Spatial attention: Different mechanisms for central and peripheral temporal precues?

Abstract

The external noise paradigm (Z.-L. Lu & B. A. Dosher, 1998) was applied to investigate mechanisms of spatial attention in location precuing. Observers were precued or simultaneously cued to identify 1 of 4 pseudocharacters embedded in various amounts of external noise. The cues were either central or peripheral. Both central and peripheral precuing significantly reduced threshold in the presence of high external noise (16% and 17.5%). Only peripheral precuing significantly reduced threshold in the presence of low, or no, external noise (11%). A perceptual template model identified different mechanisms of attention for central and peripheral precuing, external noise exclusion for central precuing, and a combination of external noise exclusion and stimulus enhancement (or equivalently, internal additive noise reduction) for peripheral cuing.In a high workload environment, a human operator might need to monitor a large number of information sources simultaneously. Whereas this might be accomplished by saccades, the eye movement system is limited by the relatively long time (about 200 ms) each saccade takes (Hallett, 1986). On the other hand, the existence of a faster spatial attention system was proposed about a century ago (Helmholtz, 186671911;Wundt, 1902), selecting regions of the visual field for further processing without eye movements. This view has been established by the more recent literature

Transient covert attention does alter appearance: A reply to Schneider (2006)

“…This conclusion is consistent with the "linking hypothesis," which states that the attentional enhancement of neural firing is interpreted as if the stimulus had a higher contrast (Reynolds & Chelazzi, 2004;Treue, 2004). This proposal is supported by converging evidence from neurophysiological (Martinez-Trujillo & Treue, 2002, Reynolds, Pasternak, & Desimone, 2000, psychophysical (e.g., Carrasco, Ling, & Read, 2004;Carrasco, Penpeci-Talgar, & Eckstein, 2000;Lu & Dosher, 2000) and neuroimaging (Liu, Pestilli, & Carrasco, 2005) studies (for a review, see Carrasco, 2006).…”

Revisiting the spread of sparing in the attentional blink

“…This idea is consistent with the argument that a critical function of attention in perceptual processing is to exclude external noise in the target region (Dosher & Lu, 2000a, 2000bLu & Dosher, 2000;Lu, Lesmes, & Dosher, 2002). Empirical work has also demonstrated that the impact of attention upon perceptual processing can be enhanced by the perceptual difficulty of target processing.…”

Working memory-driven attention improves spatial resolution: Support for perceptual enhancement

“…It has been proposed in the attention literature that signal enhancement and external noise reduction are two separate but not mutually exclusive mechanisms underlying attentional effects on visual processing (e.g., Carrasco, 2011;Carrasco, Williams, & Yeshurun, 2002;Dosher & Lu, 2000a;Lu & Dosher, 2000). In this view, sensory enhancement may not be the sole mechanism for effects of working memorydriven attention on visual identification or discrimination.…”