Spatial distortion induced by imperceptible visual stimuli

Previous studies have explored the effects of attention on spatial representation. Specifically, in the attentional repulsion effect, a transient visual cue that captures attention has been shown to alter the perceived position of a target stimulus to the direction away from the cue. The effect is also susceptible to retrospective influence, that attention appears to attract the target when the cue appears afterwards. This study examined the necessity of visual awareness of the cue in these phenomena. We found that when the cues were rendered invisible by backward visual masks, both repulsion and attraction effects were weakened but still observed. The results suggest that the effects possibly depend on processes that are not necessarily associated with conscious visual awareness of the cues. We conjecture that attentional shift produced by the weak, invisible cues may play a role in spatial distortion; but other possible accounts including non-attentional ones are also discussed.     

Cue set size effects: Sampling activated associates or cross-target interference?

Previous findings indicate that test cues linked to more associates (more knowledge) produce lower levels of recall than cues with fewer associates. One hypothesis attributes this effect to cross-target interference arising during retrieval on the assumption that cues with more associates are more likely to be indirectly connected to studied words other than the target. Another attributes the effect to sampling associates of the cue on the assumption that the probability of sampling the target declines as more associates are activated. Findings from four experiments showed that recall varied with cue set size, and, more importantly, that cue set size affected recall independently of the interference produced by cross-target connections. These results were interpreted as supporting a model that attributes cue set size effects to sampling processes associated with the intersection of the test cue and its associates with the target and its associates.     

Tracking the time course of phonetic cue integration during spoken word recognition

Speech perception requires listeners to integrate multiple cues that each contribute to judgments about a phonetic category. Classic studies of trading relations assessed the weights attached to each cue but did not explore the time course of cue integration. Here, we provide the first direct evidence that asynchronous cues to voicing (/b/ vs. /p/) and manner (/b/ vs. /w/) contrasts become available to the listener at different times during spoken word recognition. Using the visual world paradigm, we show that the probability of eye movements to pictures of target and of competitor objects diverge at different points in time after the onset of the target word. These points of divergence correspond to the availability of early (voice onset time or formant transition slope) and late (vowel length) cues to voicing and manner contrasts. These results support a model of cue integration in which phonetic cues are used for lexical access as soon as they are available.     

Does attention alter appearance?

Abrupt onsets in the visual field can change the appearance of subsequent stimuli, according to one interpretation, by engaging an attentional mechanism that increases effective stimulus contrast. However, abrupt onsets can also engage capacity-unlimited and thus attention-independent sensory mechanisms. We conducted a series of experiments to differentiate the sensory and attentional accounts. Observers compared the contrasts of uncued low-contrast peripheral targets with simultaneous targets cued by one of three cue types with different sensory attributes: white or black peripheral abrupt onsets and central gaze direction cues devoid of sensory activity near the target locations. Each cue facilitated the perception of perithreshold targets; however, the white abrupt onsets increased the perceived contrast of suprathreshold targets, whereas the black abrupt onsets tended to reduce the perceived contrast, and the gaze direction cues had no significant effect. The effectiveness of the gaze direction cues in automatically orienting attention was demonstrated in a control experiment in which they consistently speeded response times. The results suggest that sensory interaction, and not attention, is responsible for changes in appearance.     

Cue familiarity but not target retrievability enhances feeling-of-knowing judgments.

Two hypotheses concerning people's ability to predict later memory performance for unrecalled items were investigated. The target retrievability hypothesis states that feeling-of-knowing judgments (FKJs) are based on partial target information; and the cue familiarity hypothesis asserts that they are based on recognition of the cues. In Experiments 1 and 2, subjects either generated or read the targets of paired associates. Half of the cues had been primed in a pleasantness-rating task. The generation manipulation increased recall but had no effect on FKJs. Cue priming had no effect on recall but increased FKJs. In Experiment 3, using general information questions, primed after the initial recall attempt, both cue and target priming increased FKJs. Experiment 4, which remedied difficulties in Experiment 3, showed no effect of target priming whereas cue priming increased FKJs. The results favor the cue familiarity hypothesis.     

The interplay between nonsymbolic number and its continuous visual properties

To date, researchers investigating nonsymbolic number processes devoted little attention to the visual properties of their stimuli. This is unexpected, as nonsymbolic number is defined by its visual characteristics. When number changes, its visual properties change accordingly. In this study, we investigated the influence of different visual properties on nonsymbolic number processes and show that the current assumptions about the relation between number and its visual characteristics are incorrect. Similar to previous studies, we controlled the visual cues: Each visual cue was not predictive of number. Nevertheless, participants showed congruency effects induced by the visual properties of the stimuli. These congruency effects scaled with the number of visual cues manipulated, implicating that people do not extract number from a visual scene independent of its visual cues. Instead, number judgments are based on the integration of information from multiple visual cues. Consequently, current ways to control the visual cues of the number stimuli are insufficient, as they control only a single variable at the time. And, more important, the existence of an approximate number system that can extract number independent of the visual cues appears unlikely. We therefore propose that number judgment is the result of the weighing of several distinct visual cues. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

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。     

不同搜索情境下老化对自上而下注意加工的影响

在视觉搜索过程中,老年人是否可以在不同情境下调节自上而下和自下而上的加工水平尚不明确。为了探讨老化对认知灵活性的影响,研究采用空间线索范式,通过比较有效线索和无效线索来考察对线索的注意加工水平（注意捕获、注意抑制）,通过比较目标相关和目标无关线索的注意加工水平来考察自上而下和自下而上的作用,通过改变分心物一致性来调控不同的目标凸显情境。结果发现,年轻组在目标非凸显时的空间线索效应高于目标凸显时,表明年轻人会依据目标凸显性调整自上而下的加工水平;但老年组却没有产生这种差异,其更依赖自上而下的加工,注意系统会对目标相关的线索进行注意捕获,对目标无关的线索进行注意抑制。结果表明,随着年龄的增长,认知控制的灵活性下降,表现出对自上而下加工较多的依赖;此外,老年人依然保留着注意捕获和注意抑制的能力,这对认知老化中抑制能力受损的观点提出了挑战。     

The effects of environmental changes on one-handed catching

Ball catching involves predicting the time and place of arrival of a mobile object. Visual cues of various kinds may help a ball catcher to perform this task successfully. The aims of the present study were (a) to assess the role of the environment in the spatiotemporal planning of ball-catching movements and (b) to determine what specific cues are actually used for this purpose. In the first experiment described here, subjects' catching performances were compared under four different environmental conditions, namely, normal lighting, ultraviolet light with no background, ultraviolet light with a densely structured background, and ultraviolet light with a sparsely structured background. Our results showed that the sight of the mobile object alone does not provide enough information for a subject to achieve his maximum performance level. Accurately assessing the point of arrival of the ball requires the use of relative visual cues. The environment is also a source of visual cues used to assess the time of arrival of the ball. A second experiment was carried out with a view to determining the exact nature of the visual cues used. Here, the orientation (frontal vs. oblique plane) and the apparent visual angle (6 degrees vs. 42 degrees ) of the background were made to vary. The results of this experiment showed that the orientation of the background affected the percentage of spatial errors produced by the subjects, whereas the apparent visual angle affected the percentage of temporal errors. The relative velocity cue generated by the masking of successive structures in the environment by the oncoming ball seems to have been taking into account in estimating the time of arrival of the ball. This cue seems to be of crucial importance during the 200 ms prior to the time of contact between the ball and the subject's hand. This finding supports the idea that the method used to assess the time to contact may involve velocity information.     

Retrospective perceptual distortion of position representation does not lead to delayed localization

Previous studies have reported retrospective influences of visual events that occur after target events. In the attentional attraction effect, a position cue presented after a target stimulus distorts the target’s position towards that of the cue. The present study explored the temporal relationship between stimulus presentation and reaction time (RT) in this effect in two experiments. Participants performed a speeded localization task on two vertical lines, the positions of which were to be distorted by an additional attentional cue. No significant difference in RTs was found between the conditions with simultaneous and delayed cues. RTRT was modulated by the perceived (rather than physical) alignment of the lines. In Experiment 2, we manipulated the strength of attentional capture by modulating the color relevance of the cue to the target. Trials with cues producing stronger attentional capture (with cues of a different color from the targets) were found to induce apparently stronger distortion effects. This result favors the notion that the observed repulsion and attraction effects are driven by attentional mechanisms. Overall, the results imply that the attentional shift induced by the cue might occur rapidly and complete before the establishment of conscious location representation of the cue and the target without affecting overall response time.     

Does crossmodal correspondence modulate the facilitatory effect of auditory cues on visual search?

The ??pip-and-pop effect?? refers to the facilitation of search for a visual target (a horizontal or vertical bar whose color changes frequently) among multiple visual distractors (tilted bars also changing color unpredictably) by the presentation of a spatially uninformative auditory cue synchronized with the color change of the visual target. In the present study, the visual stimuli in the search display changed brightness instead of color, and the crossmodal congruency between the pitch of the auditory cue and the brightness of the visual target was manipulated. When cue presence and cue congruency were randomly varied between trials (Experiment 1), both congruent cues (low-frequency tones synchronized with dark target states or high-frequency tones synchronized with bright target states) and incongruent cues (the reversed mapping) facilitated visual search performance equally, relative to a no-cue baseline condition. However, when cue congruency was blocked and the participants were informed about the pitch?Cbrightness mapping in the cue-present blocks (Experiment 2), performance was significantly enhanced when the cue and target were crossmodally congruent as compared to when they were incongruent. These results therefore suggest that the crossmodal congruency between auditory pitch and visual brightness can influence performance in the pip-and-pop task by means of top-down facilitation.     

Automaticity and the capture of attention by a peripheral display change

The proposal that peripheral visual changes (cues) tend to summon attention automatically was tested by studying the effect of peripheral cueing on simple detection latency. Delay between cue onset and target onset, the contingent relationship between cue location and target location, and instructions to subjects were manipulated. Results showed that a peripheral display change could capture attention even when the target was far more likely to appear at an uncued location. When subjects were explicitly informed that targets were likely to appear away from the cued location they were able to suppress this effect, but were unable completely to reverse it by rapidly orienting attention towards the uncued side. Hence the process appears to be automatic in the sense that it occurs unless there are explicit instructions to the contrary. With explicit instructions the processing operation can be suppressed, but not completely reversed. This work was supported by the U.K. Admiralty Research Establishment (Research Agreement No. 53482).     

Attentional localization prior to simple and directed manual responses

The relationship between attention and the programming of motor responses was investigated, using a paradigm in which the onsets of targets for movements were preceded by peripheral attentional cues. Simple (button release) and reaching manual responses were compared under conditions in which the subjects either made saccades toward the target location or refrained from making eye movements. The timing of the movement onset was used as the dependent measure for both simple and reaching manual responses. Eye movement latencies were also measured. A follow-up experiment measured the effect of the same peripheral cuing procedure on purely visual processes, using signal detection measures of visual sensitivity and response bias. The results of the first experiment showed that reaction time (RT) increased with the distance between the cued and the target locations. Stronger distance effects were observed when goal-directed responses were required, which suggests enhanced attentional localization of target positions under these conditions. The requirement to generate an eye movement response was found to delay simple manual RTs. However, mean reaching RTs were unaffected by the eye movement condition. Distance gradients on eye movement latencies were relatively shallow, as compared with those on goal-directed manual responses. The second experiment showed that the peripheral cue had only a very small effect on visual detection sensitivity in the absence of directed motor responses. It is concluded that cue-target distance effects with peripheral cues are modulated by the motor-programming requirements of the task. The effect of the peripheral cue on eye movement latencies was qualitatively different from that observed on manual RTs, indicating the existence of separate neural representations underlying both response types. At the same time, the interactions between response modalities are consistent with a supramodal representation of attentional space, within which different motor programs may interact.     

Attentional localization prior to simpleand directed manual responses

The relationship between attention and the programming of motor responses was investigated, using a paradigm in which the onsets of targets for movements were preceded by peripheral attentional cues. Simple (button release) and reaching manual responses were compared under conditions in which the subjects either made saccades toward the target location or refrained from making eye movements. The timing of the movement onset was used as the dependent measure for both simple and reaching manual responses. Eye movement latencies were also measured. A follow-up experiment measured the effect of the same peripheral cuing procedure on purely visual processes, using signal detection mea-sures of visual sensitivity and response bias. The results of the first experiment showed that reaction time (RT) increased with the distance between the cued and the target locations. Stronger distance ef-fects were observed when goal-directed responses were required, which suggests enhanced attentional localization of target positions under these conditions. The requirement to generate an eye movement response was found to delay simple manual RTs. However, mean reaching RTs were unaffected by the eye movement condition. Distance gradients on eye movement latencies were relatively shallow, as compared with those on goal-directed manual responses. The second experiment showed that the peripheral cue had only a very small effect on visual detection sensitivity in the absence of directed motor responses. It is concluded that cue-target distance effects with peripheral cues are modulated by the motor-programming requirements of the task. The effect of the peripheral cue on eye movement latencies was qualitatively different from that observed on manual RTs, indicating the existence of separate neural representations underlying both response types. At the same time, the interactions be-tween response modalities are consistent with a supramodal representation of attentional space, within which different motor programs may interact.     

Effects of Unimodal and Multimodal Cues About Threat Locations on Target Acquisition and Workload

Two studies were conducted to examine the effects of unimodal and multimodal cueing techniques for indicating the location of threats on target acquisition, the recall of information from concurrent communications, and perceived workload. One visual, two auditory (i.e., nonspatial speech and spatial tones [3-D]), and one tactile cue were assessed in Experiment 1. Experiment 2 examined the effects of combinations of the cues assessed in the first investigation: visual + nonspatial speech, visual + spatial tones, visual + tactile, and nonspatial speech + tactile. A unimodal, “visual only” condition was included as a baseline to determine the extent to which a supplementary cue might influence changes in performance and workload. The results of the studies indicated that time to first shot and the percentage of hits can be improved and workload reduced by providing cues about target location. The multimodal cues did not yield significant improvements in performance or workload beyond that achieved by the unimodal visual cue.     

Using eye-tracking to study audio-visual perceptual integration

Perceptual integration of audio-visual stimuli is fundamental to our everyday conscious experience. Eye-movement analysis may be a suitable tool for studying such integration, since eye movements respond to auditory as well as visual input. Previous studies have shown that additional auditory cues in visual-search tasks can guide eye movements more efficiently and reduce their latency. However, these auditory cues were task-relevant since they indicated the target position and onset time. Therefore, the observed effects may have been due to subjects using the cues as additional information to maximize their performance, without perceptually integrating them with the visual displays. Here, we combine a visual-tracking task with a continuous, task-irrelevant sound from a stationary source to demonstrate that audio-visual perceptual integration affects low-level oculomotor mechanisms. Auditory stimuli of constant, increasing, or decreasing pitch were presented. All sound categories induced more smooth-pursuit eye movement than silence, with the greatest effect occurring with stimuli of increasing pitch. A possible explanation is that integration of the visual scene with continuous sound creates the perception of continuous visual motion. Increasing pitch may amplify this effect through its common association with accelerating motion.     

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.     

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.     

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.     

早期ERP效应与视觉注意空间等级的脑调节机制

通过事件相关电位(ERP)记录研究注意的空间等级的脑内时程动态变化。视觉搜索任务的目标受不同大小提示范围的启动。提示范围增大时,识别目标的反应时延长,P1波幅增大而N1波幅减小,该效应在短间隔条件下尤为明显。P1增大反映了促进目标识别时,适当注意范围的空间等级变化需要额外的运算资源。而N1波幅减小则可能扩散了空间注意倾斜。研究结果提供了以下电生理学证据：注意空间等级的改变调节了早期视皮层的神经活动,并激活了视觉搜索中至少2个时间重叠的ERP成分。