The Spatial Resolution of Visual Attention (original) (raw)

On the spatial extent of attention in object-based visual selection

1996

Abstract A new test was devised to avoid previous confounds in measures of object-based limits on divided visual attention. The distinction between objects was manipulated across a wide spatial extent. Target elements appeared on the same object only when far apart, and appeared close only when on different objects, so that object effects could not be reduced to spatial effects, nor vice versa. Subjects judged whether two odd elements within a display of two dashed lines were the same or different.

Spatial Spread of Visual Attention while Tracking a Moving Object

Optical Review, 2007

We conducted three experiments to investigate the spatial spread of visual attention. In Experiment 1, we measured the contrast sensitivities at various locations (spatial sensitivity function) relative to the moving target that the observer attended to track in an attentive tracking display. A probe was presented at a distance from the target at a location randomly chosen from within a certain range. The range of probe presentation location varied to examine whether the observer changes the area of attention to cope with this range. The results show that the probe range influenced the shape of spatial sensitivity function. The change in shape of this function suggests that the observer covers a wider area with attention for large probe ranges than small probe ranges. In the following experiments, we investigated the effect of the distance between the tracking target and a probe at a fixed location relative to the target (Experiment 2), or between the target and the center of a probe range of fixed size (Experiment 3). Since the relative probe location in a session was fixed in the experiments, the observer would pay attention to the target and probe locations independently of the relative distance if he/she could focus attention at multiple locations. Spatial sensitivity functions obtained in Experiments 2 and 3 showed that this was not the case. In both experiments the sensitivity to the probe decreased with increase in the relative distance as in Experiment 1, where the probe was presented at a location randomly chosen within each range. This indicates that attention cannot be divided among multiple locations, at least under the present experimental conditions. We will discuss a possible interpretation of the present results with a limited attentional resource and its spatial distribution.

Shifting of attentional focus within and about a visual display

Attention Perception & Psychophysics, 1989

If several positions must be attended in a large visual display, does the efficiency of performance vary as a function of the display distance between these to-be-attended positions? Two previous experiments (Podgorny &Shepard, 1983; Shaw, 1978) gave conflicting answers. In the present experiments, eight-letter circular displays were briefly presented. On each trial one, two, or three positions of the display were cued or precued. The number of noncued display positions intervening between the cued locations varied from zero to three. The subjects’ task was to rapidly discriminate between two target letters. Although reaction time was found to increase with increases in the number of cued locations, no significant or suggestive effects were found for the spacing or distance between the cued locations. The evidence strongly suggests that the subjects serially searched the cued locations, which further implies that attention can index locations in the visual field at a speed that is independent of the distance between these locations.

The effect of attentional spread on spatial resolution

Vision research, 1997

The effects of attentional spread were studied by having subjects detect a luminance increment along a row of evenly spaced dots. The increment could occur for the central, fixated dot (Narrow Attention) or for either the fixation dot or one of the four dots to its left or right (Broad Attention). Narrow Attention enhanced the detection of luminance increments for the fixated dot, and also enhanced spatial resolution near the fixation dot for judgments of vernier alignment and separation. This indicated that the sensitivity of small spatial filters in the fovea was increased more by narrowly focused than broadly spread attention. Effects of attentional spread on spatial resolution were not obtained for judgments of the separation between two peripherally located targets, perhaps because of their dependence on eccentricity (position) rather than separation.