Limits of focused attention in three-dimensional space

Abstract

The present experiment examined the shape of the attentional gradient in three-dimensional space. Subjects performed a response-compatibility task in which they were instructed to respond to a centrally located target and ignore flanking distractors. The irrelevant distractors were presented at combinations of seven different depths, three different horizontal separations, and three different vertical separations relative to the target. Depth was varied in a stereoscopic display viewed through polarized glasses. Overall, the size of the response-compatibility effect decreased with increased separation in all three dimensions. Interestingly, the response-compatibility effect was larger for horizontal separations than for vertical separations and was larger for crossed disparities than for uncrossed disparities. The results suggest an elliptical focus of attention, with steeper gradients in the vertical dimensions than in the horizontal dimensions. In addition, the results suggest, along the vertical dimension, a steeper gradient for objects located beyond the focus of attention relative to that for objects located between the observer and the focus of attention.Over the past two decades, there has been considerable interest in the dynamics of visual attention. An important focus of this body of research has been the relation between the size of the attentional focus and processing efficiency. For example, models based on a spotlight analogy have argued that stimuli that fall within the beam of the spotlight receive full processing, whereas stimuli that are located outside of the boundaries of the spotlight are ignored (Broadbent,

Inhibition of return spreads across 3-D space

“…This difference in depth cuing was not reliable (F 5 0.27), indicatingthat there was no asymmetry effect in attending to the front or to the back. It is worth noting that asymmetry effects have been reported in some studies (e.g., Andersen, 1990;Andersen & Kramer, 1993) but not in others (e.g., Theeuwes et al, 1998). Currently, there is no clear evidence as to what the mitigating factor might be, but our results clearly indicate no asymmetry in orienting attention between depth planes at a short SOA.…”

Spatial distribution of visual attention: Perceptual sensitivity and response latency

“…These and similar findings (see below) have led to the "gradient" hypothesis, which proposes that the effects ofattention on response performance decline with increasing distance from the attended location. This conceptualization ofan attentional gradient has received much support (Andersen, 1990;Andersen & Kramer, 1993;Egly & Homa, 1991;Henderson, 1991;Henderson & Macquistan, 1993;Klein & McCormick, 1989;LaBerge & Brown, 1989;Mangun & Hillyard 1987,1988.…”

Visual search is influenced by 3D spatial layout

“…The zoom lens model (Eriksen & St James, 1986) extended this analogy with the idea of scale adjustment, such that the size of the spotlight can be adjusted according to the task at hand. The attentional spotlight also has been described as a volume extending in depth, based on measured reaction times to targets flanked by distractors at different distances in depth from the target (Andersen, 1990;Andersen & Kramer, 1993). Andersen and Kramer (1993) describe the attentional spotlight as viewer-centered, concentrated between the observer and the point of fixation, with attention dropping off steeply beyond.…”

“…The attentional spotlight also has been described as a volume extending in depth, based on measured reaction times to targets flanked by distractors at different distances in depth from the target (Andersen, 1990;Andersen & Kramer, 1993). Andersen and Kramer (1993) describe the attentional spotlight as viewer-centered, concentrated between the observer and the point of fixation, with attention dropping off steeply beyond. Parks and Corballis' (2006) data support the idea of viewer-centered attention in depth, recording response times and event-related potentials (ERPs) while participants attended to near or far depths.…”