PubMed · 5363062
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W H Melanowski. 1969. [Central and peripheral vision].. https://pubmed.ncbi.nlm.nih.gov/5363062/
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In two experiments, eye movements were monitored as participants followed spoken instructions to click on and move pictures with a computer mouse. In Experiment 1, a referent picture (e.g., the picture of a bench) was presented along with three pictures, two of which had names that shared the same initial phonemes as the name of the referent (e.g., bed and bell). Participants were more likely to fixate the picture with the higher frequency name (bed) than the picture with the lower frequency name (bell). In Experiment 2, referent pictures were presented with three unrelated distractors. Fixation latencies to referents with high-frequency names were shorter than those to referents with low-frequency names. The proportion of fixations to the referents and distractors were analyzed in 33-ms time slices to provide fine-grained information about the time course of frequency effects. These analyses established that frequency affects the earliest moments of lexical access and rule out a late-acting, decision-bias locus for frequency. Simulations using models in which frequency operates on resting-activation levels, on connection strengths, and as a postactivation decision bias provided further constraints on the locus of frequency effects.
Better understanding of the functions and abilities underlying some neurobehavioral tests would assist the assessment of the consequences to the health or well-being of exposed populations for which decrements in such tests have been found. Eye movements, which can be useful in evaluating specific theories of visual and cognitive processes, were measured while a single participant completed the NES Symbol-Digit Substitution test. Relationships between the durations and the frequencies of eye fixations within different parts of the test material and overall test performance were examined. The overall pattern of eye-movement behavior observed was as predicted: fixations within three regions of visual interest were made, usually in the order lower matrix, upper matrix, keyboard. Both the upper matrix fixation latency and the number of regional fixations made per item were found to be strongly associated with overall item response latency. This suggests that speed and efficiency of searching and the ability to maintain concentration appeared to be key attributes related to test performance for this participant. For suitable tests, eye-movement data may be useful for assessing and measuring the latencies of subtask components in a real test situation. Monitoring eye movement represents an alternative methodology to using sub test composites, or factor analysis, as a means of tapping into the functions underlying neurobehavioral test performance.
Relatively little is known about movements of the eyes, head, and hands in natural tasks. Normal behavior requires spatial and temporal coordination of the movements in more complex circumstances than are typically studied, and usually provides the opportunity for motor planning. Previous studies of natural tasks have indicated that the parameters of eye and head movements are set by global task constraints. In this experiment, we explore the temporal coordination of eye, head, and hand movements while subjects performed a simple block-copying task. The task involved fixations to gather information about the pattern, as well as visually guided hand movements to pick up and place blocks. Subjects used rhythmic patterns of eye, head, and hand movements in a fixed temporal sequence or coordinative structure. However, the pattern varied according to the immediate task context. Coordination was maintained by delaying the hand movements until the eye was available for guiding the movement. This suggests that observers maintain coordination by setting up a temporary, task-specific synergy between the eye and hand. Head movements displayed considerable flexibility and frequently diverged from the gaze change, appearing instead to be linked to the hand trajectories. This indicates that the coordination of eye and head in gaze changes is usually the consequence of a synergistic linkage rather than an obligatory one. These temporary synergies simplify the coordination problem by reducing the number of control variables, and consequently the attentional demands, necessary for the task.