For over 25 years, researchers have debated whether physically salient stimuli capture attention in an automatic manner, independent of the observer's goals, or whether the capture of attention depends on the match between a stimulus and the observer's task set. Recent evidence suggests an intermediate position in which salient stimuli automatically produce a priority signal, but the capture of attention can be prevented via an inhibitory mechanism that suppresses the salient stimulus. Here, proponents from multiple sides of the debate describe how their original views have changed in light of recent research, as well as remaining areas of disagreement. These perspectives highlight some emerging areas of consensus and provide new directions for future research on attentional capture.

Recently it was argued that in addition to top-down and bottom-up processes, lingering biases of selection history play a major role in visual selection ( Awh, Belopolsky & Theeuwes, 2012 ). Since its publication there has been a growing controversy about the terms top-down, bottom-up and selection-history in relation to visual selection. In the current paper we define these terms, discuss some controversies about these terms and explain what kind of effects should be considered to be the result of lingering biases of selection history, i.e., priming, reward/fear, and statistical learning. We discuss the properties of top-down selection (slow, effortful, and controlled) versus the properties of lingering biases of selection history (fast, effortless, and automatic). We adhere the position that the experience with selecting a particular feature or the location of a feature, may boost and sharpen its representation within the priority selection map above and beyond its physical salience. It is as if the experience may render a feature or location subjectively more salient. Our message of the current review is that true top-down control of visual selection occurs far less often than what is typically assumed. Most of the time, selection is based on experience and history. It is fast, automatic and occurs without much, if any, effort.

Recently the signal-suppression account was proposed, positing that salient stimuli automatically produce a bottom-up salience signal that can be suppressed via top-down control processes. Evidence for this hybrid account came from a capture-probe paradigm that showed that while searching for a specific shape, observers suppressed the location of the irrelevant color singleton. Here we replicate these findings but also show that this occurs only for search arrays with 4 elements. For larger array sizes when both target and distractor singleton are salient, there is no evidence for suppression; instead and consistent with the stimulus-driven account, there is clear evidence that the salient distractor captured attention. The current study shows that the relative salience of items in the display is a crucial factor in attentional control. In displays with a few heterogeneous items, top-down suppression is possible. However, in larger displays in which both target and distractor singletons are salient, no top-down suppression is observed. We conclude that the signal-suppression account cannot resolve the long-standing debate regarding stimulus-driven and goal-driven attentional capture. Public Significance StatementThis study replicated the critical findings (i.e., suppression effect) reported by Gaspelin, Leonard, and Luck, 2015, when only four elements were presented on the display. Yet with larger search arrays (six and 10 items), the target and distractor singleton become more salient, and then there was no sign of any suppression; instead and consistent with the stimulus-driven account, there is clear evidence that the salient distractor captured attention. We argued that signal suppression (inhibitory processes) occurs only in displays with a limited number of nonsalient elements allowing for a peculiar (most likely serial) search strategy. The current experiment provides the boundary conditions of when top-down suppression is effective.

mong the most fundamental issues of visual attention research is the A extent to which visual selection is controlled by properties of the stimulus or by the intentions, goals, and beliefs of the observer (see e.g., Theeuwes, 1994a;Yantis, 1993). Before selective attention operates, preattentive processes perform some basic analyses segmenting the visual field into functional perceptual units. The crucial question is the extent to which the allocation of attention to these perceptual units is under the goaldirected control of the observer (intentions, goals, beliefs) or under stimulus-driven control. Goal-directed control is referred to as top-down selection and is said to occur when the observer intentionally selects only those objects required to perform the task at hand. Stimulus-driven control is referred to as bottom-up selection and is said to occur when attention is captured by the properties of the stimulus, irrespective of the intentions or goals of the observer.Clear evidence for top-down control is provided by Posner (1980;Posner, Snyder, & Davidson, 1980) in tasks in which a central cue (e.g., an arrowhead) indicates the likely target location. Spatially valid cues typically I thank Chip Folk, Tram Neill, and Art Kramer for their helpful comments on a draft of this chapter.

The present study shows that an abrupt onset cue that is not consciously perceived can cause attentional facilitation followed by inhibition at the cued location. The observation of this classic biphasic effect of facilitation followed by inhibition of return (IOR) suggests that the subliminal cue captured attention in a purely exogenous way. Since IOR is not observed following endogenous shifts of spatial attention, but is observed following exogenous, stimulus-driven shifts of spatial attention, it is unlikely that top-down control settings or other non-attentional effects played a role. The current findings are interpreted in terms of a neurobiological model of visual awareness.