Eye Movement Indices Research Articles

Eye movement in isolated spelling disorder – An analysis using the dual route model of visual word recognition

Abstract The aim of the study is to investigate whether adolescents with isolated spelling disorder face difficulties connected with the functional effectiveness of words' orthographic representations in the mental lexicon, and to determine the nature of such dysfunction. The assumed effectiveness indicator for the function of orthographic representations was the characteristics of eye movements performed in course of assessing the correctness of spelling of words. The main group effect was not found in the eye movement indices. The different patterns of eye movement between poor and good spellers were found in the context of the recognition accuracy and correctness of notation. This indicates that spelling disorder is not a problem of perception and visual attention, nor is it a problem of phonology (proper function of sub-lexical and lexical route). We suggest it could be a symptom of difficulties in coding and perceptual categorization.

Using Eye Movements as an Index of Implicit Face Recognition in Autism Spectrum Disorder

Individuals with an autism spectrum disorder (ASD) typically show impairment on face recognition tasks. Performance has usually been assessed using overt, explicit recognition tasks. Here, a complementary method involving eye tracking was used to examine implicit face recognition in participants with ASD and in an intelligence quotient-matched non-ASD control group. Differences in eye movement indices between target and foil faces were used as an indicator of implicit face recognition. Explicit face recognition was assessed using old-new discrimination and reaction time measures. Stimuli were faces of studied (target) or unfamiliar (foil) persons. Target images at test were either identical to the images presented at study or altered by changing the lighting, pose, or by masking with visual noise. Participants with ASD performed worse than controls on the explicit recognition task. Eye movement-based measures, however, indicated that implicit recognition may not be affected to the same degree as explicit recognition. Autism Res 2012, 5: 363-379. © 2012 International Society for Autism Research, Wiley Periodicals, Inc.

Aerobic fitness enhances relational memory in preadolescent children: The FITKids randomized control trial

It is widely accepted that aerobic exercise enhances hippocampal plasticity. Often, this plasticity co-occurs with gains in hippocampal-dependent memory. Cross-sectional work investigating this relationship in preadolescent children has found behavioral differences in higher versus lower aerobically fit participants for tasks measuring relational memory, which is known to be critically tied to hippocampal structure and function. The present study tested whether similar differences would arise in a clinical intervention setting where a group of preadolescent children were randomly assigned to a 9-month after school aerobic exercise intervention versus a wait-list control group. Performance measures included eye-movements as a measure of memory, based on recent work linking eye-movement indices of relational memory to the hippocampus. Results indicated that only children in the intervention increased their aerobic fitness. Compared to the control group, those who entered the aerobic exercise program displayed eye-movement patterns indicative of superior memory for face-scene relations, with no differences observed in memory for individual faces. The results of this intervention study provide clear support for the proposed linkage among the hippocampus, relational memory, and aerobic fitness, as well as illustrating the sensitivity of eye-movement measures as a means of assessing memory.

Here’s Looking at You

This study represents the beginning of a systematic effort to utilize eye-movement responses in order to better understand individuals’ processing strategies during the Rorschach Inkblot Method (RIM). Eye movements reflect moment-by-moment spatial and temporal processing of visual information and represent a useful approach for studying the RIM with potential clinical implications. Thirteen participants responded to the Rorschach while eye movements were being monitored. Several eye-movement indices were studied which reflect different aspects of information processing. Differences among the Rorschach cards were found for several eye-movement indices. For example, fixation durations were longer during a second viewing of the cards than during the first. This is consonant with an attempt to acquire conceptually difficult information, as participants were reinterpreting the cards. Results are discussed in terms of visual information processing strategies during the RIM and the potential usefulness of eye movements as a response measure to the RIM.

Distinguishing highly confident accurate and inaccurate memory: Insights about relevant and irrelevant influences on memory confidence

It is generally believed that accuracy and confidence in one's memory are related, but there are many instances when they diverge. Accordingly it is important to disentangle the factors that contribute to memory accuracy and confidence, especially those factors that contribute to confidence, but not accuracy. We used eye movements to separately measure fluent cue processing, the target recognition experience, and relative evidence assessment on recognition confidence and accuracy. Eye movements were monitored during a face–scene associative recognition task, in which participants first saw a scene cue, followed by a forced-choice recognition test for the associated face, with confidence ratings. Eye movement indices of the target recognition experience were largely indicative of accuracy, and showed a relationship to confidence for accurate decisions. In contrast, eye movements during the scene cue raised the possibility that more fluent cue processing was related to higher confidence for both accurate and inaccurate recognition decisions. In a second experiment we manipulated cue familiarity, and therefore cue fluency. Participants showed higher confidence for cue–target associations for when the cue was more familiar, especially for incorrect responses. These results suggest that over-reliance on cue familiarity and under-reliance on the target recognition experience may lead to erroneous confidence.

Comparison of Expert and Novice Eye Movement Behaviors during Landing Flight

Objective To study expert and novice eye movement pattern during simulated landing flight for providing references to evaluate flight performance and training of pilots. Methods The subjects were divided in to two group s of expert and novice according to their flight simulation experience. Eye movement data were recorded when they were performing landing task. Comparison of expert and novice flight performance data and eye movement data was made. Results It was found that the differences between expert and novice lay not only in flight performance but also in eye movement pattern. Performance of expert was better than novice. Expert had shorter fixation time, more fixation points, faster scan velocity, greater scan frequency and wider scan area than novice. It was also found that eye movement pattern of expert bring lower mental workload than novice. Conclusion Flight performance is related to eye movement pattern. Effective eye movement pattern is related to good flight performance. The analysis of eye movement indices can evaluate pilots’ flight performance and provide reference for flight training.

Towards a driver fatigue test based on the saccadic main sequence: A partial validation by subjective report data

Developing a valid measurement of mental fatigue remains a big challenge and would be beneficial for various application areas, such as the improvement of road traffic safety. In the present study we examined influences of mental fatigue on the dynamics of saccadic eye movements. Based on previous findings, we propose that among amplitude and duration of saccades, the peak velocity of saccadic eye movements is particularly sensitive to changes in mental fatigue. Ten participants completed a fixation task before and after 2 h of driving in a virtual simulation environment as well as after a rest break of fifteen minutes. Driving and rest break were assumed to directly influence the level of mental fatigue and were evaluated using subjective ratings and eye movement indices. According to the subjective ratings, mental fatigue was highest after driving but decreased after the rest break. The peak velocity of saccadic eye movements decreased after driving while the duration of saccades increased, but no effects of the rest break were observed in the saccade parameters. We conclude that saccadic eye movement parameters—particularly the peak velocity—are sensitive indicators for mental fatigue. According to these findings, the peak velocity analysis represents a valid on-line measure for the detection of mental fatigue, providing the basis for the development of new vigilance screening tools to prevent accidents in several application domains.

Eye movements characteristics of Chinese dyslexic children in picture searching

Reading Chinese, a kind of ideogram, relies more on visual cognition. The visuospatial cognitive deficit of Chinese dyslexia is an interesting topic that has received much attention. The purpose of current research was to explore the visuopatial cognitive characteristics of Chinese dyslexic children by studying their eye movements via a picture searching test. According to the diagnostic criteria defined by ICD-10, twenty-eight dyslexic children (mean age (10.12 +/- 1.42) years) were enrolled from the Clinic of Children Behavioral Disorder in the third affiliated hospital of Sun Yat-sen University. And 28 normally reading children (mean age (10.06 +/- 1.29) years), 1:1 matched by age, sex, grade and family condition were chosen from an elementary school in Guangzhou as a control group. Four groups of pictures (cock, accident, canyon, meditate) from Picture Vocabulary Test were chosen as eye movement experiment targets. All the subjects carried out the picture searching task and their eye movement data were recorded by an Eyelink II High-Speed Eye Tracker. The duration time, average fixation duration, average saccade amplitude, fixation counts and saccade counts were compared between the two groups of children. The dyslexic children had longer total fixation duration and average fixation duration (F = 7.711, P < 0.01; F = 4.520, P < 0.05), more fixation counts and saccade counts (F = 7.498, P < 0.01; F = 11.040, P < 0.01), and a smaller average saccade amplitude (F = 29.743, P < 0.01) compared with controls. But their performance in the picture vocabulary test was the same as those of the control group. The eye movement indexes were affected by the difficulty of the pictures and words, all eye movement indexes, except saccade amplitude, had a significant difference within groups (P < 0.05). Chinese dyslexic children have abnormal eye movements in picture searching, applying slow fixations, more fixations and small and frequent saccades. Their abnormal eye movement mode reflects the poor ability and strategy of visual information processing.

Validity of Eye Movement Methods and Indices for Capturing Semantic (Associative) Priming Effects

The purpose of this investigation was to evaluate the usefulness of eye movement methods and indices as a tool for studying priming effects by verifying whether eye movement indices capture semantic (associative) priming effects in a visual cross-format (written word to semantically related picture) priming paradigm. In the stimuli development phase, words semantically associated to an array of pictures were generated based on 100 adults' association data for each picture. A total of 40 additional adult participants with normal language engaged in an eye movement experiment using the word-picture associations developed previously. The design consisted of each prime preceding a display showing 1 high-association (target) and 2 low-association (nontarget) images. Fixation durations, locations, and latencies were measured. Images semantically related to the prime showed greater fixation durations and shorter latencies compared to nontargets. Eye movement and traditional reaction time measures were found to correlate for some of the experimental conditions. Results showed that free-viewing eye movement measures, in which participants are not instructed to look at anything in particular, hold promise as valid indicators of priming effects. Further research in this area will help to advance language-processing theories in individuals with and without language impairment.

An evaluation of multiple‐choice test images for comprehension assessment in aphasia

Background: Using images in multiple‐choice formats for comprehension testing in aphasia is common. It is generally assumed that persons being assessed perceive the content of the images represented in such tasks. However, specific visual characteristics of individual images may influence visual attention, which may influence accuracy in the selection of a correct target image corresponding to a verbal stimulus. The validity of test responses may be confounded by (1) physical stimulus features, such as size, and (2) semantic content conveyed by images, such as image familiarity. This study is supported by a grant (# DC 0015301 A1) from the National Institute on Deafness and other Communication Disorders of the National Institutes of Health. We thank Natalie Douglas for her important contributions, Yoon‐Soo Lee for creation and editing of visual stimuli, and Sonny Kim for statistical consultation. Aims: The first aim was to develop a rating instrument to assess visual stimulus properties and semantic content conveyance in multiple‐choice images, based on an extensive review of empirical literature and validated by experts in graphic design. The second aim was to study the degree of relationship between viewers' subjective ratings of images selected from published aphasia batteries, using the rating instrument, and eye movement measures recorded as independent viewers looked at the same images. The third aim was to compare the viewers' actual eye movement indices of disproportionate visual attention to an ideal value of evenly proportionate visual attention for each image set. Methods & Procedures: A rating instrument, based on an extensive review of literature and assessed and revised by graphic design and eye‐tracking experts, was developed to identify such influences within multiple‐choice images and was assessed through empirical testing of viewers' eye movement patterns as they looked at images from published aphasia tests. A total of 20 adults rated 20 image sets from five aphasia batteries. Eye movements were recorded for a separate group of 40 adults viewing the same images. Outcomes & Results: Ratings were not statistically correlated with eye movement responses. All multiple‐choice image sets prompted significantly disproportionate visual attention. Conclusions: Results highlight the importance of: (1) considering the possible influence of visual stimulus confounds on any given patient's test performance, and (2) better controlled image design for multiple‐choice test images to improve the validity of assessment. Further research is needed to improve subjective and objective means of assessment of images and guidelines for improved design of multiple‐choice image displays.

Evidence for a global scanpath strategy in viewing abstract compared with realistic images

Scanpaths, the repetitive sequences of saccadic eye movements, occurred when subjects viewed slide projections of both realistic and abstract art. Variance analysis demonstrated that global/local eye movement indices were lower for local scanning by professional art viewers who relied on more global viewing, particularly in abstract images. Non-professional, unsophisticated subjects carried their local scanpath patterns from realistic images on to abstract images. The blink rate of professional subjects viewing abstract images was also significantly lower, indicating increased visual effort. Non-professional viewers showed no difference in blink rates.

Consistency of the first fixation when viewing a standard geometric stimulus

Eye movements in response to presentation of a standard geometric figure (Rey Complex Geometric Figure) were investigated in 33 normal subjects. The figure was presented to each subject for 20 s, with instructions to remember as much detail as possible. Stimulus display was managed by special software that ensured all subjects were focused on the centre of the monitor before presentation, thus controlling for the initial point of gaze. Subjects were instructed, after viewing the stimulus, to reproduce the figure to scale on a blank sheet of paper. Location of the first voluntary fixation during the viewing period was consistently near the same feature in 80% of subjects (cohort I, n = 20). Patterns of eye movement during the remainder of the period, however, were found to vary widely among individuals. A complementary experiment using a second group of subjects (cohort II, n = 13) was undertaken to examine possible effects of brain function lateralisation on processing a feature in the left hemi-field. No lateralisation effect was evident and consistent identification of the same feature in the first voluntary fixation was confirmed for all subjects. No systematic relationships were found between eye movement indices obtained from real-time viewing of the Rey Figure and subsequent recall by drawing.

An Eye-Movement Analysis of the Effects of Scotopic Sensitivity Correction on Parsing and Comprehension

Does scotopic sensitivity correction enhance parsing and, thus, comprehension? Twenty-two readers with scotopic sensitivity (mean age = 20.3 yrs.; 40.9% male) parsed sentences under scotopic correction and control conditions. Measures included eye-movement indices of parsing and comprehension questions. Although eye movements suggested enhanced parsing, comprehension scores were not significantly improved with correction.

Eye movement and pupillary response indices of mental workload during visual search of symbolic displays

Eye movement and pupillary response measures (in addition to search time and accuracy) were collected as indices of visual workload during two experiments designed to evaluate the addition of colour coding to a symbolic tactical display. Displays also varied with regard to symbol density and the type of information participants were required to abstract from the display. These variables were factorially manipulated to examine the effects of colour coding in conditions of varying difficulty. In Experiment 1 ( n = 8), search time and the number of eye fixations were affected by all variables and in a similar manner; fixation dwell time and the pupillary response dissociated from the other measures. Compared to monochrome displays, colour coding facilitated search (reduced search time, but not accuracy) during exhaustive search, but had no effect during self-terminating search. Experiment 2 ( n = 8) was a replication of Experiment 1 with a pseudo-search control condition added to examine further the pupillary response measures: in particular, to assess the effects of the physical parameters of the displays, and to verify the findings of Experiment 1. Pupillary response measures were sensitive to the information processing demands of the search task, not merely to the physical parameters of the display. Further, the search time, accuracy, and eye movement results from the active search condition generally replicated Experiment 1, but the fixation dwell time data did not. These between-study differences were interpreted as indicating the importance of participant search strategy.

Eye movement indices of mental workload

Four investigations were carried out to assess the feasibility of using eye movement measures as indices of mental workload. In the first experiment, saccadic extent was measured during free viewing while subjects performed low, moderate and high complexity, auditory tone counting as the workload tasks. The range of saccadis extent decreased significantly as tone counting complexity (workload) was increased. In the second experiment the range of spontaneous saccades was measured under three levels of counting complexity with a visual task that did not require fixation or tracking. The results indicated that the extent of saccadic eye movements was significantly restricted as counting complexity increased. In the third experiment, the effects of practice were examined and decreased saccadic range under high tone counting complexity was observed even when significant increases in performance occured with practice. Finally, in experiment 4, the first experiment was repeated with additional optokinetic stimulation and the saccadic range was again observed to decrease with tone counting complexity. The results indicated that the extent of spontaneous and elicited eye movements was significantly restricted as counting complexity increased. We conclude that this measure may provide a valuable index of mental workload.

Psychophysiological Correlates of the Spontaneous K-Complex

A pilot study covering three nights and two studies were carried out to investigate the psychophysiological correlates of the spontaneous K-complex in relation to intense psychotherapy. The pilot study produced evidence that the K-complex was not consistent and stable within or across nights and that its variability might be sensitive to psycho-emotional influences. In the first major study 2 subjects were recorded non-consecutively over a 3-wk. period during experience of intensive therapy while in the second 6 subjects were studied before and after two therapeutic sessions. Results indicated that nights after therapy differed significantly from baseline nights and a significant interaction took place between subjects and therapy on one or more variables of the K-complex and several eye movement indices. Some relationship to length of time in therapy was also noted. These findings were interpreted to indicate a possible relationship between complete expression of feeling and the occurrence of phasic events in the sleeping EEG.

Eye movement indices of cognitive behavior

Some of the earlier studies of eye movements were conducted with expansive expectations, which recent work has not substantiated. However, line of sight recordings of eye movements do appear to have potential for both research and practice in audiovisual communication. This paper will report recent studies which employed eye movement data in the study of cognitive behavior. The following four categories will provide a framework for this discussion: perception, associative learning, search behavior, and problem solving. The significance of eye movements (hereafter referred to as EM) may be better understood if there is a brief digression to consider certain characteristics of the eye. The usual analogy between eye and camera is quite inaccurate, but with several modifications it may suffice for present purposes. Imagine a camera mounted on a free-head tripod so that it can be directed at will up and down, side to side. Let the film be both