Showing papers on "Eye tracking published in 1984"

Integrating pictorial information across eye movements.

Abstract: Six experiments are reported dealing with the types of information integrated across eye movements in picture perception. A line drawing of an object was presented in peripheral vision, and subjects made an eye movement to it. During the saccade, the initially presented picture was replaced by another picture that the subject was instructed to name as quickly as possible. The relation between the stimulus on the first fixation and the stimulus on the second fixation was varied. Across the six experiments, there was about 100-130 ms facilitation when the pictures were identical compared with a control condition in which only the target location was specified on the first fixation. This finding clearly implies that information about the first picture facilitated naming the second picture. Changing the size of the picture from one fixation to the next had little effect on naming time. This result is consistent with work on reading and low-level visual processes in indicating that pictorial information is not integrated in a point-by-point manner in an integrated visual buffer. Moreover, only about 50 ms of the facilitation for identical pictures could be attributed to the pictures having the same name. When the pictures represented the same concept (e.g., two different pictures of a horse), there was a 90-ms facilitation effect that could have been the result of either the visual or conceptual similarity of the pictures. However, when the pictures had different names, only visual similarity produced facilitation. Moreover, when the pictures had different names, there appeared to be inhibition from the competing names. The results of all six experiments are consistent with a model in which the activation of both the visual features and the name of the picture seen on the first fixation survive the saccade and combine with the information extracted on the second fixation to produce identification and naming of the second picture.

Pursuit eye movement dysfunctions in schizophrenia. Family evidence for specificity.

Abstract: • In a number of previous investigations, eye tracking dysfunctions had been reliably found in from 50% to 85% of schizophrenic patients, about 40% of manic-depressive patients, and about 8% of the normal population. We report similar smooth pursuit eye movement dysfunctions in 34% of the parents (or 55% of parental pairs) of schizophrenic patients compared with 10% of the parents (or 17% of parental pairs) of manic-depressive patients. Parental eye movement dysfunctions are significantly related to the diagnosis of the patient and not to the patient's eye tracking performance. These data suggest that, in the absence of other CNS disease, these eye tracking dysfunctions represent familial markers of vulnerability to schizophrenia.

Neural control of vergence eye movements: activity of abducens and oculomotor neurons

Abstract: Single

Small Saccades to Double-Stepped Targets Moving in Two Dimensions

Abstract: We studied saccadic eye tracking, concentrating particularly on the situation where a target makes a jump movement in the period whilst a saccade is being prepared to a previous jump. Such a perturbation affects the saccadic system in several ways. The spatial characteristics of the movement, amplitude or direction equally, can be modified on the basis of new information arriving up to 80 msec before the initiation of the saccade. The perturbation rarely produces any substantial effects on the trajectory of the movement itself, but the occasional exceptions reveal the presence of a goal seeking feedback mechanism underlying saccadic production.

Impaired Smooth Pursuit Eye Movement: Vulnerability Marker for Schizotypal Personality Disorder in a Normal Volunteer Population

Abstract: Impaired smooth pursuit eye movement has been proposed as a possible biologic marker for schizophrenia. Preliminary studies have suggested that this impairment may be associated with social introversion and related psychopathology in a nonpsychiatric population. To evaluate the relationship between dysfunctional smooth pursuit eye movement and schizophrenia-related psychopathology, the authors screened a new, volunteer sample of 284 male college students for eye tracking accuracy. Volunteers identified as low-accuracy trackers were significantly more likely to be diagnosed (blindly) as having a schizotypal personality disorder by DSM-III criteria than those identified as high-accuracy trackers. The authors suggest that disordered smooth pursuit eye movement may reflect a vulnerability marker for schizotypal personality disorder.

Operational Problems in Analysing Eye Movements

Abstract: Eye movement measurement with cornea-pupil reflection technique requires an operational definition of a fixation to be able to analyse eye movements by data reduction strategies. The present paper illustrates some effects of variable fixation definitions on the calculation of eye movement characteristics conducting an experiment with simple visual scanning tasks. The results of eye movement evaluation are dependent on the defined size of a fixation. They are varying in alternation with stimulus aspects provoking different densities of fixation locations as well as with individual eye movement behavior.

Computerized video tasks as training techniques for driving-related perceptual deficits of persons with brain damage: a pilot evaluation

Abstract: This pilot study investigated the modifiability of perceptual deficits by training which consisted of performing microcomputer-generated video tasks These commercially available remedial programs tapped a range of skills, such as right/left discrimination, color matching, visual scanning, judgment of line orientation, visual search, shape discrimination, visual memory, eye tracking, visuomotor coordination, and visual imagery Four subjects with acquired brain damage were given 10 hours of training Perceptual skills were assessed with a battery of seven paper-and-pencil tests administered both before and after the training Following the training two subjects showed some improvement on several of the perceptual tests used, while two other subjects showed improvement on only a limited number of tests Based on these results and on the performance changes on the video tasks themselves, a comprehensive evaluation of the potential benefits of this type of training on driving performance is recommended

Functional between-hand differences and outflow eye position information

Abstract: Pointing accuracy with an unseen hand to a just-extinguished visual target was examined in various eye movement conditions. When subjects caught the target by a saccade, they showed about the same ...

Smooth pursuit eye movements in normal and dyslexic children

Abstract: This paper describes a detailed study of horizontal eye movements associated with visual tracking of a smoothly moving target. Essentially all children, even at target velocities as low as 5°/sec., show some saccadic eye movements superimposed on smooth tracking movements. Detailed analysis of pursuit eye-movements from a group of 26 poor readers and 34 normal controls (8 to 13 yr.) showed that about 25% of poor readers have an abnormally raised saccadic component in smooth pursuit. This suggests that studies of eye movements during tracking of smoothly moving targets at low velocity, combined with a quantitative approach to data analysis, may be useful for early detection of a significant proportion of poor-reading children.

Use of the image‐retina and eye‐head movement visual systems during coincidence‐anticipation performance

Abstract: Movement is visually detected by one of two systems: (a) the image‐retina system (image moves along stationary retina), or (b) the eye‐head movement system (eye moves to keep image stationary on retina). Previous research has shown that subjects, when they have to respond to movement to execute a coincidence‐anticipation task, will choose the image‐retina system or the eye‐head system, but it has failed to establish the superiority of either system. The present study was designed to examine this issue. Young adults (n = 28) of both sexes performed two series of 12 coincidence‐anticipation trials each. Three stimulus speeds were administered in a randomized order, standardized across subjects. Eye movements were recorded with the head stabilized. In one series, subjects were instructed to follow the stimulus with their eyes. In the other, they were told to fix on the target point and watch the stimulus in their peripheral vision. Half of the subjects initiated testing in each condition. Time error...

Eye Movement Control During Reading: The Effect of Word Units

Abstract: In recent years psychologists have shown a renewed interest in eye movement in reading (see reviews by Levy-Schoen & O’Regan, 1979; McConkie, 1983; Rayner, 1978a) This work has been motivated by more than a simple curiosity about the nature of eye movement control Rather, eye movement data are regarded as having the potential for testing theories about the ongoing perceptual and language processing taking place during reading As people read, a great deal of variability is exhibited in how far they move their eyes and in how long their eyes remain centered on different locations in the text There is general faith in, and some evidence for, the notion that this variability reflects differences in the nature of the perceptual and cognitive processes occurring at different locations in the text It is assumed that if we could discover the ways in which mental processes influence eye movement behavior, then we would be able to use eye movement records to infer the nature of the processing occurring at different places in the text In effect, the eye movement pattern would then become a language by which the brain communicates some of its activities to the psychologist The hope that this can be achieved is a strong motivator for research on eye movement control in reading (Just & Carpenter, 1980; McConkie, Hogaboam, Wolverton, Zola, & Lucas, 1979)

Saccadic Eye Movements and Visual Stability: Preliminary Considerations Towards a Cognitive Approach

Abstract: The images of the objects projected on the retina move with every saccade. Yet, we perceive these objects as stationary, i.e., we neither perceive the objects as moving during the saccade (dynamic component) nor do we perceive them as displaced as a result of the saccade (static component). This is the phenomenon of visual stability, which has been extensively studied since Helmholtz’ (1866) early work (for overviews see Dolezal, 1982; Festinger & Cannon, 1965; Gyr, 1972; MacKay, 1973; Matin, L., 1972,1982;McClosky, 1981;Shebilske, 1977).

Eye movements, performance and visual comfort using VDTs

Abstract: Two experiments are reported in which the mean luminance and the luminance contrast of pseudo texts displayed on a VDT were varied. The subjects carried out a lettersearch task and rated the visual comfort of the texts . The eye movements of the subjects were also recorded. The results show a good correspondence between visual comfort, which is a subjective attribute, and object ive parameters related to eye movements and performance. It may be found that the scaling of visual comfort is not only an economical but also a valid way to evaluate VDT displays.

Eye movement analysis: Reading and moving target pursuit

Abstract: The design and application of an extensive and general software-based system for the study and analysis of eye movements in human subjects is described. The system can find application in a number of specialties in medicine, particularly clinical neurophysiology, as well as in studies of eye movement dynamics, including reading dynamics, in dyslexia. It is designed to run on the PDP 11 family of computers with standard peripherals and operating under the RT 11 executive.

Real Time Pattern Recognition And Feature Analysis From Video Signals Applied To Eye Movement And Pupillary Reflex Monitoring

Abstract: Original techniques for real time pattern recognition and feature analysis from standard video signals have been applied to the monitoring of eye movements and pupillary size during visual field examinations in routine ophthalmological practice.

Artificial eye for assessing corneal-reflection eye trackers

Abstract: An artificial eye for assessing corneal-reflection eye trackers is described. The “eye” simulates an adult human eye and consists of a contact lens of the same curvature as the cornea.

Processing TV Information and Eye Movements Research

Abstract: The purpose of our contribution was to make an inventory of the trade-offs between looking at the moving image and processing the subtitle. Does reading occur? Is there successive scanning from the pictures to the subtitles and from the subtitles back to the pictures? Could both forms of information be processed simultaneously with no loss of understanding of the flow of information in the moving image? What information is captured in peripheral and parafoveal vision, and how is it used in the purposive sequence of eye movements?

Eye Movement Control during Reading: The Effect of Word Units. Technical Report No. 310.

Abstract: In recent years psychologists have shown a renewed interest in eye movement in reading (see reviews by Levy-Schoen & O’Regan, 1979; McConkie, 1983; Rayner, 1978a). This work has been motivated by more than a simple curiosity about the nature of eye movement control. Rather, eye movement data are regarded as having the potential for testing theories about the ongoing perceptual and language processing taking place during reading. As people read, a great deal of variability is exhibited in how far they move their eyes and in how long their eyes remain centered on different locations in the text. There is general faith in, and some evidence for, the notion that this variability reflects differences in the nature of the perceptual and cognitive processes occurring at different locations in the text. It is assumed that if we could discover the ways in which mental processes influence eye movement behavior, then we would be able to use eye movement records to infer the nature of the processing occurring at different places in the text. In effect, the eye movement pattern would then become a language by which the brain communicates some of its activities to the psychologist. The hope that this can be achieved is a strong motivator for research on eye movement control in reading (Just & Carpenter, 1980; McConkie, Hogaboam, Wolverton, Zola, & Lucas, 1979).

How Saccadic Eye Movements Find their Target

Abstract: Normally, we perform saccadic eye movements continuously to explore our visual environment, selecting objects in the visual field in order to redirect our gaze. The target once selected, the oculomotor system has to compute its retinal eccentricity to determine the amplitude of the goal-directed saccade. After the saccade, the oculomotor system has to check the result of the movement and, eventually, a correction must be performed. We investigated how visual information is processed to compute saccadic amplitudes and to correct motor errors.