible (Bouma, 1978;Jacobs, 1987), the letters of a word are maximally identifiable when the eyes are near the word's center. O'Regan further suggested that the further the eyes lie from the Convenient Viewing Position, the greater the probability that a second eye fixation on the word will be required for identification. This prediction was confirmed in a word identification study (O'Regan, 1984), which found that the frequency of making a second fixation on a word is minimized when the initial fixation is near the center of that word. Furthermore, the frequency of refixating increases as the distance of the first fixation from the center of the word increases. We refer to this relationship as the Word Refixation Frequency Curve, or simply as the word refixation curve. The existence of a word refixation curve in word identification tasks has been replicated (O'Regan, Levy-Schoen, Pynte, & Brugaillere, 1984) and there is some evidence that it may also be present in the eye fixation pattern made during reading (Blanchard & McConkie, cited by O'Regan & Levy-Schoen, 1987).

College students read a passage presented in AlTeRnAtInG cAsE on a CRT while their eye movements were monitored. During certain saccades, the case of every letter was changed (a became A, B became b). This change was not perceived and had no effect on eye movements. Apparently visual features of the type which specify the difference between upper-and lowercase letters are not integrated across fixations during reading. 221One of the most well-established facts about reading concerns the saccadic nature of eye movements. About four times a second, the eye is cast to a new location, supposedly giving the reader a new glimpse of the test. Although the reader has the experience of passing somewhat smoothly along the line in reading, in fact, the eye is relatively still over 90% of the time, with movements requiring only 20-40 msec occuring about 4 times/sec (Woodworth, 1938).This fact about eye movements gives rise to a basic question about reading: How is information from discrete glimpses of the text orchestrated into a smoothly proceeding reading process? How is information integrated across fixations?The need for some sort of combining of information seems obvious from our ability to perceive a coherent world from such discrete input. However, a study by Rayner (1975) specifically demonstrated the problem in reading. While subjects were reading a paragraph displayed on a computer-controlled cathode-ray tube (CRT) a saccade was identified that was likely to center the eye on a preselected word location. The contents of that word location were then changed during that same saccade. Thus, the word lying in the fovea on one flXation, following the display change, was different from the word which had occupied that location in the text on the prior fixation. If the prior fixation had been within 12 letter positions to the left of the critical word location, the fixation following the change (which was centered on the changed word) was longer than if no change had occurred. This was taken as evidence that the change in stimulus from one fixation to the next had affected the processing that occurs during reading; presumably this caused some disruption of the process by which information from successive fixations is

The experimental investigation reported in this article deals with the process of extracting visual information during reading. Subjects read texts that manipulated the predictability of a target word through the choice of an immediately preceding word. Spelling errors were also introduced into some of the target words. A detailed examination was made of the subjects' eye-movement patterns. Several aspects of eye behavior were analyzed to determine if contextual constraint and misspelling influenced perception during reading. Subjects exhibited no differences in the frequency of fixating the target words in the high-constraint and low-constraint conditions. However, the fixation of the target words was shorter in the high-constraint condition. In addition, fixation durations and regression probabilities associated with misspelled words were also significantly inflated. The eye-movement patterns showed that minimal spelling errors often disrupted reading, even when the misspelled words were highly predictable. These results suggest that language constraint does expedite processing during reading; furthermore, they suggest that such facilitation does not necessarily occur through a reduction in the visual analysis of the text.To understand how perception takes place in any particular task, two fundamental questions must be dealt with. First, it is necessary to determine what is serving as the stimulus information for perception. Second, it is necessary to identify the perceptual activities by which the extraction and use of this stimulus information yields its effects. The first of these questions is the most directly empirical in nature. If experimental research can specify the information that is "picked up" for a perceptual activity under precise conditions, then an understanding of the mental events of perception under those conditions can be addressed more profitably. Without sound evidence about the stimulus information extracted, further theorizing about perceptual activities is somewhat meaningless.The purpose of this research was to determine whether contextual information influences what visual information is noticed and used during reading. At any given moment in time, when a person is engaged in the cognitive activity of reading, there are a great many sources of information that can be used to identify meaning. Such information might include the reader's linguistic awareness, the reader's background knowledge, the reader's understanding of the meaning of the text up to that given moment, and, of course, the visual characteristics of the segment of text the reader is currently considering.The research reported here specifically addressed theThe research described in this paper was supported by Grant MH 32884 from the National Institute of Mental Health to George McConkie, and by National Institute of Education Contract HEW-NIE-C-400-76-0116to the Center for the Study of Reading. The author wishes to thank George W. McConkie for his comments on earlier versions of the manuscript. Copies of this paper ca...