Visual attention within and around the field of focal attention: A zoom lens model

Abstract

The operation of attention in the visual field has often been compared to a spotlight. We propose that a more apt analogy is that of a zoom or variable-power lens. Two experiments focused upon the following questions: (1) Can the spatial extent of the attentional focus be made to vary in response to precues? (2) As the area of the attentional focus increases, is there a decrease in processing efficiency for stimuli within the focus? (3) Is the boundary of the focus sharply demarked from the residual field, or does it show a gradual dropoff in processing resources? Subjects were required to search eight-letter circular displays for one of two target letters and reaction times were recorded. One to four adjacent display positions were precued by underlines at various stimulus onset asynchronies before display presentation. A response competition paradigm was used, in which the "other target" was used as a noise letter in noncued as well as cued locations. The results were in good agreement with the zoom lens model. Much of our information about the operation of attention in the visual field has been obtained from visual search tasks or modifications of this procedure. When visual displays are presented at durations too brief to permit saccadic eye movements, accuracy in identifying targets in the display or the time required to do so can be presumed to reflect underlying visual attentional processes.Two salient findings have emerged from this research on visual attention. One fmding is that under certain conditions the resources of the attentional system seem to be distributed evenly over a display, with parallel

The impact of Degraded distractors on (Nondegraded) target identification

“…The effect depends on two factors: first, the location of the distractors in the visual field, and thus presumably on the amount of attentional resources that may be allocated to them. Distractors at fixation receive more attentional resources and are processed more efficiently (Beck and Lavie, 2005;Eriksen & St James, 1986;Kritikos et al, in press). Consistent with this, performance (reaction time and accuracy) was better for targets presented alone at fixation, than at periphery; moreover, distractors had a greater impact when they were presented at fixation rather than periphery.…”

“…One possibility for this is that distractors always appeared in the periphery, where relatively fewer attentional resources are directed (Eriksen & St James, 1986). Indeed, Beck and Lavie (2005) and Kritikos, McNeil and Pavlis (submitted) have shown that distractors presented at fixation caused greater interference (slower response times and reduced accuracy) than distractors presented at periphery.…”

Blink and Shrink: The Effect of the Attentional Blink on Spatial Processing.

“…Thus, under this scenario, attention may not be temporarily unavailable for spatial processing-instead, it is available but not in the right shape. I refer to this as the zoom lens explanation of the results (Eriksen & St. James, 1986), and Experiment 2 tested for this possibility. A second alternative is that the lapse in performance is due to general task switching demands (as participants need to switch from the RSVP detection task to the cued visual search task), rather than to an attentional blink induced by the perceptual processing of an RSVP target.…”

Selective Attention and the Perception of an Attended Nontarget Object.

“…A. Eriksen & Eriksen, 1974; C. W. Eriksen & St. James, 1986;MacLeod, 1991). Kahneman and Chajczyk's (1983) study has further suggested that the extent of processing of a distractor may even extend to its irrelevant dimension.…”