Saccades require focal attention and are facilitated by a short-term memory system

Abstract

We performed two sets of experiments in which observers were instructed to make saccades to an odd colored target embedded in an array of distractors. First, we found that when the colors of the target and distractors switched unpredictably from trial to trial (the mixed condition), saccadic latencies decreased with increasing numbers of distractors. In contrast, saccadic latencies were independent of the number of distractors when the color of the target and distractors remained the same on each trial (the blocked condition). This pattern of results mirrors visual search tasks in which focal rather than distributed attention is required (Bravo, M.J., Nakayama, K. (1992). The role of attention in different visual search tasks. Perception and Psychophysics, 51, 465-472.). Second, we found that saccades to an odd target were made more quickly and accurately when the target was the same color as on previous trials than when it changed color. This priming of the target color accumulates across five to seven trials over a period of approximately 30 s. A similar priming effect has been previously shown for the deployment of focal attention (Maljkovic, V., Nakayama, K. (1994). Priming of popout: III. Role of features. Memory and Cognition, 22(6), 657-672.). Thus, we show a close congruence between the pattern of saccadic eye movement latencies and the deployment of focal attention. This supports the view that (1) the execution of saccades requires focal as opposed to distributed attention and that (2) this focal attention is guided by a short term memory system which facilitates the rapid refixation of gaze to recently foveated targets.

Exploring the contributions of spatial and non-spatial working memory to priming of pop-out

“…In a similar vein, the Bgaze reorientation^hypothesis argued by Maljkovic and Nakayama (1996) proposes that PoP and position-based priming (in a PoP task) depend on a representation in a Bshort-term memory,^which is the basis of reorienting eye gaze to an object or location involved in a sequence of actions. Later eye movement studies (McPeek, Maljkovic, & Nakayama, 1999) supported the gaze reorientation hypothesis by showing that saccades to a target were faster and more accurate when the target color was repeated across trials. This result indicates that the underlying mechanism of PoP is responsible for rapidly reorienting the observer's gaze to a recently foveated target.…”

Distinct neural networks for target feature versus dimension changes in visual search, as revealed by EEG and fMRI

“…shown that target feature changes indeed bias attention and the gaze to the nontargets (e.g., Becker, 2008aBecker, ,b,c, 2010aBecker, ,b, 2013McPeek, Maljkovic & Nakayama, 1999).…”

“…This two-system hypothesis is currently supported by three major findings. First, altering the target feature usually delays eye movements to the target (e.g., Becker, 2008aBecker, , b, c, 2013McPeek et al, 1999), whereas changing the target dimension does not interfere with selection of the target but rather prolongs target dwell times (e.g., Becker, 2010a). Second, electroencephalography (EEG) studies have found that swapping the target and non-target features leads to large delays in the onset of the N2pc (~50ms; Eimer, Kiss & Cheung, 2010), an electrophysiological marker for spatial attentional selection (e.g., Eimer, 1996;Luck & Hillyard, 1994), whereas dimension changes have only small effects on N2pc latencies (~8ms; e.g., Töllner et al, 2008;6ms, Töllner et al, 2010, Rangelov et al, 2013 that cannot account for the substantial RT delay of 30-50ms.…”

Differential Influence of Attention on Gaze and Head Movements

“…The role of attention in saccadic eye movements has been studied extensively in head-restrained conditions. It has been established that saccade execution requires a shift of attention to the saccade goal (e.g., Deubel and Schneider 1996;Hoffman and Subramaniam 1995;Kowler et al 1995;McPeek et al 1999), indicating a close linkage between eye movements and attention. Such a linkage is also supported by a number of studies showing shared neural substrates for saccadic eye movement planning and attentional processing (e.g., Beauchamp et al 2001;Cavanaugh and Wurtz 2004;Corbetta et al 1998;Goldberg et al 2006;Ignashchenkova et al 2004;Kastner and Ungerleider 2000;Moore and Fallah 2001;Muller et al 2005; Thompson et al 2005).…”