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.     

计算机虚拟技术训练辅助盲人构建空间表征之研究

摘要 由于视觉经验的缺乏,盲人的空间认知存在一定的缺陷,尤其表现在对现实环境的空间布局认识存在困难。本研究欲探究计算机虚拟技术手段辅助盲人建构表征的成效,并在此基础上探究盲人定向行走的效果。本研究是一个现场实验,采用随机分配的方式将全盲被试分为三组,之后让被试接受三种不同的实验处理,即计算机虚拟技术、触觉地图和人导处理,最后接受空间任务测试,测试不仅考察被试对环境空间布局的认识,而且还测量了被试在现实环境的行走探路效率。结果发现,虚拟技术组的被试不仅能够对整个实验环境形成清晰整体的认识,而且还能借助形成的空间表征在测验场地有效地实施定向行走。从研究结果得知,计算机虚拟技术这一手段对应用于改善盲人空间表征系统及提高盲人定向行走训练效率具有一定的积极意义。     

Blindness enhances tactile acuity and haptic 3-D shape discrimination

This study compared the sensory and perceptual abilities of the blind and sighted. The 32 participants were required to perform two tasks: tactile grating orientation discrimination (to determine tactile acuity) and haptic three-dimensional (3-D) shape discrimination. The results indicated that the blind outperformed their sighted counterparts (individually matched for both age and sex) on both tactile tasks. The improvements in tactile acuity that accompanied blindness occurred for all blind groups (congenital, early, and late). However, the improvements in haptic 3-D shape discrimination only occurred for the early-onset and late-onset blindness groups; the performance of the congenitally blind was no better than that of the sighted controls. The results of the present study demonstrate that blindness does lead to an enhancement of tactile abilities, but they also suggest that early visual experience may play a role in facilitating haptic 3-D shape discrimination.     

Vision of a pictorial hand modulates visual-tactile interactions

The participants in this study discriminated the position of tactile target stimuli presented at the tip or the base of the forefinger of one of the participants’ hands, while ignoring visual distractor stimuli. The visual distractor stimuli were presented from two circles on a display aligned with the tactile targets in Experiment 1 or orthogonal to them in Experiment 2. Tactile discrimination performance was slower and less accurate when the visual distractor stimuli were presented from incongruent locations relative to the tactile target stimuli (e.g., tactile target at the base of the finger with top visual distractor) highlighting a cross-modal congruency effect. We examined whether the presence and orientation of a simple line drawing of a hand, which was superimposed on the visual distractor stimuli, would modulate the cross-modal congruency effects. When the tactile targets and the visual distractors were spatially aligned, the modulatory effects of the hand picture were small (Experiment 1). However, when they were spatially misaligned, the effects were much larger, and the direction of the cross-modal congruency effects changed in accordance with the orientation of the picture of the hand, as if the hand picture corresponded to the participants’ own stimulated hand (Experiment 2). The results suggest that the two-dimensional picture of a hand can modulate processes maintaining our internal body representation. We also observed that the cross-modal congruency effects were influenced by the postures of the stimulated and the responding hands. These results reveal the complex nature of spatial interactions among vision, touch, and proprioception.     

Incidental and intentional visual memory: What memories are and are not affected by encoding tasks?

Prior research into the impact of encoding tasks on visual memory (Castelhano & Henderson, 2005) indicated that incidental and intentional encoding tasks led to similar memory performance. The current study investigated whether different encoding tasks impacted visual memories equally for all types of objects in a conjunction search (e.g., targets, colour distractors, object category distractors, or distractors unrelated to the target). In sequences of pictures, participants searched for prespecified targets (e.g., green apple; Experiment 1), memorized all objects (Experiment 2), searched for specified targets while memorizing all objects (Experiment 3), searched for postidentified targets (Experiment 4), or memorized all objects with one object prespecified (Experiment 5). Encoding task significantly improved visual memory for targets and led to worse memory for unrelated distractors, but did not influence visual memory of distractors that were related to the target's colour or object category. The differential influence of encoding task indicates that the relative importance of the object both positively and negatively influences the memory retained.     

A behavioral study of distraction by vibrotactile novelty

Past research has demonstrated that the occurrence of unexpected task-irrelevant changes in the auditory or visual sensory channels captured attention in an obligatory fashion, hindering behavioral performance in ongoing auditory or visual categorization tasks and generating orientation and re-orientation electrophysiological responses. We report the first experiment extending the behavioral study of cross-modal distraction to tactile novelty. Using a vibrotactile-visual cross-modal oddball task and a bespoke hand-arm vibration device, we found that participants were significantly slower at categorizing the parity of visually presented digits following a rare and unexpected change in vibrotactile stimulation (novelty distraction), and that this effect extended to the subsequent trial (postnovelty distraction). These results are in line with past research on auditory and visual novelty and fit the proposition of common and amodal cognitive mechanisms for the involuntary detection of change.     

An age-related view of the role of object and spatial cognitive styles in distance estimation

Distance estimations require identifying characteristics of the object and its spatial surroundings. With the present study, we examined the relationship between visual object and spatial (cognitive) styles and distance estimations in children and adults. Participants were administered the Object-Spatial Imagery Questionnaire (OSIQ) and two distance estimation tasks—one required estimating reach distance (reach task [RT]) from the self and the other required estimating distance between targets (perceptual task[PT]). Overall, our findings indicated that age was the best predictor of estimation for RT and PT tasks, and individuals were more accurate in the task requiring an egocentric frame of reference (RT) compared to tasks that require allocentric judgements (PT). In addition, children had higher ratings on cognitive styles in comparison to adults, but both object and spatial styles only related to RT accuracy in adults. Cognitive styles seem to be associated to distance estimation accuracy, but only when there is a clear preference.     

The development of organized visual search

Visual search plays an important role in guiding behavior. Children have more difficulty performing conjunction search tasks than adults. The present research evaluates whether developmental differences in children's ability to organize serial visual search (i.e., search organization skills) contribute to performance limitations in a typical conjunction search task. We evaluated 134 children between the ages of 2 and 17 on separate tasks measuring search for targets defined by a conjunction of features or by distinct features. Our results demonstrated that children organize their visual search better as they get older. As children's skills at organizing visual search improve they become more accurate at locating targets with conjunction of features amongst distractors, but not for targets with distinct features. Developmental limitations in children's abilities to organize their visual search of the environment are an important component of poor conjunction search in young children. In addition, our findings provide preliminary evidence that, like other visuospatial tasks, exposure to reading may influence children's spatial orientation to the visual environment when performing a visual search.     

The Stationary-Gaze Task Should Not Be Systematically Used as the Control Task in Studies of Postural Control

In studies of postural control, a control task is often used to understand significant effects obtained with experimental manipulations. This task should be the easiest task and (therefore) engage the lowest behavioral variability and cognitive workload. Since 1983, the stationary-gaze task is considered as the most relevant control task. Instead, the authors expected that free looking at small targets (white paper or images; visual angle: 12°) could be an easier task. To verify this assumption, 16 young individuals performed stationary-gaze, white-panel, and free-viewing 12° tasks in steady and relaxed stances. The stationary-gaze task led to significantly higher cognitive workload (mean score in the National Aeronotics and Space Administration Task Load Index questionnaire), higher interindividual body (head, neck, and lower back) linear variability, and higher interindividual body angular variability—not systematically yet—than both other tasks. There was more cognitive workload in steady than relaxed stances. The authors also tested if a free-viewing 24° task could lead to greater angular displacement, and hence greater body sway, than could the other tasks in relaxed stance. Unexpectedly, the participants mostly moved their eyes and not their body in this task. In the discussion, the authors explain why the stationary-gaze task may not be an ideal control task and how to choose this neutral task.     

Responses to visual,tactile and visual–tactile forward collision warnings while gaze on and off the road

The objective of the current driving simulator study (N = 20) was to assess brake reaction time (BRT) and subjective experiences of visual (V), tactile (T), and visual–tactile (VT) collision warnings when the drivers’ visual orientation was manipulated between four locations (i.e., road and three different mirror locations). V warning was a blinking light in a windscreen, T warning was implemented by a vibrating accelerator pedal, and VT warning was their synchronous combination. The results showed that all the warning stimuli were detected in 100% accuracy in all visual orientations, but T and VT warnings produced significantly faster BRTs when compared to V warning. It was found that BRT to V warning was the slowest while observing the furthermost side mirror. However, BRTs following T and VT warnings remained unaffected by the visual orientations. Both the objective BRT measurements and subjective evaluations indicated a superiority of T and VT warnings against a sole V warning, not only in general terms, but also separately for different visual orientations.     

Visual tracking in young infants: Evidence for object identity or object permanence?

Previous research has shown that 5-month-old infants visually anticipate a moving object's appearance after it disappears behind a screen. This experiment assesses the underlying basis for such anticipatory tracking. Three tracking tasks were presented to 5- and 9-month-old infants. In the Permanence task, the object's continuous existence was apparently violated while it was behind a screen. In the Feature and Trajectory tasks, the object's features or trajectory changed while behind the screen. Disruptions in the infant's smooth visual pursuit of the object were recorded. Five-mont-olds showed disruptions of visual tracking in the Feature and Trajectory tasks, but not in the Permanence task. The tracking of the 9-month-olds was disrupted in all three tasks. We conclude that both 5- and 9-month-olds possess rules specifying the identity of a moving object which is occluded. For 5-month-olds these rules are based upon the object's features and trajectory, but not upon a concept of object permanence. For 9-month-olds all three rules—feature, trajectory, and permanence—are utilized in visual tracking.     

Cross-modal attention modulates tactile subitizing but not tactile numerosity estimation

Debate remains about whether the same attentional mechanism subserves subitizing (with number of items less than or equal to 4) and numerosity estimation (with number of items equal to or larger than 5), and evidence is scarce from the tactile modality. Here, we examined tactile numerosity perception. Using tactile Braille displays, participants completed the following three main tasks: (1) Unisensory task with focused attention: Participants reported the number (1~12) of the tactile pins. (2) Unisensory task with divided attention: Participants compared the numbers of pins across the upper and lower area of their left index fingers, in addition to reporting the number of tactile pins on their right index fingers. (3) Cross-modal task with divided attention: Participants reported the number of tactile pins and compared the numbers of visual dots across the upper and lower part of a (illusory) rectangle that overlaid the tactile stimuli. We found that performance of subitizing rather than estimation was interfered with in dual tasks, regardless of whether distractor events were from the same modality (tactile modality) or from a different modality (visual modality). Moreover, a further test of visual/tactile working memory capacity revealed that the precision of tactile subitizing, in the presence of a visual distractor, was correlated with the capacity of visual working memory, not of tactile working memory. Overall, our study revealed that tactile numerosity perception is accounted for by amodal attentional modulation yet by differential attentional mechanisms in terms of subitizing and estimation.     

Lateralization of temporal lobe dysfunction and verbal encoding

The contribution of encoding deficits to verbal-learning difficulties known to be associated with temporal lobe dysfunction was investigated. Auditory and visual false-recognition tasks, which assess verbal encoding strategies, were given to patients with left-temporal-lobe (LTL) and right-temporal-lobe (RTL) surgical excisions and to a group of normal controls (NC). On both auditory and visual tasks, LTL patients made significantly more false-recognition errors than the other subjects on related, but not unrelated, words in the test list. The findings indicate that LTL patients are able to initially encode verbal material and that a breakdown in information processing occurs at a later stage. On the auditory tasks, the performance of RTL patients did not differ from that of NC subjects. However, on the visual tasks, RTL patients, as compared to both LTL and NC subjects, made fewer false-recognition errors. The performance of RTL patients, in contrast to LTL patients, could be interpreted as a reduced encoding of the visual attribute of verbal material. Another possible explanation considered was difficulty in familiarity discrimination.     

From body shadows to bodily attention: Automatic orienting of tactile attention driven by cast shadows

Body shadows orient attention to the body-part casting the shadow. We have investigated the automaticity of this phenomenon, by addressing its time-course and its resistance to contextual manipulations. When targets were tactile stimuli at the hands (Exp.1) or visual stimuli near the body-shadow (Exp.2), cueing effects emerged regardless of the delay between shadow and target onset (100, 600, 1200, 2400 ms). This suggests a fast and sustained attention orienting to body-shadows, that involves both the space occupied by shadows (extra-personal space) and the space the shadow refers to (own body). When target type became unpredictable (tactile or visual), shadow-cueing effects remained robust only for tactile targets, as visual stimuli showed no overall reliable effects, regardless of whether they occurred near the shadow (Exp.3) or near the body (Exp.4). We conclude that mandatory attention shifts triggered by body-shadows are limited to tactile targets and, instead, are less automatic for visual stimuli.     

Perceptual skills of children with developmental coordination disorder

The aim of this study was to investigate whether children with a Developmental Coordination Disorder (DCD) experience problems in the processing of visual, proprioceptive or tactile information. Different aspects of visual perception were tested with the Developmental Test of Visual Perception (DTVP-2), tactile perception was assessed with the Tactual Performance Test (TPT), and a manual pointing task was employed to measure the ability to use visual and proprioceptive information in goal-directed movements. Nineteen children with DCD and nineteen age and sex-matched controls participated in this study. Differences between groups were most pronounced in the subtests measuring visual-motor integration of the DTVP-2, and in two subtests measuring visual perception (visual closure and position in space). On average the children with DCD performed slightly below the norm for tactile perception, with only three children failing the norm. On the manual pointing task, children with DCD made inconsistent responses towards the targets in all three conditions (visual, visual-proprioceptive and proprioceptive condition). No significant differences between groups were found for absolute error. Inspection of the individual data revealed that only two children failed on the majority of perceptual tasks in the three modalities. Across tasks, no consistent pattern of deficits appeared, illustrating the heterogeneity of the problems of children with DCD.     

Perceptual learning in visual conjunction search.

Perceptual learning in colour/orientation visual conjunction search was examined in five experiments. Good transfer occurred to other conjunction arrays when only one element of the conjunction (either colour or orientation) was changed. When both elements (colour and orientation) were changed, but the same feature spaces were used (i.e. other colours and orientations) or when a new dimension was introduced to the transfer task (shapes instead of orientation), transfer was poor. The results suggest that perceptual learning of visual conjunction search is constrained mainly by stimulus parameters rather than by changes in cognitive strategies which are common to all search tasks. Contrary to other reports we found little evidence of long-term retention of learning.     

Visual search for dimensionally redundant pop-out targets: Redundancy gains in compound tasks

Two visual search experiments investigated the detection of odd-one-out feature targets redundantly defined on multiple dimensions. Targets differed from the distractors in either orientation or colour or both (redundant targets). In Experiment 1, the three types of target were presented either in separate trial blocks or randomized within blocks, and the task involved either a simple target detection response or a “compound” response based on the position of dials inside the target. Mean reaction times (RTs) were faster to redundant targets than to singly defined targets, with greater gains in simple detection than in compound tasks. Further, simple detection RTs to redundant targets were faster than the fastest RTs to singly defined targets, violating Miller's (1982) “race model inequality” (RMI). Experiment 2 showed that, with compound tasks, mean RT redundancy gains (and violations of the RMI) depend on practice. The results suggest that separate colour and orientation feature contrast signals coactivate perceptual mechanisms involved in target detection.     

Interactions Between Exogenous Auditory and Visual Spatial Attention

Six experiments were carried out to investigate the issue of cross-modality between exogenous auditory and visual spatial attention employing Posner's cueing paradigm in detection, localization, and discrimination tasks. Results indicated cueing in detection tasks with visual or auditory cues and visual targets but not with auditory targets (Experiment 1). In the localization tasks, cueing was found with both visual and auditory targets. Inhibition of return was apparent only in the within-modality conditions (Experiment 2). This suggests that it is important whether the attention system is activated directly (within a modality) or indirectly (between modalities). Increasing the cue validity from 50% to 80% influenced performance only in the localization task (Experiment 4). These findings are interpreted as being indicative for modality-specific but interacting attention mechanisms. The results of Experiments 5 and 6 (up/down discrimination tasks) also show cross-modal cueing but not with visual cues and auditory targets. Furthermore, there was no inhibition of return in any condition. This suggests that some cueing effects might be task dependent.     

Effect of structuring the workspace on cognitive and sensorimotor distance estimation: no dissociation between perception and action

Independent processing of visual information for perception and action is supported by studies about visual illusions, which showed that context information influences overtjudgment but not reaching attempts. The objection was raised, however, that these two types of performance are notdirectly comparable, since they generally focus on different properties of the visual input. The goal of the present study was to quantify the influence of context information (in the form of a textured background) on the cognitive and sensorimotor processing of egocentric distance. We found that the subjective area comprising reachable objects (probed with a cognitive task) decreased, whereas the amplitude of reaching movement (probed with a sensorimotor task) increased in the presence of the textured background with both binocular and monocular viewing. Directional motor performance was not affected by the experimental conditions, but there was a tendency for the kinematic parameters to mimic trajectory variations. The similar but opposite effects of the textured background in the cognitive and sensorimotor tasks suggested that in both tasks the visual targets were perceived as closer when they were presented in a sparse environment. A common explanation for the opposite effects was confirmed by the percentage of background influence, which was highly correlated in the two tasks. We conclude that visual processing for perception and action cannot be dissociated from context influence, since it does not differ when the tasks entail the processing of similar spatial characteristics.     

How am I doing? Performance feedback mitigates the effects of mental fatigue on endurance exercise performance

Mental fatigue induced by an earlier cognitive task can impair performance on a subsequent physical task. The current study investigated whether such performance impairment could be mitigated by performance feedback. In an experimental sequential-task design, 63 sport science students completed a series of three tasks: 5-min physical (pre-test), 20-min cognitive, 5-min physical (post-test). Participants were randomly allocated to one of three groups: feedback (n = 23), no feedback (n = 20), control (n = 20). The physical tasks, which assessed force production during a self-paced rhythmic handgrip task as a measure of physical endurance performance, were performed with (feedback group) or without (no feedback group, control group) visual performance feedback. The cognitive tasks involved either completing a 2-back memory task to induce mental fatigue (feedback and no feedback groups) or watching a didactic film (control group). Self-report measures (fatigue, exertion, vigor, motivation) were collected throughout. The 2-back cognitive task increased mental fatigue, mental exertion and general fatigue in the feedback and no feedback groups compared to the control group. Relative to the pre-test physical task, post-test endurance performance declined in the no feedback group (−14.4%) but did not change in the control (−2.6%) and feedback (−2.4%) groups. This mitigation of performance effect was not accompanied by parallel changes in fatigue, exertion, vigor, or motivation. In conclusion, visual performance feedback mitigates the negative effects of mental fatigue on physical endurance performance.