An effective attentional set for a specific colour does not prevent capture by infrequently presented motion distractors

An organism's survival depends on the ability to rapidly orient attention to unanticipated events in the world. Yet, the conditions needed to elicit such involuntary capture remain in doubt. Especially puzzling are spatial cueing experiments, which have consistently shown that involuntary shifts of attention to highly salient distractors are not determined by stimulus properties, but instead are contingent on attentional control settings induced by task demands. Do we always need to be set for an event to be captured by it, or is there a class of events that draw attention involuntarily even when unconnected to task goals? Recent results suggest that a task-irrelevant event will capture attention on first presentation, suggesting that salient stimuli that violate contextual expectations might automatically capture attention. Here, we investigated the role of contextual expectation by examining whether an irrelevant motion cue that was presented only rarely (～3–6% of trials) would capture attention when observers had an active set for a specific target colour. The motion cue had no effect when presented frequently, but when rare produced a pattern of interference consistent with attentional capture. The critical dependence on the frequency with which the irrelevant motion singleton was presented is consistent with early theories of involuntary orienting to novel stimuli. We suggest that attention will be captured by salient stimuli that violate expectations, whereas top-down goals appear to modulate capture by stimuli that broadly conform to contextual expectations.     

Effects of varying target luminance and cue luminance on attentional effects of spatial cues

Attentional effects of letter cues on target processing were investigated in a bilateral spatial cueing paradigm. Luminance contrast of the cue stimuli and of the target stimuli were both manipulated. Consistent with predictions derived from theoretical models of visual attention, manipulating cue luminance and target luminance had very different effects on performance. In agreement with the dorsal stream attention hypothesis (Marrett et al., 2011) orienting effects were unaffected by changes in cue luminance; but in agreement with the work of Reynolds, Pasternak, and Desimone (2000) and Carrasco, Ling, and Read (2004) orienting effects were strongly modulated by changes in the luminance and perceptual quality of the target. Theoretical implications of the results are considered and the data are explained in terms of a sensory enhancement effect, whereby attention amplifies the neuronal responses for attended stimuli.     

Processing spatial relations with different apertures of attention

Neuropsychological studies suggest the existence of lateralized networks that represent categorical and coordinate types of spatial information. In addition, studies with neural networks have shown that they encode more effectively categorical spatial judgments or coordinate spatial judgments, if their input is based, respectively, on units with relatively small, nonoverlapping receptive fields, as opposed to units with relatively large, overlapping receptive fields. These findings leave open the question of whether interactive processes between spatial detectors and types of spatial relations can be modulated by spatial attention. We hypothesized that spreading the attention window to encompass an area that includes two objects promotes coordinate spatial relations, based on coarse coding by large, overlapping, receptive fields. In contrast, narrowing attention to encompass an area that includes only one of the objects benefits categorical spatial relations, by effectively parsing space. By use of a cueing procedure, the spatial attention window was manipulated to select regions of differing areas. As predicted, when the attention window was large, coordinate spatial transformations were noticed faster than categorical transformations; in contrast, when the attention window was relatively smaller, categorical spatial transformations were noticed faster than coordinate transformations. Another novel finding was that coordinate changes were noticed faster when cueing an area that included both objects as well as the empty space between them than when simultaneously cueing both areas including the objects while leaving the gap between them uncued.     

The role of spatial attention and other processes on the magnitude and time course of cueing effects

We are quite often exposed to multiple objects present in the visual scene, thus attentional selection is necessary in order to selectively respond to the relevant information. Objects can be selected on the basis of the location they occupy by orienting attention in space. In this paper, we review the evidence showing that attention can be oriented in space either endogenously, on the basis of central cues, predictive of the relevant location, or exogenously, automatically triggered by the salient properties of visual stimuli (peripheral cues). Several dissociations observed between orienting on the basis of the two types of cues have led to the conclusion that they do not represent just two modes of triggering the orienting of the very same attentional mechanism, but rather they modulate processing differently. We present a theoretical framework according to which endogenous predictive cues facilitate target processing by orienting attention, thus amplifying processing at the attended location. In contrast, apart from attentional orienting, peripherally presented discrepant cues might trigger additional cue-target event-integration and event-segregation processes, which modulate processing in a different way, thus leading to cueing effects that are exclusively triggered by peripheral cues.     

Salience-based progression of visual attention: Time course

In a visual search task, visual attention progresses from the most to the least salient item until a target is found. The time course of such salience-based progression remains unclear although the temporal deployment seems as crucial as the spatial deployment. The present study investigated how the general hierarchical pattern takes place. Healthy volunteers were presented with a primed visual search paradigm in which the primes consisted of three items differing in salience for either 33, 50 or 100 ms. Subsequently one of them became the target and participants had to make a judgment about it. In order to progress on the basis of salience, attention seemed first to be captured by the most salient item. Secondly, the first two most salient items seemed both encompassed within the attentional spotlight. At that time, the least salient item seemed inhibited, completing the stepwise progression of attention. In summary, our data suggest that the hierarchical pattern is built up over time through orienting and expansion of the spotlight, and inhibition of the least salient signals. Furthermore, complementary analyses revealed a proximity effect influencing the selection of the next location to visit. As predicted by different computational models, items located closely to the first visited location were more prone to attract attention than distant items but interestingly enough, this effect only applied to the least salient item suggesting a balance between salience and proximity criteria. Critically also, salience and proximity effects seem to have different time courses. Results are only partially explained by current visual attention models and require further investigation.     

Rapid allocation of temporal attention in the attentional blink paradigm

How fast can information of a first target (T1) in a rapid serial visual presentation be used for top-down allocation of attention in time? A valid cue about the temporal position of a second target (T2) was integrated into T1. The data show that 100 ms after T1 onset, T2 was identified better than without cue, raising the conditional T2 performance. T1 apparently triggers a facilitative effect of attention, known from other paradigms such as peripheral cueing.     

Modulation of spatial Stroop by object-based attention but not by space-based attention

Earlier studies have shown that the spatial Stroop effect systematically decreases when a peripheral precue is presented at the same location as the target, compared to an uncued location condition. In this study, two experiments were conducted to explore whether the cueing modulation of spatial Stroop is object based and/or space based. In Experiment 1, we found evidence favouring the view that the cueing modulation of the spatial Stroop effect is entirely object based, as no differences were found in conflict reduction for the same-location and same-object conditions. In Experiment 2, the cue was predictive, and a similar object-based modulation of spatial Stroop was still observed. However, the direction of such modulation was affected by the rectangles' orientation. Overall, the pattern of results obtained favours the object-integration (Lupiáñez & Milliken, 1999; Lupiáñez, Milliken, Solano, Weaver, & Tipper, 2001) and referential-coding accounts (Danziger, Kingstone, & Ward, 2001) and seems to provide evidence against the attention-shift account (Rubichi, Nicoletti, Iani, & Umilta, 1997; Stoffer, 1991).     

Attentional sets influence perceptual load effects,but not dilution effects

Perceptual load theory [Lavie, N. (1995). Perceptual load as a necessary condition for selective attention. Journal of Experimental Psychology: Human Perception and Performance, 21, 451–468.; Lavie, N., & Tsal, Y. (1994) Perceptual load as a major determinant of the locus of selection in visual attention. Perception & Psychophysics, 56, 183–197.] proposes that interference from distractors can only be avoided in situations of high perceptual load. This theory has been supported by blocked design manipulations separating low load (when the target appears alone) and high load (when the target is embedded among neutral letters). Tsal and Benoni [(2010a). Diluting the burden of load: Perceptual load effects are simply dilution effects. Journal of Experimental Psychology: Human Perception and Performance, 36, 1645–1656.; Benoni, H., & Tsal, Y. (2010). Where have we gone wrong? Perceptual load does not affect selective attention. Vision Research, 50, 1292–1298.] have recently shown that these manipulations confound perceptual load with “dilution” (the mere presence of additional heterogeneous items in high-load situations). Theeuwes, Kramer, and Belopolsky [(2004). Attentional set interacts with perceptual load in visual search. Psychonomic Bulletin & Review, 11, 697–702.] independently questioned load theory by suggesting that attentional sets might also affect distractor interference. When high load and low load were intermixed, and participants could not prepare for the presentation that followed, both the low-load and high-load trials showed distractor interference. This result may also challenge the dilution account, which proposes a stimulus-driven mechanism. In the current study, we presented subjects with both fixed and mixed blocks, including a mix of dilution trials with low-load trials and with high-load trials. We thus separated the effect of dilution from load and tested the influence of attentional sets on each component. The results revealed that whereas perceptual load effects are influenced by attentional sets, the dilution component is not. This strengthens the notion that dilution is a stimulus-driven mechanism, which enables effective selectivity.     

No two cues are alike: Depth of learning during infancy is dependent on what orients attention

Human infants develop a variety of attentional mechanisms that allow them to extract relevant information from a cluttered multimodal world. We know that both social and nonsocial cues shift infants’ attention, but not how these cues differentially affect learning of multimodal events. Experiment 1 used social cues to direct 8- and 4-month-olds’ attention to two audiovisual events (i.e., animations of a cat or dog accompanied by particular sounds) while identical distractor events played in another location. Experiment 2 directed 8-month-olds’ attention with colorful flashes to the same events. Experiment 3 measured baseline learning without attention cues both with the familiarization and test trials (no cue condition) and with only the test trials (test control condition). The 8-month-olds exposed to social cues showed specific learning of audiovisual events. The 4-month-olds displayed only general spatial learning from social cues, suggesting that specific learning of audiovisual events from social cues may be a function of experience. Infants cued with the colorful flashes looked indiscriminately to both cued locations during test (similar to the 4-month-olds learning from social cues) despite attending for equal duration to the training trials as the 8-month-olds with the social cues. Results from Experiment 3 indicated that the learning effects in Experiments 1 and 2 resulted from exposure to the different cues and multimodal events. We discuss these findings in terms of the perceptual differences and relevance of the cues.     

Going the distance: Extra-symbolic contributions to the symbolic control of spatial attention

Over the past 30 years, researchers have used symbolic cues such as spatial words and arrows to direct observers' attention to the location of target objects that appear at a single, fixed distance in simple visual environments; however, they have done so by using symbolic cues that provide only partial—directional—information about the spatial location of target objects. Thus, it remains unclear whether observers can only shift their attention broadly in the cued direction in response to these cues or whether they can shift their attention to the specific location of the target by combining an expectation about direction (derived from apprehension of the directional cue) with an expectation about distance (derived from some extra-symbolic cue). The results of two experiments showed that observers do shift their attention to relatively coarse spatial locations by combining expectancies about direction and distance, and that the extent to which observers do so is modulated by the presence of visible markers and the expected distance of the target. These findings are important because they provide the first evidence that extra-symbolic information about distance contributes to the symbolic control of spatial attention.     

Components of attentional bias to threat in high trait anxiety: Facilitated engagement, impaired disengagement, and attentional avoidance

There is a wealth of evidence demonstrating enhanced attention to threat in high trait anxious individuals (HTA) compared with low trait anxious individuals (LTA). In two experiments, we investigated whether this attentional bias is related to facilitated attentional engagement to threat or difficulties disengaging attention from threat. HTA and LTA undergraduates performed a modified exogenous cueing task, in which the location of a target was correctly or incorrectly cued by neutral, highly and mildly threatening pictures. Results indicate that at 100 ms picture presentation, HTA individuals more strongly engaged their attention with and showed impaired disengagement from highly threatening pictures than LTA individuals. In addition, HTA individuals showed a stronger tendency to attentional avoidance of threat at the 200 and 500 ms picture presentation. These data provide evidence for differential patterns of anxiety-related biases in attentive processing of threat at early versus later stages of information processing.     

Assessing the impact of verbal and visuospatial working memory load on eye-gaze cueing

Observers tend to respond more quickly to peripheral stimuli that are being gazed at by a centrally presented face, than to stimuli that are not being gazed at. While this gaze-cueing effect was initially seen as reflexive, there have also been some indications that top-down control processes may be involved. Therefore, the present investigation employed a dual-task paradigm to attempt to disrupt the putative control processes involved in gaze cueing. Two experiments examined the impact of working memory load on gaze cueing. In Experiment 1, participants were required to hold a set of digits in working memory during each gaze trial. In Experiment 2, the gaze task was combined with an auditory task that required the manipulation and maintenance of visuospatial information. Gaze cueing effects were observed, but they were not modulated by dual-task load in either experiment. These results are consistent with traditional accounts of gaze cueing as a highly reflexive process.     

Grounding spatial language in the motor system: Reciprocal interactions between spatial semantics and orienting

Shifts of attention that are directed by spatial words are thought to be mediated by a spatial frame of reference. Previous studies have documented a selection cost when visual attention is directed along the left/right axis relative to the above/below axis due to the greater ambiguity of the horizontal endpoints. The present study investigated whether the horizontal endpoints may be more fully disambiguated when “left/right” cues are first enacted by nondivisible, more discrete, modes of orienting such as directional motor responses. This issue was investigated using a repetition priming paradigm in which the effects of prior enactments were measured on the subsequent conceptual control of visual attention. The results of four experiments showed that grounding spatial language in the motor system can enhance the focus of visual attention by disambiguating the endpoints of the horizontal axis. In so doing, the present study extends previous research demonstrating that spatial concepts can influence the spatial distribution of attention by demonstrating that different modes of orienting can also influence the semantics of space. Implications for the premotor theory of attention and grounded theories of cognition are also discussed.     

A configural dominant account of contextual cueing: Configural cues are stronger than colour cues

Previous work has shown that reaction times to find a target in displays that have been repeated are faster than those for displays that have never been seen before. This learning effect, termed “contextual cueing” (CC), has been shown using contexts such as the configuration of the distractors in the display and the background colour. However, it is not clear how these two contexts interact to facilitate search. We investigated this here by comparing the strengths of these two cues when they appeared together. In Experiment 1, participants searched for a target that was cued by both colour and distractor configural cues, compared with when the target was only predicted by configural information. The results showed that the addition of a colour cue did not increase contextual cueing. In Experiment 2, participants searched for a target that was cued by both colour and distractor configuration compared with when the target was only cued by colour. The results showed that adding a predictive configural cue led to a stronger CC benefit. Experiments 3 and 4 tested the disruptive effects of removing either a learned colour cue or a learned configural cue and whether there was cue competition when colour and configural cues were presented together. Removing the configural cue was more disruptive to CC than removing colour, and configural learning was shown to overshadow the learning of colour cues. The data support a configural dominant account of CC, where configural cues act as the stronger cue in comparison to colour when they are presented together.     

Toddlers' language-mediated visual search: They need not have the words for it

Eye movements made by listeners during language-mediated visual search reveal a strong link between visual processing and conceptual processing. For example, upon hearing the word for a missing referent with a characteristic colour (e.g., “strawberry”), listeners tend to fixate a colour-matched distractor (e.g., a red plane) more than a colour-mismatched distractor (e.g., a yellow plane). We ask whether these shifts in visual attention are mediated by the retrieval of lexically stored colour labels. Do children who do not yet possess verbal labels for the colour attribute that spoken and viewed objects have in common exhibit language-mediated eye movements like those made by older children and adults? That is, do toddlers look at a red plane when hearing “strawberry”? We observed that 24-month-olds lacking colour term knowledge nonetheless recognized the perceptual–conceptual commonality between named and seen objects. This indicates that language-mediated visual search need not depend on stored labels for concepts.     

Altering attentional control settings causes persistent biases of visual attention

Attentional control settings have an important role in guiding visual behaviour. Previous work within cognitive psychology has found that the deployment of general attentional control settings can be modulated by training. However, research has not yet established whether long-term modifications of one particular type of attentional control setting can be induced. To address this, we investigated persistent alterations to feature search mode, also known as an attentional bias, towards an arbitrary stimulus in healthy participants. Subjects were biased towards the colour green by an information sheet. Attentional bias was assessed using a change detection task. After an interval of either 1 or 2 weeks, participants were then retested on the same change detection task, tested on a different change detection task where colour was irrelevant, or were biased towards an alternative colour. One experiment included trials in which the distractor stimuli (but never the target stimuli) were green. The key finding was that green stimuli in the second task attracted attention, despite this impairing task performance. Furthermore, inducing a second attentional bias did not override the initial bias toward green objects. The attentional bias also persisted for at least two weeks. It is argued that this persistent attentional bias is mediated by a chronic change to participants’ attentional control settings, which is aided by long-term representations involving contextual cueing. We speculate that similar changes to attentional control settings and continuous cueing may relate to attentional biases observed in psychopathologies. Targeting these biases may be a productive approach to treatment.     

Equally attending but still not seeing: An eye-tracking study of change detection in own- and other-race faces

The present study aimed to investigate whether the faster change detection in own-race faces in a change blindness paradigm, reported by Humphreys, Hodsoll, and Campbell (2005) and explained in terms of people's poorer ability to discriminate other-race faces, may be explained by people's preferential attention towards own-race faces. The study by Humphreys et al. was replicated using the same stimuli, while participants’ eye movements were recorded. These revealed that there was no attentional bias towards own-race faces (analysed in terms of fixation order, number, and duration), but people still detected changes in own-race faces faster than in other-race faces. The current results therefore give further support for the original claim that people are less sensitive to changes made in other-race faces, when own and other-race faces are equally attended.     

Observation of another's action but not eye gaze triggers allocentric visual perspective

In the present paper, we investigated whether observation of bodily cues—that is, hand action and eye gaze—can modulate the onlooker's visual perspective taking. Participants were presented with scenes of an actor gazing at an object (or straight ahead) and grasping an object (or not) in a 2?×?2 factorial design and a control condition with no actor in the scene. In Experiment 1, two groups of subjects were explicitly required to judge the left/right location of the target from their own (egocentric group) or the actor's (allocentric group) point of view, whereas in Experiment 2 participants did not receive any instruction on the point of view to assume. In both experiments, allocentric coding (i.e., the actor's point of view) was triggered when the actor grasped the target, but not when he gazed towards it, or when he adopted a neutral posture. In Experiment 3, we demonstrate that the actor's gaze but not action affected participants' attention orienting. The different effects of others' grasping and eye gaze on observers' behaviour demonstrated that specific bodily cues convey distinctive information about other people's intentions.     

The coupling between spatial attention and other components of task-set: A task-switching investigation

Is spatial attention reconfigured independently of, or in tandem with, other task-set components when the task changes? We tracked the eyes of participants cued to perform one of three digit-classification tasks, each consistently associated with a distinct location. Previously we observed, on task switch trials, a substantial delay in orientation to the task-relevant location and tendency to fixate the location of the previously relevant task—“attentional inertia”. In the present experiments the cues specified (and instructions emphasized) the relevant location rather than the current task. In Experiment 1, with explicit spatial cues (arrows or spatial adverbs), the previously documented attentional handicaps all but disappeared, whilst the performance “switch cost” increased. Hence, attention can become decoupled from other aspects of task-set, but at a cost to the efficacy of task-set preparation. Experiment 2 used arbitrary single-letter cues with instructions and a training regime that encouraged participants to interpret the cue as indicating the relevant location rather than task. As in our previous experiments, and unlike in Experiment 1, we now observed clear switch-induced attentional delay and inertia, suggesting that the natural tendency is for spatial attention and task-set to be coupled and that only quasi-exogenous location cues decouple their reconfiguration.     

Spatial Correspondence Learning is Critical for the Sequence Effects of Symbolic Cueing

Attention orienting has been found to be influenced by the previous cueing status in a spatial cueing paradigm. The purpose of this study was to determine whether the cue predictive values or the spatial correspondence learning between cues and targets could influence the sequence effect of symbolic cueing. The findings revealed that the predictive values of arrow or word cues do not lead to different sequence effects, but that visually asymmetrical letter cues, which allow spatial correspondence learning between cues and targets, induce stronger sequence effects than visually symmetrical letter cues. In addition, visually symmetrical directional word cues can induce sequence effects. The results suggest that spatial correspondence learning, although not obligatory, is critical for the sequence effects of symbolic cueing. The findings support the feature‐integration hypothesis, rather than the strategic adjustments account.