Spatial distribution of attentional bias in visuo-spatial working memory following multiple cues

When attention is focused on one location, its spatial distribution depends on many factors, such as the distance between the attended location and the target location, the presence of visual meridians in between them, and the way, endogenous or exogenous, by which attention is oriented. However, it is not well known how attention distributes when more than one location is endogenously or exogenously cued, which was the focus of the current study. Furthermore, the distribution of attention has been manly investigated in perception. In the present study we faced this issue from a different perspective, by examining the spatial distribution of the attentional bias in visuo-spatial working memory (VSWM), when attention is oriented either exogenously or endogenously, i.e., after two peripheral vs. central symbolic cues (also manipulating cue–target predictability). Results indicated a systematic difference between endogenous and exogenous attention regarding the distribution of the attentional bias over VSWM. In fact, attentional bias following endogenous cues was affected by the presence of visual meridians and by the split of the attentional focus, converging in a unipolar attentional distribution, independently of cue–target predictability. On the other hand, when pulled by exogenous cues, attention distributed uni-modally or multi-modally depending on the distance between the cued locations, with larger effects for highly predictive cues. Results are discussed in terms of space-based, object-based and perceptual grouping mechanisms.     

Exogenous and endogenous spatial attention effects on visuospatial working memory

In this study, we investigate how exogenous and endogenous orienting of spatial attention affect visuospatial working memory (VSWM). Specifically, we focused on two attentional effects and their consequences on storage in VSWM, when exogenous (Experiment 1) or endogenous (Experiment 2) orienting cues were used. The first effect, known as the meridian effect, is given by a decrement in behavioural performance when spatial cues and targets are presented in locations separated by vertical and/or horizontal meridians. The second effect, known as the distance effect, is given by a decrement in the orienting effects as a function of the spatial distance between cues and targets. Our results revealed a dissociation between exogenous and endogenous orienting mechanisms in terms of both meridian and distance effects. We found that meridian crossing affects performance only when endogenous cues were used. Specifically, VSWM performance with endogenous cueing depended more on the number of meridian crossings than on distance between cue and target. By contrast, a U-shaped distance dependency was observed using exogenous cues. Our findings therefore suggest that exogenous and endogenous orienting mechanisms lead to different forms of attentional bias for storage in VSWM.     

Modulation of auditory spatial attention by visual emotional cues: differential effects of attentional engagement and disengagement for pleasant and unpleasant cues

Previous research has demonstrated that threatening, compared to neutral pictures, can bias attention towards non-emotional auditory targets. Here we investigated which subcomponents of attention contributed to the influence of emotional visual stimuli on auditory spatial attention. Participants indicated the location of an auditory target, after brief (250 ms) presentation of a spatially non-predictive peripheral visual cue. Responses to targets were faster at the location of the preceding visual cue, compared to at the opposite location (cue validity effect). The cue validity effect was larger for targets following pleasant and unpleasant cues compared to neutral cues, for right-sided targets. For unpleasant cues, the crossmodal cue validity effect was driven by delayed attentional disengagement, and for pleasant cues, it was driven by enhanced engagement. We conclude that both pleasant and unpleasant visual cues influence the distribution of attention across modalities and that the associated attentional mechanisms depend on the valence of the visual cue.     

Gender differences in spatial perception of body tilt

The tendency for observers to overestimate slant is not simply a visual illusion but can also occur with another sense, such as proprioception, as in the case of overestimation of self-body tilt. In the present study, distortion in the perception of body tilt was examined as a function of gender and multisensory spatial information. We used a full-body-tilt apparatus to test when participants experienced being tilted by 45 degrees, with visual and auditory cues present or absent. Body tilt was overestimated in all conditions, with the largest bias occurring when there were no visual or auditory cues. Both visual and auditory information independently improved performance. We also found a gender difference, with women exhibiting more bias in the absence of auditory information and more improvement when auditory information was added. The findings support the view that perception of body tilt is multisensory and that women more strongly utilize auditory information in such multisensory spatial judgments.     

内外源性空间注意对多感觉整合的影响

本文采用内-外源性空间线索靶子范式, 操控内源性线索有效性(有效线索、无效线索)、外源性线索有效性(有效线索、无效线索)、目标刺激类型(视觉刺激、听觉刺激、视听觉刺激)三个自变量。通过两个不同任务难度的实验(实验1: 简单定位任务; 实验2: 复杂辨别任务)来考察内外源性空间注意对多感觉整合的影响。两个实验结果均发现外源性空间注意显著减弱了多感觉整合效应, 内源性空间注意没有显著增强多感觉整合效应; 实验2中还发现了内源性空间注意会对外源性空间注意减弱多感觉整合效应产生影响。结果表明, 与内源性空间注意不同, 外源性空间注意对多感觉整合的影响不易受任务难度的调控; 当任务较难时内源性空间注意会影响外源性空间注意减弱多感觉整合效应的过程。由此推测, 内外源性空间注意对多感觉整合的调节并非彼此独立、而是相互影响的。     

Capturing spatial attention with multisensory cues

We assessed the influence of multisensory interactions on the exogenous orienting of spatial attention by comparing the ability of auditory, tactile, and audiotactile exogenous cues to capture visuospatial attention under conditions of no perceptual load versus high perceptual load. In Experiment 1, participants discriminated the elevation of visual targets preceded by either unimodal or bimodal cues under conditions of either a high perceptual load (involving the monitoring of a rapidly presented central stream of visual letters for occasionally presented target digits) or no perceptual load (when the central stream was replaced by a fixation point). All of the cues captured spatial attention in the no-load condition, whereas only the bimodal cues captured visuospatial attention in the highload condition. In Experiment 2, we ruled out the possibility that the presentation of any changing stimulus at fixation (i.e., a passively monitored stream of letters) would eliminate exogenous orienting, which instead appears to be a consequence of high perceptual load conditions (Experiment 1). These results demonstrate that multisensory cues capture spatial attention more effectively than unimodal cues under conditions of concurrent perceptual load.     

Cross-modal associations between vision, touch, and audition influence visual search through top-down attention, not bottom-up capture

Recently, Guzman-Martinez, Ortega, Grabowecky, Mossbridge, and Suzuki (Current Biology : CB, 22(5), 383–388, 2012) reported that observers could systematically match auditory amplitude modulations and tactile amplitude modulations to visual spatial frequencies, proposing that these cross-modal matches produced automatic attentional effects. Using a series of visual search tasks, we investigated whether informative auditory, tactile, or bimodal cues can guide attention toward a visual Gabor of matched spatial frequency (among others with different spatial frequencies). These cues improved visual search for some but not all frequencies. Auditory cues improved search only for the lowest and highest spatial frequencies, whereas tactile cues were more effective and frequency specific, although less effective than visual cues. Importantly, although tactile cues could produce efficient search when informative, they had no effect when uninformative. This suggests that cross-modal frequency matching occurs at a cognitive rather than sensory level and, therefore, influences visual search through voluntary, goal-directed behavior, rather than automatic attentional capture.     

集中和分散注意对多感觉整合中听觉主导效应的影响

听觉主导效应是指多感觉通道信息整合过程中,听觉通道中的信息得到优先加工,从而主导其他感觉通道的信息。研究采用经典的声音诱发闪光错觉的范式,通过两个实验操纵了注意资源的分配方式以及实验任务难度,考察了主动注意听觉通道的声音刺激对声音诱发闪光错觉产生的影响,以及任务难度对声音诱发闪光错觉的影响。结果发现:(1)裂变错觉会受到注意资源分配程度的影响,但是融合错觉则不然;(2)任务难度既不会影响裂变错觉,也不会影响融合错觉。说明了分散注意能够影响听觉主导效应中的裂变错觉,并且这种主导效应与任务难度无关。     

Spatial attention and audiovisual interactions in apparent motion

In this study, the authors combined the cross-modal dynamic capture task (involving the horizontal apparent movement of visual and auditory stimuli) with spatial cuing in the vertical dimension to investigate the role of spatial attention in cross-modal interactions during motion perception. Spatial attention was manipulated endogenously, either by means of a blocked design or by predictive peripheral cues, and exogenously by means of nonpredictive peripheral cues. The results of 3 experiments demonstrate a reduction in the magnitude of the cross-modal dynamic capture effect on cued trials compared with uncued trials. The introduction of neutral cues (Experiments 4 and 5) confirmed the existence of both attentional costs and benefits. This attention-related reduction in cross-modal dynamic capture was larger when a peripheral cue was used compared with when attention was oriented in a purely endogenous manner. In sum, the results suggest that spatial attention reduces illusory binding by facilitating the segregation of unimodal signals, thereby modulating audiovisual interactions in information processing. Thus, the effect of spatial attention occurs prior to or at the same time as cross-modal interactions involving motion information.     

On the interplay of visuospatial and audiotemporal dominance: Evidence from a multimodal kappa effect

When participants judge multimodal audiovisual stimuli, the auditory information strongly dominates temporal judgments, whereas the visual information dominates spatial judgments. However, temporal judgments are not independent of spatial features. For example, in the kappa effect, the time interval between two marker stimuli appears longer when they originate from spatially distant sources rather than from the same source. We investigated the kappa effect for auditory markers presented with accompanying irrelevant visual stimuli. The spatial sources of the markers were varied such that they were either congruent or incongruent across modalities. In two experiments, we demonstrated that the spatial layout of the visual stimuli affected perceived auditory interval duration. This effect occurred although the visual stimuli were designated to be task-irrelevant for the duration reproduction task in Experiment 1, and even when the visual stimuli did not contain sufficient temporal information to perform a two-interval comparison task in Experiment 2. We conclude that the visual and auditory marker stimuli were integrated into a combined multisensory percept containing temporal as well as task-irrelevant spatial aspects of the stimulation. Through this multisensory integration process, visuospatial information affected even temporal judgments, which are typically dominated by the auditory modality.     

Multisensory cues capture spatial attention regardless of perceptual load

We compared the ability of auditory, visual, and audiovisual (bimodal) exogenous cues to capture visuo-spatial attention under conditions of no load versus high perceptual load. Participants had to discriminate the elevation (up vs. down) of visual targets preceded by either unimodal or bimodal cues under conditions of high perceptual load (in which they had to monitor a rapidly presented central stream of visual letters for occasionally presented target digits) or no perceptual load (in which the central stream was replaced by a fixation point). The results of 3 experiments showed that all 3 cues captured visuo-spatial attention in the no-load condition. By contrast, only the bimodal cues captured visuo-spatial attention in the high-load condition, indicating for the first time that multisensory integration can play a key role in disengaging spatial attention from a concurrent perceptually demanding stimulus.     

Attentional orienting across the sensory modalities

This event-related potential study investigated (i) to what extent incongruence between attention-directing cue and cued target modality affects attentional control processes that bias the system in advance to favor a particular stimulus modality and (ii) to what extent top-down attentional control mechanisms are generalized for the type of information that is to be attended. To this end, both visual and auditory word cues were used to instruct participants to direct attention to a specific visual (color) or auditory (pitch) stimulus feature of a forthcoming multisensory target stimulus. Effects of cue congruency were observed within 200 ms post-cue over frontal scalp regions and related to processes involved in shifting attention from the cue modality to the modality of the task-relevant target feature. Both directing visual attention and directing auditory attention were associated with dorsal posterior positivity, followed by sustained fronto-central negativity. However, this fronto-central negativity appeared to have an earlier onset and was more pronounced when the visual modality was cued. Together the present results suggest that the mechanisms involved in deploying attention are to some extent determined by the modality (visual, auditory) in which attention operates, and in addition, that some of these mechanisms can also be affected by cue congruency.     

内源性注意与外源性注意的跨通道比较

该研究利用空间线索技术的实验模式,考察跨视觉和听觉通道的内源性选择注意与外源性选择性注意的相互关系。实验结果表明：(1)听觉中央线索在较长的SOA(至少500毫秒)条件下,可以引导内源性空间选择性注意;同时外周线索突现也能自动化地吸引部分注意资源。(2)听觉和视觉选择注意是分离的加工通道,但二者之间存在相互联系。     

Improving visual spatial working memory in younger and older adults: effects of cross-modal cues

Spatially informative auditory and vibrotactile (cross-modal) cues can facilitate attention but little is known about how similar cues influence visual spatial working memory (WM) across the adult lifespan. We investigated the effects of cues (spatially informative or alerting pre-cues vs. no cues), cue modality (auditory vs. vibrotactile vs. visual), memory array size (four vs. six items), and maintenance delay (900 vs. 1800 ms) on visual spatial location WM recognition accuracy in younger adults (YA) and older adults (OA). We observed a significant interaction between spatially informative pre-cue type, array size, and delay. OA and YA benefitted equally from spatially informative pre-cues, suggesting that attentional orienting prior to WM encoding, regardless of cue modality, is preserved with age. Contrary to predictions, alerting pre-cues generally impaired performance in both age groups, suggesting that maintaining a vigilant state of arousal by facilitating the alerting attention system does not help visual spatial location WM.     

Is the exogenous orienting of spatial attention truly automatic? Evidence from unimodal and multisensory studies

The last decade has seen great progress in the study of the nature of crossmodal links in exogenous and endogenous spatial attention (see [Spence, C., McDonald, J., & Driver, J. (2004). Exogenous spatial cuing studies of human crossmodal attention and multisensory integration. In C. Spence, & J. Driver (Eds.), Crossmodal space and crossmodal attention (pp. 277-320). Oxford, UK: Oxford University Press.], for a recent review). A growing body of research now highlights the existence of robust crossmodal links between auditory, visual, and tactile spatial attention. However, until recently, studies of exogenous and endogenous attention have proceeded relatively independently. In daily life, however, these two forms of attentional orienting continuously compete for the control of our attentional resources, and ultimately, our awareness. It is therefore critical to try and understand how exogenous and endogenous attention interact in both the unimodal context of the laboratory and the multisensory contexts that are more representative of everyday life. To date, progress in understanding the interaction between these two forms of orienting has primarily come from unimodal studies of visual attention. We therefore start by summarizing what has been learned from this large body of empirical research, before going on to review more recent studies that have started to investigate the interaction between endogenous and exogenous orienting in a multisensory setting. We also discuss the evidence suggesting that exogenous spatial orienting is not truly automatic, at least when assessed in a crossmodal context. Several possible models describing the interaction between endogenous and exogenous orienting are outlined and then evaluated in terms of the extant data.     

Crossmodal attention switching: Auditory dominance in temporal discrimination tasks

Visual stimuli are often processed more efficiently than accompanying stimuli in another modality. In line with this “visual dominance”, earlier studies on attentional switching showed a clear benefit for visual stimuli in a bimodal visual–auditory modality-switch paradigm that required spatial stimulus localization in the relevant modality. The present study aimed to examine the generality of this visual dominance effect. The modality appropriateness hypothesis proposes that stimuli in different modalities are differentially effectively processed depending on the task dimension, so that processing of visual stimuli is favored in the dimension of space, whereas processing auditory stimuli is favored in the dimension of time. In the present study, we examined this proposition by using a temporal duration judgment in a bimodal visual–auditory switching paradigm. Two experiments demonstrated that crossmodal interference (i.e., temporal stimulus congruence) was larger for visual stimuli than for auditory stimuli, suggesting auditory dominance when performing temporal judgment tasks. However, attention switch costs were larger for the auditory modality than for visual modality, indicating a dissociation of the mechanisms underlying crossmodal competition in stimulus processing and modality-specific biasing of attentional set.     

Auditory cueing facilitates temporospatial accuracy of sequential movements

Effectively executing goal-directed behaviours requires both temporal and spatial accuracy. Previous work has shown that providing auditory cues enhances the timing of upper-limb movements. Interestingly, alternate work has shown beneficial effects of multisensory cueing (i.e., combined audiovisual) on temporospatial motor control. As a result, it is not clear whether adding visual to auditory cues can enhance the temporospatial control of sequential upper-limb movements specifically. The present study utilized a sequential pointing task to investigate the effects of auditory, visual, and audiovisual cueing on temporospatial errors. Eighteen participants performed pointing movements to five targets representing short, intermediate, and large movement amplitudes. Five isochronous auditory, visual, or audiovisual priming cues were provided to specify an equal movement duration for all amplitudes prior to movement onset. Movement time errors were then computed as the difference between actual and predicted movement times specified by the sensory cues, yielding delta movement time errors (ΔMTE). It was hypothesized that auditory-based (i.e., auditory and audiovisual) cueing would yield lower movement time errors compared to visual cueing. The results showed that providing auditory relative to visual priming cues alone reduced ΔMTE particularly for intermediate amplitude movements. The results further highlighted the beneficial impact of unimodal auditory cueing for improving visuomotor control in the absence of significant effects for the multisensory audiovisual condition.     

Multisensory-mediated auditory localization

Multisensory integration is a powerful mechanism for maximizing sensitivity to sensory events. We examined its effects on auditory localization in healthy human subjects. The specific objective was to test whether the relative intensity and location of a seemingly irrelevant visual stimulus would influence auditory localization in accordance with the inverse effectiveness and spatial rules of multisensory integration that have been developed from neurophysiological studies with animals [Stein and Meredith, 1993 The Merging of the Senses (Cambridge, MA: MIT Press)]. Subjects were asked to localize a sound in one condition in which a neutral visual stimulus was either above threshold (supra-threshold) or at threshold. In both cases the spatial disparity of the visual and auditory stimuli was systematically varied. The results reveal that stimulus salience is a critical factor in determining the effect of a neutral visual cue on auditory localization. Visual bias and, hence, perceptual translocation of the auditory stimulus appeared when the visual stimulus was supra-threshold, regardless of its location. However, this was not the case when the visual stimulus was at threshold. In this case, the influence of the visual cue was apparent only when the two cues were spatially coincident and resulted in an enhancement of stimulus localization. These data suggest that the brain uses multiple strategies to integrate multisensory information.     

视听刺激突显性对视觉主导效应的影响

本研究使用空间任务-转换范式,控制视、听刺激的突显性,探讨自下而上注意对视觉主导效应的影响。结果表明视、听刺激突显性显著地影响视觉主导效应,实验一中当听觉刺激为高突显性时,视觉主导效应显著减弱。实验二中当听觉刺激为高突显性并且视觉刺激为低突显性时,视觉主导效应进一步减弱但依然存在。结果支持偏向竞争理论,在跨通道视听交互过程中视觉刺激更具突显性,在多感觉整合过程中更具加工优势。     

The owl and the pussycat: Gaze cues and visuospatial orienting

Recent research has shown that nonpredictive gaze cues trigger reflexive shifts in attention toward the looked-at location. But just how generalizable is this spatial cuing effect? In particular, are people especially tuned to gaze cues provided by conspecifics, or can comparable shifts in visual attention be triggered by other cue providers and directional cues? To investigate these issues, we used a standard cuing paradigm to compare the attentional orienting produced by different cue providers (i.e., animate vs. inanimate) and directional cues (i.e., eyes vs. arrows). The results of three experiments revealed that attentional orienting was insensitive to both the identity of the cue provider and the nature of the triggering cue. However, compared with arrows, gaze cues prompted a general enhancement in the efficiency of processing operations. We consider the implications of these findings for accounts of reflexive visual orienting.