Attention and spatial selection: Electrophysiological evidence for modulation by perceptual load

Abstract

Behavioral data have suggested that perceptual load can modulate spatial selection by influencing the allocation of attentional resources at perceptual-level processing stages (Lavie& Tsal, 1994). To directly test this hypothesis, event-related potentials (ERPs) were recorded for both low-and highperceptual-load targets in a probabilistic spatial cuing paradigm. The results from three experiments showed that, as measured by the lateral occipital PI and Nl ERP components, the magnitude of spatially selective processing in extrastriate visual cortex increased with perceptual load. Furthermore, these effects on spatial selection were found in the PI at lower levels of perceptual load than in the Nl. The ERP data thus provide direct electrophysiological support for proposals that link perceptual load to early spatial selection in visual processing. However, our findings suggest a relatively broader model-where perceptual load is but one of many factors mediating early selection.By modulating the flow of sensory information in the brain, selective attention serves as the arbiter between perception and action in the natural environment (e.g., Cowan, 1995;Desimone & Duncan, 1995;LaBerge, 1995;Pashler, 1998). In vision, selection can occur within a spatial frame of reference, with stimuli in attended spatial locations receiving preferential processing relative to stimuli occurring in unattended spatial locations (e.g., Naatanen, 1992). For example, manual responses to nonfoveal visual targets are quicker and more accurate when the target is presented at an attended visual field location than when the target is presented at an unattended visual field location (e.g.,

Stimulus onset asynchrony and the timeline of word recognition: Event-related potentials during sentence reading

“…Together, these findings support the notion that early processes are primarily engaged when perceptual load and task requirements are high (Handy & Mangun, 2000;Lavie, 1995Lavie, , 2005Lavie & Tsal, 1994;Luck, Woodman, & Vogel, 2000).…”

ERPs reveal similar effects of social gaze orienting and voluntary attention, and distinguish each from reflexive attention

“…Given that many previous studies have shown effects of voluntary attention at early stages of processing (e.g., Eimer, 1994b;Mangun & Hillyard, 1991), we do not suggest that the present results should be interpreted as evidence that voluntary and social orienting cannot affect these levels of processing. Rather, the present results lend further support to the argument that the effects of voluntary attention on early visual processing are sensitive to task demands and perceptual load (Handy & Mangun, 2000). Indeed, small and/or nonexistent effects of voluntary orienting on early sensory processing are not an uncommon finding when using a localization task (Eimer, 1994a;Prime & Ward, 2006), such as the one used in this study.…”

“…For example, some studies have found that gaze cuing enhances the amplitude of the target-evoked P1 component (e.g., Schuller & Rossion, 2001, while others have shown no evidence of amplitude modulation of early visual processing by social gaze cuing (Fichtenholtz, Hopfinger, Graham, Detwiler, & LaBar, 2007Magnée, Kahn, Cahn, & Kemner, 2011). Thus, it may be the case that the ERP effects of social gaze orienting may be sensitive to the perceptual and cognitive loads induced by the task and stimuli, as has been shown for voluntary attention (e.g., Eimer, 1994a;Handy & Mangun, 2000;Prime & Ward, 2006;Vogel & Luck, 2000). In addition, theories of attention based on overt behavior have often assumed multiple types of attention processes, and that some mechanisms may be differentially involved, depending on the task and stimulus parameters (see, e.g., Dosher, 1998, andPrinzmetal et al 2005).…”

Tracking the influence of reflexive attention on sensory and cognitive processing

“…An enhancement of the P1 component occurs for all stimuli at a voluntarily attended location, arguing that it indexes focal spatial attention (e.g., Heinze, Luck, Mangun, & Hillyard, 1990;Luck, Fan, & Hillyard, 1993;Mangun & Hillyard, 1991). However, recent studies have shown that task demands can play a role in voluntary P1 attention effects (e.g., Eimer, 1994;Handy & Mangun, 2000). Handy & Mangun showed that the P1 attention effect was observed only when attention was induced to be strongly focused on the attended location (under conditions of high perceptual load).…”