The role of visual attention in saccadic eye movements

Trends in Cognitive Sciences, 2000

Scanning of the visual scene is an important selective process in visual perception. In this article we argue that eye-movement data provide an excellent on-line indication of the cognitive processes underlying visual search and reading. We outline some recent advances from physiological investigations of saccadic eye-movement control before focusing on eye-movement behaviour in visual search and reading studies. We consider factors that can affect the duration of fixations and the choice of saccade targets, emphasising continuities between biological and cognitive descriptions. We discuss different ways of measuring cognitive processing time from an eye-movement record and the relationship between attention and eye movements. tel: ϩ44 191 374 2603 fax: ϩ44 191 374 7474 e-mail: s.p.liversedge@ durham.ac.uk, j.m.findlay@durham. ac.uk L i v e r s e d g e a n d F i n d l a y -E y e m o v e m e n t s a n d c o g n i t i o n References a Bergen J.R. and Julesz, B. (1983) Parallel versus serial visual processing in rapid pattern discrimination. Nature 343, 696-698 b Treisman, A. and Gelade, G. (1980) A feature integration theory of attention. Cognit. Psychol. 12, 97-136 c Duncan J. et al. (1994) Direct measurement of attention dwell time in human vision. Nature 369, 313-315 d Sperling G.S. and Weichselgartner, E. (1995) Episodic theory of the dynamics of spatial attention. Psychol. Rev. 102, 503-532 e Theeuwes J. et al. (1998) Our eyes do not always go where we want them to go. Psychol. Sci. 9, 379-385 f Deubel, H. and Schneider, W.X. (1996) Saccade target selection and object recognition: evidence for a common attentional mechanism. Manipulation of stimulus onset delay in reading: evidence for parallel programming of saccades. J. Exp. Psychol. Hum. Percept. Perform. 10, 667-682 i Rayner, K. (1986) Eye movements and the perceptual span in beginning and skilled readers. J. Exp. Child Psychol. 41, 211-236 j Henderson, J.M. and Ferreira, F. (1990) Effects of foveal processing difficulty on the perceptual span in reading: implications for attention and eye movement control. J. Exp. Psychol. Learn. Mem. Cognit. 16, 417-429 k Rayner, K. et al. The effect of clause wrap-up on eye movements during reading. Q. J. Exp. Psychol. (in press) l Reichle, E.D. et al. (1998) Toward a model of eye movement control in reading. Psychol. Rev. 105, 125-157 Box 1. Eye movements and attention 14 Review 1364-6613/00/$ -see front matter

Psychological research, 2004

Two experiments were conducted to examine the relationship between visual attention and saccade programming. Participants had to saccade to a letter string and detect a letter change presented briefly before the saccade onset. Hit probability (i.e., correct detection of a letter change in different positions) was taken as a measure of visual attention focus. The first experiment shows that hit probability depends on the actual landing position. These findings argue for a spatial coupling between saccade programming and the orienting of attention. Also, an unfamiliar letter cluster at the beginning captures attention and prevails over the influence of the saccade in preparation. Experiment 2, in which the letter change occurred at different times during the saccade latency, shows that attention shifts and focuses on the saccade target at the expense of the other parts of the stimulus when the motor program is ready to be executed. The theoretical implications of these results are discussed.

Acta Psychologica, 1995

Saccadic eye movements are made at least 100,000 times each day. It is wel1 known that sensitivity to visual input is suppressed during saccades; recent evidente suggests that some kinds of information processing are suppressed as well. Suppression during saccades implies that processing occurs discretely (during eye fixations only), rather than continuously (during both fixations and saccades). We examined this issue in the context of the Posner and Snyder (1975) primed letter-matching task. We found that a prime viewed in one fixation had a larger influence on targets viewed in a second fixation when a long rather than a short saccade separated the two fixations. This result demonstrates that at least some information processing occurs during saccades. Tel.: + 1 217 333-7746.

Laboratory tasks used to study vision and attention usually require steady fixation, while natural visual processing occurs during the brief pauses between successive saccades. We studied vision and attentional allocation during intersaccadic pauses as subjects made repetitive sequences of saccades. Displays contained six outline squares located along the perimeter of an imaginary circle (diam 4°). Saccades were made in sequence to every other square. The visual task was to identify the orientation (2AFC) of a Gabor test stimulus that appeared briefly (91 ms) along with superimposed noise in one of the squares during a randomly selected intersaccadic pause. Gabor location was cued in advance and noise frames were presented in all squares. Contrast thresholds during intersaccadic pauses were as much as 2-3 times higher than during steady fixation with comparable cueing. Thresholds improved over time during the intersaccadic pause, and the lowest extrafoveal thresholds (statistically indistinguishable from those at the same locations during steady fixation) were found for the location that was to be the target of the next saccade in the sequence. These results show that vision during intersaccadic pauses varies over space and time due to changes in the distribution of attention, as well as to visual suppression that may be related to the execution of the saccades themselves. Generation of sequences of accurate saccades encouraged a strategy of attentional allocation in which resources were dedicated primarily to the goal of the next saccade, leaving little attention for processing objects at other locations.

Experimental Brain Research, 2008

2012

Jonikaitis D, Szinte M, Rolfs M, Cavanagh P. Allocation of attention across saccades. ever the eyes move, spatial attention must keep track of the locations of targets as they shift on the retina. This study investigated transsaccadic updating of visual attention to cued targets. While observers prepared a saccade, we flashed an irrelevant, but salient, color cue in their visual periphery and measured the allocation of spatial attention before and after the saccade using a tilt discrimination task. We found that just before the saccade, attention was allocated to the cue's future retinal location, its predictively "remapped" location. Attention was sustained at the cue's location in the world across the saccade, despite the change of retinal position whereas it decayed quickly at the retinal location of the cue, after the eye landed. By extinguishing the color cue across the saccade, we further demonstrate that the visual system relies only on predictive allocation of spatial attention, as the presence of the cue after the saccade did not substantially affect attentional allocation. These behavioral results support and extend physiological evidence showing predictive activation of visual neurons when an attended stimulus will fall in their receptive field after a saccade. Our results show that tracking of spatial locations across saccades is a plausible consequence of physiological remapping.

Saccadic latency is reduced by a temporal gap between fixation point and target, by identification of a target feature, and by movement in a new direction (inhibition of saccadic return, ISR). A simple additive model was compared with a shared resources model that predicts a three-way interaction. Twenty naive participants made horizontal saccades to targets left and right of fixation in a randomised block design. There was a significant three-way interaction among the factors on saccade latency. This was revealed in a two-way interaction between feature identification and the gap versus no gap factor which was only apparent when the saccade was in the same direction as the previous saccade. No interaction was apparent when the saccade was in the opposite direction. This result supports an attentional inhibitory effect that is present during ISR to a previous location which is only partly released by the facilitative effect of feature identification and gap. Together, anticipatory error data and saccade latency interactions suggest a source of ISR at a higher level of attention, possibly localised in the dorsolateral prefrontal cortex and involving tonic activation.

Vision Research, 1995

Accurate saccadic programming in natural visual scenes requires a signal designating which of the many potential targets is to be the goal of the saccade. Is this signal controlled by the allocation of perceptual attention, or do saccades have their own independent selective filter? We ...

Радиоэлектроника, наносистемы, информационные технологии, 2020

The work is devoted to the peculiarities of gaze movement in fixations and saccades when reading text and perceiving neutral images. The existence of multiple (almost unidirectional) displacements in fixations was discovered, the probability of which significantly exceeds the similar probability in simulated random fixations. The dependence of the correlation of time spent in fixations on the degree of distortion of texts when reading them was investigated. An interesting aspect of research is the statistics of the distribution of the direction of gaze shifts in fixations and saccades. It is shown that during reading the direction of displacements in saccades is predetermined. In the case of fixations in the distribution, vertical and horizontal directions are distinguished, and this is typical not only when reading a text, but also when perceiving various images, including those rotated at different angles. The individual characteristics of the visual system associated with the non-synchronous movement of the gaze of the left and right eyes in some subjects were found. It was determined the noise error of the eye-tracking recording system when registering the gaze displacements. It is shown that down to gaze displacements of the order of 1 mm, the noises of the registering measurement system prevails, which have a normal distribution along the length, and are uniformly distributed over the angle.

Journal of Cognitive Neuroscience, 1996

Two experiments examined saccadic reaction time (RT) in response to visual targets as a function of fixation offset condition (no offset; target simultaneous with offset and 200-msec offset-target SOA) in prosaccade and antisaccade tasks. The second experiment also included a condition in which saccades were made in response to verbal commands presented auditorally. To ensure that observers were equally prepared in each condition, auditory warning tones preceded target onset on every trial. The RT reduction associated with fixation offset (FOE, or gap effect) was identical with visual targets in the prosaccade task and in response to verbal signals, strongly implicating motor, rather than sensory, mechanisms in the FOE. The FOE in the antisaccade task was significant, but it was also significantly smaller than in the other tasks. We speculate that the reduced FOE in the antisaccade task may be due to the requirement to inhibit the superior colliculus when the target directed saccadi...