Motion onset captures attention

Although visual motion may seem salient, motion per se does not automatically attract attention. We show here, however, that the onset of motion does indeed attract attention. In three experiments, subjects identified target letters in displays that contained targets and distractors. There was no advantage for moving letters among static ones, but there was an advantage for objects that had recently started to move despite the fact that the motion was uninformative. If some additional time was allowed to elapse after motion onset, inhibition of return slowed responding to the item that had started to move—a further sign that the motion onset had captured attention. Finally, detection of target letters was found to be independent of the number of distractors in the display if the target had undergone motion onset, also indicative of attentional capture. We discuss the adaptive significance of sensitivity to onsets in the presence of a relative insensitivity to ongoing motion.     

Valuable orientations capture attention

Visual attention has long been known to be drawn to stimuli that are physically salient or congruent with task-specific goals. Several recent studies have shown that attention is also captured by stimuli that are neither salient nor task relevant, but that are rendered in a colour that has previously been associated with reward. We investigated whether another feature dimension—orientation—can be associated with reward via learning and thereby elicit value-driven attentional capture. In a training phase, participants received a monetary reward for identifying the colour of Gabor patches exhibiting one of two target orientations. A subsequent test phase in which no reward was delivered required participants to search for Gabor patches exhibiting one of two spatial frequencies (orientation was now irrelevant to the task). Previously rewarded orientations robustly captured attention. We conclude that reward learning can imbue features other than colour—in this case, specific orientations—with persistent value.     

Onset capture requires attention

We studied exogenous cuing caused by an uninformative abrupt onset during a time when subjects were under the influence of the attentional blink. In two experiments, we found a reduced impact of exogenous cuing during the blink time of the attentional blink. The results indicate that involuntary orienting caused by abrupt onsets is sensitive to manipulation of available attentional resources. Thus, onset capture requires attention.     

Additivity of abrupt onset effects supports nonspatial distraction, not the capture of spatial attention

In a recent article, Schreij, Owens, and Theeuwes (2008) reported that abruptly onsetting distractors produce costs in performance even when spatial-cuing effects confirm the presence of a top-down set for color. The authors argued that these results show that abruptly onsetting new objects capture attention independent of a top-down set and, thus, provide conclusive evidence against the theory that attentional capture is contingent on top-down attentional control settings (Folk, Remington, & Johnston, 1992). In the following article, we argue that, contrary to the conclusion drawn by Schreij et al., their own data (1) disconfirm the claim that their abrupt onsets captured spatial attention and (2) are consistent with nonspatial interference accounts of singleton-distractor effects. In support of the nonspatial account, we show that in a paradigm similar to Schreij et al.’s, distractors that do not capture attention can nonetheless influence responses to a target. We conclude that the results of Schreij et al. do not represent a challenge to contingent capture theory.     

Motion onset captures attention: a rejoinder to Franconeri and Simons (2005)

Recently, we have provided evidence that the onset of motion captures attention (Abrams & Christ, 2003, 2005a, 2005b). In the present article, we clarify the motion onset hypothesis, we discuss recent data (Franconeri & Simons, 2005) that, at least on the surface, seem to challenge the hypothesis, and we present results from a new experiment (Christ & Abrams, 2005). Finally, we conclude that, although motion onset does indeed appear to capture attention, motion in the absence of a motion onset might also attract attention under certain circumstances.     

Repeated checking really does cause memory distrust

Memory phenomena associated with obsessive-compulsive disorder (OCD) have received increased attention in the recent literature. Some debate remains about whether OCD is characterized by deficits in memory per se, or by poor memory confidence. Following from a recent study that demonstrated memory distrust results from repeated checking of a virtual computerized stove, we asked 50 undergraduate students to repeatedly turn on, turn off and check either a real kitchen stove (relevant checking) or a real kitchen faucet (irrelevant checking) in a standardized, ritualized manner. All participants completed a final check of the stove following these 19 checking trials. Results indicated that following repeated relevant checking, participants reported significantly reduced memory confidence, vividness and detail. Repeated irrelevant checking did not produce these decreases. Results are discussed in terms of cognitive-behavioural formulations of OCD and in terms of the effects of repetition on memory and metamemory.     

Isoluminant motion onset captures attention

In their 2003 article, Abrams and Christ found that the onset of motion captured attention more effectively than either the offset of motion or continuous motion. Abrams and Christ conceptualized the capture to be occurring at a level higher than does detection of luminance changes in the stimulus. To examine this claim, in the present experiments we replicated their critical experiment but used isoluminant stimuli, which do not produce the low-level luminance transients typically associated with motion. Under isoluminant conditions, we found a pattern of results very similar to that found previously with luminance-defined stimuli, indicating that attention can be prioritized on the basis of perceived motion onset by an object in the absence of low-level luminance transients. This may reflect an evolutionary adaptation to bias attention toward objects that exhibit characteristics of animacy, such as abruptly changing from a static to a dynamic state.     

Salient stimuli capture attention and action

Reaction times in a visual search task increase when an irrelevant but salient stimulus is presented. Recently, the hypothesis that the increase in reaction times was due to attentional capture by the salient distractor has been disputed. We devised a task in which a search display was shown after observers had initiated a reaching movement toward a touch screen. In a display of vertical bars, observers had to touch the oblique target while ignoring a salient color singleton. Because the hand was moving when the display appeared, reach trajectories revealed the current selection for action. We observed that salient but irrelevant stimuli changed the reach trajectory at the same time as the target was selected, about 270 ms after movement onset. The change in direction was corrected after another 160 ms. In a second experiment, we compared manual selection of color and orientation targets and observed that selection occurred earlier for color than for orientation targets. Salient stimuli support faster selection than do less salient stimuli. Under the assumption that attentional selection for action and perception are based on a common mechanism, our results suggest that attention is indeed captured by salient stimuli.     

Moving and looming stimuli capture attention

Attention capture is often operationally defined as speeded search performance when an otherwise nonpredictive stimulus happens to be the target of a visual search. That is, if a stimulus captures attention, it should be searched with priority even when it is irrelevant to the task. Given this definition, only the abrupt appearance of a new object (see, e.g., Jonides & Yantis, 1988) and one type of luminance contrast change (Enns, Austen, Di Lollo, Rauschenberger, & Yantis, 2001) have been shown to strongly capture attention. We show that translating and looming stimuli also capture attention. This phenomenon does not occur for all dynamic events: We also show that receding stimuli do not attract attention. Although the sorts of dynamic events that capture attention do not fit neatly into a single category, we speculate that stimuli that signal potentially behaviorally urgent events are more likely to receive attentional priority.     

The influence of relevant and irrelevant stereoscopic depth cues: Depth information does not always capture attention

Previous research reported ambiguous findings regarding the relationship of visuospatial attention and (stereoscopic) depth information. Some studies indicate that attention can be focused on a distinct depth plane, while other investigations revealed attentional capture from irrelevant items located in other, unattended depth planes. To evaluate whether task relevance of depth information modulates the deployment of attentional resources across depth planes, the additional singleton paradigm was adapted: Singletons defined by depth (i.e., displayed behind or in front of a central depth plane) or color (green against gray) were presented among neutral items and served as targets or (irrelevant) distractors. When participants were instructed to search for a color target, no attentional capture from irrelevant depth distractors was observed. In contrast, it took substantially longer to search for depth targets when an irrelevant distractor was presented simultaneously. Color distractors as well as depth distractors caused attentional capture, independent of the distractors’ relative depth position (i.e., in front of or behind the target). However, slight differences in task performance were obtained depending on whether or not participants fixated within the target depth plane. Thus, the current findings indicate that attentional resources in general are uniformly distributed across different depth planes. Although task relevant depth singletons clearly affect the attentional system, this information might be processed subsequent to other stimulus features.     

Motion capture depends on signal strength

When flickering dots are superimposed onto a drifting grating, the dots appear to move coherently with the grating. In this study we examine: (i) how the perceived direction of a compound stimulus composed of superimposed grating and dots, moving in opposite directions with equal speeds, is influenced by the relative strength of the motion signals; (ii) how the perceived speed of a compound stimulus composed of superimposed grating and dots, moving in the same direction but at different speeds, is influenced by the relative strength of the motion signals; and (iii) whether this stimulus is discriminable from its metameric speed match. Dot signal strength was manipulated by using different proportions of signal dots in noise and different dot lifetimes. Both the perceived direction and speed of these compound stimuli depended upon the relative motion-signal strengths of the grating and the dots. Those compound stimuli that appeared coherent were not discriminable from the speed-matched metameric compound stimuli. When the signals were completely integrated into a coherent compound stimulus, the local motion signals were no longer perceptually available, though both contributed to the global percept. These data strongly support a weighted-combination model where the relative weights depend on signal strength, instead of a winner-takes-all model.     

Grouping does not require attention

Many theories of visual perception stipulate that Gestalt grouping occurs preattentively. Subjects' failure to report perceiving even salient grouping patterns under conditions of inattention challenges this assumption (see, e.g., Mack, Tang, Tuma, Kahn, & Rock, 1992), but Moore and Egeth (1997) showed that although subjects are indeed unable to identify grouping patterns outside the focus of attention, effects of these patterns on visual perception can be observed when they are assessed using implicit, rather than explicit, measures. However, this finding, which is the only one to date demonstrating grouping effects without attention, is open to an alternative account. In the present study, we eliminated this confound and replicated Moore and Egeth's findings, using the Müller-Lyer illusion (Experiments 1 and 2). Moreover, we found converging evidence for these findings with a variant of the flanker task (Experiment 3), when the amount of available attentional resources was varied (Experiments 4 and 5). The results reinforce the idea that, although grouping outside the focus of attention cannot be the object of overt report, grouping processes can occur without attention.     

Non-transient luminance changes do not capture attention

The processing of luminance change is a ubiquitous feature of the human visual system and provides the basis for the rapid orienting of attention to potentially important events (e.g., motion onset, object onset). However, despite its importance for attentional capture, it is not known whether a luminance change attracts attention solely because of its status as a sensory transient or can attract attention at a relatively high cognitive level. In a series of six experiments, we presented visual displays in which a single object underwent a luminance change that was either visible or obscured by a mask. A target then appeared either at the change location or elsewhere. The results showed that the luminance change attracted attention only in the visible condition. This was even observed with the largest change we could generate (> 75 cd/m(2)). These data suggest that the importance of a luminance change is only in its status as a low-level sensory transient.     

Bodies capture attention when nothing is expected

Functional neuroimaging research has shown that certain classes of visual stimulus selectively activate focal regions of visual cortex. Specifically, cortical areas that generally and selectively respond to faces (Kanwisher, N., McDermott, J., & Chun, M. M. (1997). The fusiform face area: a module in human extrastriate cortex specialized for face perception. Journal of Neuroscience, 17(11), 4302-4311; Puce, A., Allison, T., Asgari, M., Gore, J. C., & McCarthy, G. (1996). Differential sensitivity of human visual cortex to faces, letterstrings, and textures: a functional magnetic resonance imaging study. Journal of Neuroscience, 16(16), 5205-5215.) and to the human body (Downing, P. E., Jiang, Y., Shuman, M., & Kanwisher, N. (2001). A cortical area selective for visual processing of the human body. Science, 293(5539), 2470-2473.) have recently been described using fMRI. A parallel body of research has focused on the ability of faces to "capture" the focus of attention, compared to other kinds of objects (Lavie, N., Ro, T., & Russell, C. (2003). The role of perceptual load in processing distractor faces. Psychological Science, 14(5), 510-515; Ro, T., Russell, C., & Lavie, N. (2001). Changing faces: a detection advantage in the flicker paradigm. Psychological Science, 12(1), 94-99; Vuilleumier, P. (2000). Faces call for attention: evidence from patients with visual extinction. Neuropsychologia, 38(5), 693-700.). The present study uses Mack and Rock's "inattentional blindness" paradigm to investigate whether unexpected, task-irrelevant human body stimuli capture awareness when attention is occupied by a primary task (Mack, A., & Rock, I. (1998). Inattentional blindness. London: MIT Press). Silhouettes and stick figures of human bodies, and silhouettes of hands, were compared to control stimuli including object silhouettes, object stick figures, and scrambled silhouettes of bodies, body parts, and objects. Participants were significantly better able to detect a human figure relative to the control stimuli. These results suggest that the human body, like the face, may be prioritized for attentional selection. More generally, they are consistent with the proposal that the visual system assigns attentional priority to types of stimuli that are also represented in strongly selective cortical regions.     

Active suppression after involuntary capture of attention

After attention has been involuntarily captured by a distractor, how is it reoriented toward a target? One possibility is that attention to the distractor passively fades over time, allowing the target to become attended. Another possibility is that the captured location is actively suppressed so that attention can be directed toward the target location. The present study investigated this issue with event-related potentials (ERPs), focusing on the N2pc component (a neural measure of attentional deployment) and the Pd component (a neural measure of attentional suppression). Observers identified a color-defined target in a search array, which was preceded by a task-irrelevant cue array. When the cue array contained an item that matched the target color, this item captured attention (as measured both behaviorally and with the N2pc component). This capture of attention was followed by active suppression (indexed by the Pd component), and this was then followed by a reorienting of attention toward the target in the search array (indexed by the N2pc component). These findings indicate that the involuntary capture of attention by a distractor is followed by an active suppression process that presumably facilitates the subsequent voluntary orienting of attention to the target.     

Distractor interference in focused attention tasks is not mediated by attention capture

Distractor stimuli possessing information that is relevant for a task (henceforth, task-relevant distractors) often interfere with task performance. The interference by task-relevant distractors is observed even when distractors are positioned outside the main attentional focus. We investigated whether such interference is due to an attention capture by the distractors. Participants responded to a target colour while ignoring word distractors positioned within (Experiment 1) or outside (Experiments 2 and 3) the attentional focus. The words carried task-relevant information in their colour and personally significant information in their content. Because personally significant information affects performance only when positioned in an attended region, it was used as a marker for the locus of the attentional focus. As expected, when distractors were attended, both task-relevant and personally significant information affected performance. However, when distractors were unattended, only task-relevant information caused interference, suggesting that attention did not shift to the distractors’ location. We discuss possible accounts for interference effects in focused-attention tasks.     

Spatial attention does improve temporal discrimination

It has recently been stated that exogenous attention impairs temporal-resolution tasks (Hein, Rolke, & Ulrich, 2006; Rolke, Dinkelbach, Hein, & Ulrich, 2008; Yeshurun, 2004; Yeshurun & Levy, 2003). In comparisons of performance on spatially cued trials versus neutral cued trials, the results have suggested that spatial attention decreases temporal resolution. However, when performance on cued and uncued trials has been compared in order to equate for cue salience, typically speed—accuracy trade-offs (SATs) have been observed, making the interpretation of the results difficult. In the present experiments, we aimed at studying the effect of spatial attention in temporal resolution while using a procedure to control for SATs. We controlled reaction times (RTs) by constraining the time to respond, so that response decisions would be made within comparable time windows. The results revealed that when RT was controlled, performance was impaired for cued trials as compared with neutral trials, replicating previous findings. However, when cued and uncued trials were compared, performance was actually improved for cued trials as compared with uncued trials. These results suggest that SAT effects may have played an important role in the previous studies, because when they were controlled and measured, the results reversed, revealing that exogenous attention does improve performance on temporal-resolution tasks.     

It really just does not follow,comments on

I discuss points of agreement and disagreement with Francis (2013), and argue that the main lesson from his numerous one-off publication bias critiques is that developers of new statistical tools ought to anticipate their potential misuses and develop safeguards to prevent them.     

Voluntary allocation versus automatic capture of visual attention

Is there a difference in the kind of attention elicited by an abrupt-onset peripheral cue and that elicited by an instruction (e.g., a central arrow cue) to move attention to a peripheral location? In Experiment 1, we found that peripheral cues are no more effective in orienting attention than are central cues. No evidence was found for separable attentional systems consisting of a volitional response to central cues and an automatic response triggered only by peripheral cues. Rather, an identical or similar attentional process seems to be activated by either type of cue, although perhaps in different ways. Peripheral cues seem to have an automatic component, however, in that once attention is engaged by a peripheral cue, it cannot easily be disengaged for refocus elsewhere. In Experiment 2, after several sessions of practice, subjects were able to circumvent automatic attentional capture by an abrupt-onset peripheral cue and to volitionally redirect the focus of attention. Thus, attentional capture by abrupt-onset stimuli is not strongly automatic.