Eye Guidance Research Articles

The existence of a center of gravity effect during reading

Many experiments have shown the existence of a “global effect” during peripheral target fixation tasks: whatever the position of the target in peripheral vision, the eye lands first near the center of gravity of the global peripheral configuration. The present paper investigates whether such an effect might be present during text reading. The experiments reported tested whether the eye's initial landing position in a test word was affected by the presence of other words or stimuli in the peripheral visual field. Results showed that essentially the information present up to seven characters from the beginning of the test word influenced the eye's landing position in the test word. Moreover, the position where the eye landed corresponded to the location of the cortically weighted center of gravity of this critical peripheral configuration. On the basis of these results, new hypotheses were proposed to explain saccade length programming and eye guidance during reading.

How Do Readers Know Where to Look Next? Local Information Distributions Influence Eye Fixations

Skilled readers' eye movements were recorded as they inspected sentences in preparation for comprehension questions. The sentences were written around target words that had uneven distributions of information, in that the words were predictable, given either the first few letters or the last few letters. Some parts of these words can be described as being more important than others for successful word recognition, and the experiments asked whether inspection patterns reflect the uneven distributions. Four types of ten-letter word were used: words with highly redundant endings (e.g. engagement), with moderately redundant endings (e.g. repatriate), with moderately redundant beginnings (e.g. superstore), and words with informative beginnings and endings (e.g. amalgamate). Redundancy was defined operationally in terms of the number of possible completions of a word given the first few or last few letters. A highly redundant ending is therefore one that occurs frequently and cannot be used to identify the word. Words gaining just one fixation received this fixation nearer to the word's centre than in the case of the first fixation upon words gaining two fixations. The single fixation also had a longer duration, giving support to the notion of a convenient viewing location, which, when achieved, can lead to a net saving in inspection time. In the case of words with redundant endings gaining just one fixation, the fixation was nearer to the beginning of the word than in the case of words with informative endings, and this influence of word type upon the location of the first fixation was interpreted in favour of the parafoveal processing hypothesis of eye guidance during reading.

The Span of Letter Recognition of Good and Poor Readers

THIS STUDY investigated the span of letter recognition for good and poor readers during a reading task. Sixteen fifth-grade children read passages from a cathode-ray tube as their eye movements were monitored. On selected fixations during reading, letters in certain regions of the display were replaced by other letters. This manipulation provided erroneous text in specific regions of the visual field. The results of the study indicate that both groups acquire letter information from a region of text extending from two letters to the left of the center of the fixation through to about six or seven letters to the right. There was no evidence to suggest that skilled readers utilize letter information from a wider region of text than do less able readers. The findings have significant implications for theories of information processing and theories of eye guidance in reading, especially as the present investigation is the first to compare the performance of good and poor readers when peripheral information is disrupted but foveal information remains intact.

La visée du regard sur un mot isolé

Summary : Where does the eye land in isolated words ? What mechanisms determine where the eye-fixates words during reading ? The processing taking place during the reading of connected text is probably much too complex for a simple answer to be given to this question. We decided to investigate oculomotor behaviour during the reading of words isolated from any syntactic and semantic context. The data obtained in the experiment showed that the eye's first fixations are concentrated around a position located either in the first half of the word or near the middle of the word depending on the particular experimental conditions. These results suggest that there is a normal goal within a word. On the basis of results obtained by presenting the words either on the left or the right side of the fixation point, we concluded that eye guidance depends on cognitive information specifie to reading words as well as the purely visual characteristics of the word. The results were discussed in the light of O'Regan's (1981) hypothesis that there is a « Convenient Viewing Position » (CVP, just to the left of the middle of the word) which allows words to be identified more rapidly than other locations. Our data together with those from O'Regan's studies suggest the hypothesis that subjects generally seek to reach the CVP but they are seldom successful, mainly when the word is presented on the left side of the fixation point. Key words : eye movements, fixation within a word, reading.

Manipulation of stimulus onset delay in reading: evidence for parallel programming of saccades.

On-line eye movement recording of 12 subjects who read short stories on a cathode ray tube enabled a test of direct control and preprogramming models of eye movements in reading. Contingent upon eye position, a mask was displayed in place of the letters in central vision after each saccade, delaying the onset of the stimulus in each eye fixation. The duration of the delay was manipulated in fixed or randomized blocks. Although the length of the delay strongly affected the duration of the fixations, there was no difference due to the conditions of delay manipulation, indicating that fixation duration is under direct control. However, not all fixations were lengthened by the period of the delay. Some ended while the mask was still present, suggesting they had been preprogrammed. But these "anticipation" eye movements could not have been completely determined before the fixation was processed because their fixation durations and saccade lengths were affected by the spatial extent of the mask, which varied randomly. Neither preprogramming nor existing serial direct control models of eye guidance can adequately account for these data. Instead, a model with direct control and parallel programming of saccades is proposed to explain the data and eye movements in reading in general.

Eye Guidance in Reading: Fixation Locations within Words

Three broad categories of models of eye movement guidance in reading are described. According to one category, eye movements in reading are not under stimulus or cognitive control; the other two categories indicate that cognitive activities or stimulus characteristics are involved in eye guidance. In this study a number of descriptive analyses of eye movements in reading were carried out. These analyses dealt with fixation locations on letters within words of various lengths, conditional probabilities that a word will be fixed given that a prior word was or was not fixated, and average saccade length as a function of the length of the word to the right of the fixated word. The results of these analyses were supportive of models which suggest that determining where to look next while reading is made on a nonrandom basis.

Peripheral and cognitive components of eye guidance in filled-space reading.

Five undergraduates read aloud three pages of text a day for 10 days. One page of text each day had interword spaces filled with a black letter-like filler, one with a red filler, and one was normal (control). Results showed that (1) red fillers produced a reading rate significantly below normal text, (2) black fillers yielded a significantly lower reading rate than red fillers, and (3) with practice, the reading rate for the black-filled condition rose significantly. Testing on Day 11 with an alternative filler form showed that a specific form was being learned with practice. Results were interpreted as support for both peripheral guidance of eye movement by physical cues and cognitive guidance involving reader-generated hypotheses about the text.

What guides a reader's eye movements?

Five categories of models of eye guidance in reading are described. Eye movement data from 10 college-age readers were analysed. Correlations between the lengths of successive saccades, between the durations of successive fixations, and between successive fixation durations and saccade lengths were very low. The number of fixations centering on a letter was related to the length of the word it was in. It is argued that eye movements in reading are under momentary, non-random control. Models attempting to account for eye movement data on a random basis, or by simple gain controls or visual buffer monitoring are not found acceptable.

Experiments in binocular synchronization.

AS applied to eye guidance, Helmholtz's classical empirical theory of space perception1 contains two basic assumptions: first, that direction and location in space are learned by temporal association between visual and tactile experience, and second, that the two eyes are exactly conjugate in their response to visual stimuli. The second assumption is logically necessary because the theory of temporal association permits no time discrepancy between the two eyes in forming visual and tactual associations. If such binocular differences did occur, each eye would “learn” separate directions. We have set out to test this second assumption.