Precueing attention to the target location diminishes crowding and reduces the critical distance

Abstract

The identification of a peripheral target surrounded by flankers is often harder than the identification of an identical isolated target. This study examined whether this crowding phenomenon, and particularly its spatial extent, is affected by the allocation of spatial attention to the target location. We measured orientation identification of a rotated T with and without flankers. The distance between the target and the flankers and their eccentricity varied systematically. We manipulated attention via peripheral precues: in the cued condition, a dot indicated the target location prior to its onset. On the neutral condition, a central disk conveyed no information regarding the target location (Experiments 1-2), and on the invalid condition (Experiment 3), an invalid cue attracted attention to a nontarget location. We found, across all experiments, at all eccentricities, a significant attentional enhancement of identification accuracy. Most importantly, we found a significant attentional reduction of the critical distance (i.e., the target-flankers distance at which the flankers no longer interfere with target identification). These attentional effects were found regardless of the presence or absence of a backward mask and whether the attentional cue was informative or not. These findings suggest that attention reduces the spatial extent of crowding.

Extra-large letter spacing improves reading in dyslexia

“…The beneficial effect of extra-large letter spacing might also be linked to sluggish visuospatial attention in dyslexic children (7,36). Indeed, spatial attention diminishes crowding by improving accuracy of target identification or reducing the critical spacing (21,37). Sluggish spatial attention has recently been observed even in at-risk prereaders who later became dyslexic (38,39).…”

Enhancement of perceptual representations by endogenous attention biases competition in response selection

“…Because the eccentricity of our targets was 6°visual angle, our closest edge-to-edge distance between stimuli of 4°is unlikely to have produced significant crowding. Yeshurun and Rashal (2010) showed that spatial attention further reduces the target-flanker distance at which the flankers no longer interfere with the target identification. Second, Pelli, Palomares & Majaj (2004) have reported that crowding affects feature detection, which was not necessary to solve our task.…”

Mechanisms behind Perisaccadic Increase of Perception

“…One proposed mechanism for maintaining stability is predictive remapping of neurons' visual fields just before the eyes actually start to move (for review, see Melcher, 2011). With predictive remapping, the receptive field of some neurons shifts toward the location they will occupy after the eye movement (Duhamel et al, 1992). It is hypothesized that predictive remapping is driven by an efference copy of the motor command that is sent back to the oculomotor cortex, informing the brain about the upcoming eye movement.…”

“…A study by Harrison et al (2013) investigated whether predictive remapping causes peripheral targets to be released from crowding just before an eye movement is made. In the first experiment, participants were asked to report the orientation of a small, peripherally-presented stimulus that was crowded by four vertically oriented stimuli (flankers).…”