Information integration across eye movements.

The visual world contains more information than can be perceived in a single glance. Consequently, humans make eye and head movements and somehow construct a stable and continuous representation of the visual environment from these successive views. How this is accomplished has puzzled psychologists for over a century. The present research investigated the properties of transsaccadic integration, the integration of information across saccadic eye movements. The results of several experiments suggest that the mental representation of the environment that is constructed across eye movements is surprisingly schematic and undetailed, and based more on the contents of the current fixation than on one's memory for the contents of previous fixations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory for position and identity across eye movements.

Used a "transsaccadic" partial report procedure to measure memory for position and identity information across saccades. Delaying the partial-report cue after the eye movement had little effect on report accuracy. Mask presentation hindered recall only at the shortest delay. Accuracy was much higher when the letter array contained 6 letters than when it contained 10 letters. Intra-array errors were much more frequent than extra-array errors. These results suggest that memory across eye movements decays slowly, has a limited capacity, is maskable for a brief time, and retains identity information better than position information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual masking and visual integration across saccadic eye movements.

Studied visual masking and visual integration across saccadic eye movements in 4 experiments. In a 5th experiment, 4 randomly chosen dots from a 3?×?5 dot matrix were presented in 1 fixation, and 4 different dots from the matrix were presented in a 2nd fixation. Ss reported the location of the missing dot. When the 1st display was presented just before the saccade (as in Exps I–III), Ss accurately specified the missing dot location when the dots were presented to the same region of the retina but not when they were presented in the same place in space. When the 1st display was presented well before the saccade (as in Exp IV), Ss performed poorly regardless of retinal or spatial overlap. Results indicate the existence of a short-lived retinotopic visual persistence but provide no support for a spatiotopic visual persistence capable of fusing the contents of successive fixations. It is concluded that transsaccadic integration depends instead on an abstract memory that accumulates position and identity information about the contents of successive fixations. Results are discussed in relation to the work by M. L. Davidson et al (see record 1974-10245-001). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of phonological codes in integrating information across saccadic eye movements in Chinese character identification.

Prior research has generally assumed either that phonological codes do not contribute to Chinese character identification or that they do so only through a look-up process at the character level. In 3 experiments, a homophone seen parafoveally aided the identification of a target character that was fixated following an eye movement to the preview location. Moreover, high-frequency phonetically regular characters were named faster than high frequency, phonetically irregular characters. Thus, both lexical and sublexical phonological codes of Chinese characters are involved early in the process of character identification. Orthographic information from the preview was also used in character identification, as orthographically similar previews facilitated target identification as well. The evidence for the extraction of semantic information from parafoveal previews was mixed, as synonym previews facilitated in Experiment 2 but not in Experiment 1. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of spatial location in integration of pictorial information across saccades.

Identification of a fixated object in a visual display is facilitated by integrating information from a preview of that object in the periphery with information extracted on the subsequent foveal fixation (A. Pollatsek et al; see record 1985-16415-001). These experiments investigated the extent to which this integration is dependent on the spatial location of the information remaining constant. Two preview objects were presented in the periphery; Ss fixated that region and named a single target object that appeared in the same spatial location in which one of the two preview objects had been presented. Of primary interest was the facilitative effect when a preview object was identical to the target object as a function of whether they were in the same spatial location. Although there was a small effect of switching, there was still a substantial preview benefit even when the location of the identical object switched. There was also a preview benefit in conditions in which there were no eye movements and the preview and target objects were at least 5° apart. The process of object identification may be relatively insensitive to location information. Object information and location information coded fairly independently. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stable individual differences across images in human saccadic eye movements.

Individual differences in eye movements during picture viewing were examined across image format, content, and foveal quality in 3 experiments. Experiment 1 demonstrated that an individual's fixation durations were strongly related across 3 types of scene formats and that saccade amplitudes followed the same pattern. In Experiment 2, a similar relationship was observed for fixation durations across faces and scenes, although the amplitude relationship did not hold as strongly. In Experiment 3, the duration and amplitude relationships were observed when foveal information was degraded and even removed. Eye movement characteristics differ across individuals, but there is a great deal of consistency within individuals when viewing different types of images. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Programming saccadic eye movements.

This article addresses questions about the preparatory processes that immediately precede saccadic eye movements. Saccade latencies were measured in a task in which subjects were provided partial advance information about the spatial location of a target fixation. In one experiment, subjects were faster in initiating saccades when they knew either the direction or amplitude of the required movement in advance compared to a condition with equal uncertainty about the number of potential saccade targets but without knowledge of the parameters required to execute the movement. These results suggest that the direction and amplitude for an upcoming saccade were calculated separately, and not in a fixed serial order. In another experiment, subjects appear to have programmed the saccades more holistically—with computations of direction and amplitude parameters occurring simultaneously. The implications of these results for models of eye movement preparation are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of eye and head movements in detecting information about fly balls.

The authors attempted to identify perceptual mechanisms that pick up information for initiating a run to catch fly balls and for judging their landing locations. Fly balls have been shown to be tracked with the eyes and head (R. R. D. Oudejans, C. F. Michaels, F. C. Bakker, & K. Davids, 1999). This raised the question of whether constraining eye and head movements of experienced baseball players by having them wear eye-movement-preventing goggles (eye movements would lead to losing sight of the ball) or a head-movement-preventing neck brace, or both, would limit their capacity (a) to start running in the correct direction and (b) to make correct judgments about the balls' landing locations. Restrictions had minimal effects on response accuracy, but response latency was affected. The goggles increased latency of both running and judging. Moreover, the neck brace decreased judgment time, particularly for difficult balls, suggesting that head stability is important for making judgments. High performance levels suggested that the perceptual system was flexible; that is, different parts of the system can perform the same function. The implications of these findings for perceptual mechanisms are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Photoelectric methods of recording eye movements.

Presents 2 photoelectric methods of recording eye movements to investigate the oculomotor system of hospitalized patients with local brain lesions. The general appearance, operation, and advantages of (a) recording horizontal eye movements with direct ink-writing registration, and (b) simultaneous recording of horizontal and vertical eye movements are described. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adaptive modification of saccadic eye movements.

Experiments are reported in which the target for a saccadic eye movement was displaced during the saccade. Ss adapted to the displacement by altering the amplitudes of subsequent saccades to compensate for it. Analysis of kinematic details of the saccade trajectories revealed that the adaptation did not arise from a simple remapping of perceived target locations. Instead, the adaptation appeared to be accomplished by a change in the gain of the saccadic system. The gain change arose primarily from a change in the magnitude of the force pulse for the saccade, not a change in the duration of the pulse. These results have implications for the mechanisms that underlie saccades in normal situations. In particular, people can separately adjust the magnitudes and durations of the force pulses used to produce saccades. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lexical control of within-word eye movements.

Eye movements were recorded during the reading of long words, which were presented in isolation at their optimal viewing position. Refixations were found to be preferentially directed toward the region of the word that contained the critical letters for distinguishing it from its competitors. In Experiments 1 and 2, low-frequency stimulus words sharing all letters except the initial ones with a high-frequency stimulus word (critical letters at the beginning of the word) elicited more left refixations than low-frequency stimulus words sharing all letters except the final ones with a high-frequency stimulus word (critical letters at the end of the word). A similar result was found in Experiments 3 and 4, using an orthographic priming paradigm. These results suggest that refixations are linked to the selection stage of lexical access, aimed at isolating a single lexical entry among a set of candidates activated during the first fixation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention switching during scene perception: How goals influence the time course of eye movements across advertisements.

Eye movements across advertisements express a temporal pattern of bursts of respectively relatively short and long saccades, and this pattern is systematically influenced by activated scene perception goals. This was revealed by a continuous-time hidden Markov model applied to eye movements of 220 participants exposed to 17 ads under a free-viewing condition, and a scene-learning goal (ad memorization), a scene-evaluation goal (ad appreciation), a target-learning goal (product learning), or a target-evaluation goal (product evaluation). The model reflects how attention switches between two states--local and global--expressed in saccades of shorter and longer amplitude on a spatial grid with 48 cells overlaid on the ads. During the 5- to 6-s duration of self-controlled exposure to ads in the magazine context, attention predominantly started in the local state and ended in the global state, and rapidly switched about 5 times between states. The duration of the local attention state was much longer than the duration of the global state. Goals affected the frequency of switching between attention states and the duration of the local, but not of the global, state. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distractor interference during smooth pursuit eye movements.

When 2 targets for pursuit eye movements move in different directions, the eye velocity follows the vector average (S. G. Lisberger & V. P. Ferrera, 1997). The present study investigates the mechanisms of target selection when observers are instructed to follow a predefined horizontal target and to ignore a moving distractor stimulus. Results show that at 140 ms after distractor onset, horizontal eye velocity is decreased by about 25%. Vertical eye velocity increases or decreases by 1°/s in the direction opposite from the distractor. This deviation varies in size with distractor direction, velocity, and contrast. The effect was present during the initiation and steady-state tracking phase of pursuit but only when the observer had prior information about target motion. Neither vector averaging nor winner-take-all models could predict the response to a moving to-be-ignored distractor during steady-state tracking of a predefined target. The contributions of perceptual mislocalization and spatial attention to the vertical deviation in pursuit are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task effects on eye movements during reading.

The present study examined how proofreading and reading-for-comprehension instructions influence eye movements during reading. Thirty-seven participants silently read sentences containing compound words as target words while their eye movements were being recorded. We manipulated word length and frequency to examine how task instructions influence orthographic versus lexical–semantic processing during reading. Task instructions influenced both temporal and spatial aspects of eye movements: The initial landing position in words was shifted leftward, the saccade length was shorter, first fixation and gaze duration were longer, and refixation probability was higher during proofreading than during reading for comprehension. Moreover, in comparison to instructions for reading for comprehension, proofreading instructions increased both orthographic and lexical–semantic processing. This became apparent in a greater word length and word frequency effect in gaze duration during proofreading than during reading for comprehension. The present study suggests that the allocation of attentional resources during reading is significantly modulated by task demands. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recent studies of eye movements in reading.

Grouping the studies under the general topic headings of techniques of measurement, analysis of the reading process, training to improve eye movements, typography and eye movements, and eye movements and fatigue the author reviews the relevant research literature which has appeared since January, 1945. In general there has been a dimunition of interest in this area. However, there has appeared a large amount of work on visual fixation, speed of eye movements, reaction time of the eye, oculomotor efficiency, and vision during eye movements. There is a need for more basic research. 72-item bibliography. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phonological codes and eye movements in reading.

A number of recent studies using eye movement data have yielded evidence suggesting that phonological codes are activated early in an eye fixation. However, experiments reported by M. Daneman and E. Reingold (1993; M. Daneman, E. M. Reingold, & M. Davidson, 1995) yielded data that led them to argue that phonological codes are primarily activated after lexical access has occurred. In this study, 3 experiments were carried out that were conceptually similar to those of M. Daneman and E. Reingold, and the resulting data supported the position that phonological codes are activated very early in an eye fixation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integrating information across fixations during reading: The use of orthographic bodies and of exterior letters.

Eye movements were recorded to determine whether the parafoveally visible orthographic body of a bisyllabic target word facilitated recognition during the next target fixation. Eye-movement-contingent display changes revealed part of the target, including its orthographic body, or its beginning letters, when it was parafoveally available, but the full target was visible after it was fixated. Target viewing durations showed no benefit from parafoveal preview of orthographic bodies. Instead, preview benefits derived primarily from the preview of word-initial letters. Examination of oculomotor activity revealed that single target fixations were common when the pretarget word received more than one fixation; conversely, more than one target fixation was common when the pretarget word had received a single fixation. Interword fixation strategies thus affected target viewing, but use of parafoveal target previews was unaffected by these strategies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)