Expertise in pictorial perception: eye-movement patterns and visual memory in artists and laymen

In two sessions with free scanning and memory instructions, eye-movement patterns from nine artists were compared with those of nine artistically untrained participants viewing 16 pictures representing a selection of categories from ordinary scenes to abstraction: 12 pictures were made to accommodate an object-oriented viewing mode (selection of recognisable objects), and a pictorial viewing mode (selection of more structural features), and 4 were abstract. The artistically untrained participants showed preference for viewing human features and objects, while the artists spent more scanning time on structural/abstract features. A group by session interaction showed a change of viewing strategy in the artists, who viewed more objects and human features in the memory task session. A verbal test of recall memory showed no overall difference in the number of pictures remembered, but the number of correctly remembered pictorial features was significantly higher for artists than for the artistically untrained viewers, irrespective of picture type. No differences in fixation frequencies/durations were found between groups across sessions, but a significant task-dependent-group by session interaction of fixation frequency/duration showed that the artistically untrained participants demonstrated repetition effects in fewer, longer fixations with repeated viewing, while the opposite pattern obtained for the artists.     

Differences in eye-movement patterns between anorexic and control observers when judging body size and attractiveness

Attentional biases may influence the eye-movements made when judging bodies and so alter the visual information sampled when making a judgment. This may lead to an overestimation of body size. We measured the eye-movements made by 16 anorexic observers and 16 age-matched controls when judging body size and attractiveness. We combined behavioural data with a novel eye-movement analysis technique that allowed us to apply spatial statistical techniques to make fine spatial discriminations in the pattern of eye-movements between our observer groups. Our behavioural results show that anorexic observers overestimate body size relative to controls and find bodies with lower body mass indexes more attractive. For both judgments, the controls' fixations centre on the stomach, but the anorexic observers show a much wider fixation pattern extending to encompass additional features such as the prominence of the hip and collar bones. This additional visual information may serve to alter their behavioural judgments towards an overestimation of body size and shift their ideal body size towards a significantly lower value.     

Development of eye-movement control

Cognitive control of behavior continues to improve through adolescence in parallel with important brain maturational processes including synaptic pruning and myelination, which allow for efficient neuronal computations and the functional integration of widely distributed circuitries supporting top-down control of behavior. This is also a time when psychiatric disorders, such as schizophrenia and mood disorders, emerge reflecting a particularly vulnerability to impairments in development during adolescence. Oculomotor studies provide a unique neuroscientific approach to make precise associations between cognitive control and brain circuitry during development that can inform us of impaired systems in psychopathology. In this review, we first describe the development of pursuit, fixation, and visually-guided saccadic eye movements, which collectively indicate early maturation of basic sensorimotor processes supporting reflexive, exogenously-driven eye movements. We then describe the literature on the development of the cognitive control of eye movements as reflected in the ability to inhibit a prepotent eye movement in the antisaccade task, as well as making an eye movement guided by on-line spatial information in working memory in the oculomotor delayed response task. Results indicate that the ability to make eye movements in a voluntary fashion driven by endogenous plans shows a protracted development into adolescence. Characterizing the transition through adolescence to adult-level cognitive control of behavior can inform models aimed at understanding the neurodevelopmental basis of psychiatric disorders.     

Fixation disengagement and eye-movement latency

We examined eye-movement latencies to a target that appeared during visual fixation of a stationary stimulus, a moving stimulus, or an extrafoveal stimulus. The stimulus at fixation was turned off either before target onset (gap condition) or after target onset (overlap condition). Consistent with previous research, saccadic latencies were shorter in gap conditions than they were in overlap conditions (the gap effect). In Experiment 1, a gap effect was observed for vergence eye movements. In Experiment 2, a gap effect was observed for saccades directed at a target that appeared during visual pursuit of a moving stimulus. In Experiment 3, a gap effect was observed for saccades directed at a target that appeared during extrafoveal fixation. The present results extend reports of the gap effect for saccadic shifts during visual fixation to (a) vergence shifts during visual fixation, (b) saccadic shifts during smooth visual pursuit, and (c) saccadic shifts during extrafoveal fixation. The present findings are discussed with respect to the incompatible goals of fixation-locking and fixation-shifting oculomotor responses.     

Pattern recognition and eye-movement parameters

Pattern perception was studied by recording eye movements while Ss visually scanned nine simultaneously presented patterns of asterisks for target patterns. Pattern parameters studied were: similarity of target patterns to non-target patterns (absolute difference in the number of elements), number of target elements, and frequency of targets. Systematic correlation between the first two pattern parameters and eyemovement parameters were found. Mean duration and mean number of fixations on targets and also on non-targets increased with increased similarity. Mean duration and mean number of fixations increased on targets with an increase in the number of target elements. Non-target patterns were perceived more auicfely than targets. Fixations of longer duration were required to perceive the original target than to identify the other target patterns subsequently. The eye-movement results provide the basis for developing inferences about higher order processing of visual stimuli.     

High regularities in eye-movement patterns reveal the dynamics of the visual working memory allocation mechanism

With only two to five slots of visual working memory (VWM), humans are able to quickly solve complex visual problems to near optimal solutions. To explain the paradox between tightly constrained VWM and impressively complex human visual problem-solving ability, we propose several principles for dynamic VWM allocation. In particular, we propose that complex visual information is represented in a temporal manner using only a few slots of VWM that include global and local visual chunks. We built a model of human traveling salesman problem solving based on these principles of VWM allocation and tested the model with eye-movement data. Exactly as the model predicted, human eye movements during traveling salesman problem solving have precise quantitative regularities with regard to both the general statistical pattern of attentional fixations and how they vary across individuals with different VWM capacities. Even though VWM capacity is very limited, eye movements dynamically allocate VWM resources to both local and global information, enabling attention to fine details without loss of the big picture.     

The role of attention in eye-movement awareness

People are unable to accurately report on their own eye movements most of the time. Can this be explained as a lack of attention to the objects we fixate? Here, we elicited eye-movement errors using the classic oculomotor capture paradigm, in which people tend to look at sudden onsets even when they are irrelevant. In the first experiment, participants were able to report their own errors on about a quarter of the trials on which they occurred. The aim of the second experiment was to assess what differentiates errors that are detected from those that are not. Specifically, we estimated the relative influence of two possible factors: how long the onset distractor was fixated (dwell time), and a measure of how much attention was allocated to the onset distractor. Longer dwell times were associated with awareness of the error, but the measure of attention was not. The effect of the distractor identity on target discrimination reaction time was similar whether or not the participant was aware they had fixated the distractor. The results suggest that both attentional and oculomotor capture can occur in the absence of awareness, and have important implications for our understanding of the relationship between attention, eye movements, and awareness.     

A computer system for processing eye-movement records

A computer system using the LINC-8 computer was developed to process eye-movement records from two 16-mm cine film input sources : the Mackworth stand camera and the Mackworth wide-angle camera. Data reduction was accomplished by projecting the films onto an X-Y plotting table. An operator marked, using a cursor, either the eyespot, in the case of the stand camera, or the pupil and display center, in the case of the wide-angle camera, in order to digitize the locus of the gaze. This information was normalized and stored on magnetic tape as: ordinal fixation number, fixation duration, and fixation coordinates (X and Y). A software library was created to analyze the three eye-movement measures. One program calculates interfixation distance, fixation time, and dispersion of fixations about a point. A second program operates on data matrices to: calculate area covered by a fixation pattern, frequency of redundant fixations in a fixation pattern, and distribution of fixations over features of the visual display. Data are displayed on either scope or the Calcomp plotter.     

Lateral eye-movement responses to visual stimuli

The association of left lateral eye-movement with emotionality or arousal of affect and of right lateral eye-movement with cognitive/interpretive operations and functions was investigated. Participants were junior and senior students enrolled in an undergraduate course in developmental psychology. There were 37 women and 13 men, ranging from 19 to 45 yr. of age. Using videotaped lateral eye-movements of 50 participants' responses to 15 visually presented stimuli (precategorized as neutral, emotional, or intellectual), content and statistical analyses supported the association between left lateral eye-movement and emotional arousal and between right lateral eye-movement and cognitive functions. Precategorized visual stimuli included items such as a ball (neutral), gun (emotional), and calculator (intellectual). The findings are congruent with existing lateral eye-movement literature and also are additive by using visual stimuli that do not require the explicit response or implicit processing of verbal questioning.     

Differentiating between verbal and spatial encoding using eye-movement recordings

Visual information processing is guided by an active mechanism generating saccadic eye movements to salient stimuli. Here we investigate the specific contribution of saccades to memory encoding of verbal and spatial properties in a serial recall task. In the first experiment, participants moved their eyes freely without specific instruction. We demonstrate the existence of qualitative differences in eye-movement strategies during verbal and spatial memory encoding. While verbal memory encoding was characterized by shifting the gaze to the to-be-encoded stimuli, saccadic activity was suppressed during spatial encoding. In the second experiment, participants were required to suppress saccades by fixating centrally during encoding or to make precise saccades onto the memory items. Active suppression of saccades had no effect on memory performance, but tracking the upcoming stimuli decreased memory performance dramatically in both tasks, indicating a resource bottleneck between display-controlled saccadic control and memory encoding. We conclude that optimized encoding strategies for verbal and spatial features are underlying memory performance in serial recall, but such strategies work on an involuntary level only and do not support memory encoding when they are explicitly required by the task.     

General software for an on-line eye-movement recording system

A general on-line eye-movement recording system is described which consists basically of (a) some on-line instrument capable of displaying a visual scene, (b) a device to measure eye position and output position information in the form of electrical signals (c) an analogue-to-digital converter, and (d) a computer. General software for such a system is discussed with emphasis on subroutines which perform calibration and which continuously monitor eye position.     

Resolving syntactic category ambiguity: An eye-movement analysis

In two experiments, participants' eye movements were monitored as they read sentences containing biased syntactic category ambiguous words with either distinct (e.g., duck) or related (e.g., burn) meanings or unambiguous control words. In Experiment 1, prior context was consistent with either the dominant or subordinate interpretation of the ambiguous word. The subordinate bias effect was absent for the ambiguous words in gaze duration measures. However, effects of ambiguity did emerge in other measures for the ambiguous words preceded by context supporting the subordinate interpretation. In Experiment 2, context preceding the target words was neutral. Ambiguity effects only arose when posttarget context was consistent with the subordinate interpretation of the ambiguous words, indicating that readers initially selected the dominant interpretation. Results support immediate theories of syntactic category ambiguity resolution, but also suggest that recovery from misanalysis of syntactic category ambiguity is more difficult than for lexical-semantic ambiguity in which alternate interpretations do not cross syntactic category.     

Lateral eye-movement consistency and academic aptitude: failure to replicate.

Scores on the Scholastic Aptitude Test were compared for 52 right and 46 left Ss directionally consistent and directionally inconsistent (n = 62) for conjugate lateral eye movements elicited by reflection in interpreting a series of 10 proverbs. The finding of lower Scholastic Aptitude Test scores for Ss inconsistent in direction of eye movement (Weiten & Etaugh, 1974) was not confirmed.     

Perception of object-context relations: eye-movement analyses in infants and adults

Twenty-eight 4-month-olds' and twenty-two 20-year-olds' attention to object-context relations was investigated using a common eye-movement paradigm. Infants and adults scanned both objects and contexts. Infants showed equivalent preferences for animals and vehicles and for congruent and incongruent object-context relations overall, more fixations of objects in congruent object-context relations, more fixations of contexts in incongruent object-context relations, more fixations of objects than contexts in vehicle scenes, and more fixation shifts in incongruent than congruent vehicle scenes. Adults showed more fixations of congruent than incongruent scenes, vehicles than animals, and objects than contexts; equal fixations of animals and their contexts but more fixations of vehicles than their contexts; and more shifts of fixation when inspecting animals in context than vehicles in context. These findings for location, number, and order of eye movements indicate that object-context relations play a dynamic role in the development and allocation of attention.     

Predicting eye-movement characteristics across multiple tasks from working memory and executive control

Individual differences in working memory (WM) and executive control are stable, related to cognitive task performance, and clinically predictive. Between-participant differences in eye movements are also highly reliable (Carter & Luke, Journal of Experimental Psychology: Human Perception and Performance, 2018; Henderson & Luke, Journal of Experimental Psychology: Human Perception and Performance, 40(4), 1390–1400, 2014). However, little is known about how higher order individual differences in cognition are related to these eye-movement characteristics. In the present study, healthy college-age participants performed several individual difference tasks to measure WM span and executive control. Participants also performed three eye-movement tasks: reading, visual search, and scene viewing. Across all tasks, higher WM scores were related to reduced skewness in fixation duration distributions. In reading, higher WM scores predicted longer saccades. In scene viewing, higher WM scores predicted longer fixations. Theoretical and clinical implications of these findings are discussed.     

Temporal and spatial characteristics of attention to facilitate manual and eye-movement responses

Previous investigation found that the speed of saccadic eye movements is enhanced when a temporal interval (gap) is introduced between the disappearance of a foveal fixation mark and the appearance of a peripheral target (the gap paradigm). Attention was shown to be involved in the gap paradigm. Here, we investigated relevant temporal and spatial characteristics of attention, manipulating central fixation marks and peripheral targets. Results from three experiments indicate that (i) the speed of manual and eye-movement detection is accelerated when a fixation mark changes abruptly (in less than 100 ms) before its termination in the gap paradigm; (ii) the speed is further accelerated when a peripheral target location is pre-cued; (iii) sufficient time for fixation (1000 ms) is necessary for the facilitation. These results suggest that fast and transient attention at the fixation spot facilitates attentional disengagement process that urges a spatial-orienting mechanism. Sustained attention is required in the engagement process during the fixation.     

Calibration of an eye-movement system for use in reading

A method for measuring horizontal eye movements in the msec range is described. Accurate measurement of horizontal eye movement over a linear range of 12° is achieved by processing the image of the eye illuminated with infrared light and with the head position fixed. The system has given very reliable results, and a resolution of 6 min of visual angle can be achieved with a character space of 45 min of arc. We also describe efficient numerical-data processing which allows the precise determination of the absolute position of the eye.