Abstract
Salient peripheral events trigger fast, “exogenous” covert orienting. The influential premotor theory of attention argues that covert orienting of attention depends upon planned but unexecuted eye-movements. One problem with this theory is that salient peripheral events, such as offsets, appear to summon attention when used to measure covert attention (e.g., the Posner cueing task) but appear not to elicit oculomotor preparation in tasks that require overt orienting (e.g., the remote distractor paradigm). Here, we examined the effects of peripheral offsets on covert attention and saccade preparation. Experiment 1 suggested that transient offsets summoned attention in a manual detection task without triggering motor preparation planning in a saccadic localisation task, although there were a high proportion of saccadic capture errors on “no-target” trials, where a cue was presented but no target appeared. In Experiment 2, “no-target” trials were removed. Here, transient offsets produced both attentional facilitation and faster saccadic responses on valid cue trials. A third experiment showed that the permanent disappearance of an object also elicited attentional facilitation and faster saccadic reaction times. These experiments demonstrate that offsets trigger both saccade programming and covert attentional orienting, consistent with the idea that exogenous, covert orienting is tightly coupled with oculomotor activation. The finding that no-go trials attenuates oculomotor priming effects offers a way to reconcile the current findings with previous claims of a dissociation between covert attention and oculomotor control in paradigms that utilise a high proportion of catch trials.
Highlights
Humans exist in a complex visual environment
We demonstrated that disrupting saccade preparation by presenting stimuli beyond the range of saccadic eye-movements interferes with exogenous orienting to peripheral onsets but not endogenous orienting to symbolic cues (Smith, Rorden, & Schenk, 2012) or gaze cues (Morgan, Ball, & Smith, 2014)
This study tested the hypothesis that transient offset cues would summon attention without triggering activation of a saccade plan. Consistent with this hypothesis, valid cues produced significant reaction time (RT) facilitation for manual responses but not saccadic response. These data appear to show that attention was oriented to the cued location but that no saccade plan was activated
Summary
Humans exist in a complex visual environment. Given the limitations on information processing capacity, a key challenge faced by the visual system is the selection of task-relevant visual signals from irrelevant noise. The same manipulation affects exogenous orienting in feature search but not endogenous orienting in conjunction search (Smith, Ball, & Ellison, 2014; Smith, Ball, Ellison, & Schenk, 2010) and encoding and rehearsal of spatial, but not visual working memories (Ball, Pearson, & Smith, 2013; Pearson, Ball, & Smith, 2014) This pattern of specific disruption to exogenous attention by disruption to the oculomotor system can be observed in clinical populations; patients with oculomotor deficits typically present with defective exogenous orienting but largely preserved endogenous orienting (Gabay, Henik, & Gradstein, 2010; Rafal, Posner, Friedman, Inhoff, & Bernstein, 1988; Smith, Rorden, & Jackson, 2004), see Craighero, Carta, and Fadiga (2001). The claim that offsets can summon attention without triggering saccade programming leads to a clear prediction; there should be attentional facilitation in the manual detection and discrimination task but no facilitation of SRT in the saccadic localisation task
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