How Are Different Properties of a Scene Encoded in Visual Memory?

Recent studies in scene perception suggest that much of what observers believe they see is not retained in visual memory. Depending on the roles they play in organizing the perception of a scene, different visual properties may require different amounts of attention to be incorporated into a mental representation of the scene. The goal of this study was to compare how three visual properties of scenes, colour, object position, and object presence, are encoded in visual memory. We used a variation on the change detection “flicker” task and measured the time to detect scene changes when: (1) a cue was provided regarding the type of change; and, (2) no cue was provided. We hypothesized that cueing would enhance the processing of visual properties that require more attention to be encoded into scene representations, whereas cueing would not have an effect for properties that are readily or automatically encoded in visual memory. In Experiment 1, we found that there was a cueing advantage for colour changes, but not for position or presence changes. In Experiment 2, we found the same cueing effect regardless of whether the colour change altered the configuration of the scene or not. These results are consistent with the idea that properties that typically help determine the configuration of the scene, for example, position and presence, are better encoded in scene representations than are surface properties such as colour.     

Signals for threat modulate attentional capture and holding: Fear-conditioning and extinction during the exogenous cueing task

This experiment investigated whether acquired signals for threat capture and hold visual attention. Cues that were presented in an exogenous attentional cueing task were emotionally modulated using a fear-conditioning paradigm. During acquisition, undergraduate students (55 women, 11 men) learned that one cue (CS+) of the attentional task was a signal for an aversive white noise burst (UCS, 100 dBA) and that another cue (CS?) signalled its nonoccurrence. In a subsequent extinction phase, no UCSs were presented anymore during the cueing task. Results indicated that during acquisition, the CS+ cues strongly captured and held visual attention in comparison with the CS? cues, and that these effects diminished during extinction.     

Differentiating visual and kinesthetic imagery in mental practice.

Through two experiments, the study sought to emphasize the usefulness of the visual and kinesthetic imagery in mental practice. In Experiment 1, it was hypothesized that when the task to be learned through mental practice necessitates the reproduction of a form by drawing, the visual image, which provides a wide span of apprehension, is more suitable than the kinesthetic image. On the other hand, the kinesthetic image that supplies inputs from the muscles' positions and movements should be more appropriate for the acquisition of the duration of the drawing. In Experiment 2, it was hypothesized that the task, transformed into a motor task necessitating minute coordination of the two hands, would benefit more from kinesthetic imagery. To have optimal control over what was actually experienced during mental practice, the participants' imagery skills were measured. The participants also benefited from prior imagery training. The results demonstrate that when using mental practice to initially acquire a task, visual imagery is better for tasks that emphasize form while kinesthetic imagery is better for those tasks that emphasize timing or minute coordination of the two hands.     

Abilities and strategies of blind and sighted subjects in visuo-spatial imagery

An active visuo-spatial memory task was used in order to determine the characteristics of mental imagery in subjects with and without visual experience. Subjects were instructed to generate a mental representation of verbally presented 2D patterns that were placed in a grid and to indicate how many pattern elements were in corresponding positions in the two halves of the grid according to a specific grid axis (vertical or horizontal). Unexpectedly, results showed a similar performance in early blind, late blind and sighted subjects. However, subjects' debriefing showed that the three groups used different strategies. The sighted and the late blind subjects took advantage of a visuo-spatial strategy. They generated a mental image of the matrix and they simplified this image to maintain only the relevant information in memory. In contrast, the early blind subjects encoded each pattern element by its location in a (X,Y) coordinate system without visual representation. This indicates that both early and late blind subjects are able to perform an active visuo-spatial imagery task as well as sighted subjects although they use different strategies.     

Partial pictures as imagery-retrieval cues in young children's prose recall.

Two experiments, involving first-grade children, were conducted to test a retrieval-inefficiency explanation for the failure of visual imagery to facilitate young children's prose recall. Consistent with this explanation, children who were given stimuli presumed to elicit visual imagery (“partial pictures”) both during the presentation of a story and at the time questions were asked about the story recalled more story content than children given the partial pictures only during story presentation. An alternative account of these findings—namely that they may be attributed to a general cueing effect—was ruled out in the second experiment. Cognitive-developmental aspects of visual imagery strategies in prosememory situations are discussed.     

Differential time course of implicit and explicit cueing by colour and orientation in visual search

Using a cued conjunction search task, Anderson, Heinke, and Humphreys (2010) demonstrated larger effects from cueing target colour than from cueing target orientation. In this study, we separated the implicit (nonexpectation-dependent) and explicit (expectation-dependent) effects of orientation and colour visual cues. In Experiment 1, we replicated the original findings for short cue durations (100–200 ms), demonstrating that cues matching the physical property of the target on 80% of trials exert a rapid effect on search. These early cueing effects on reaction times were supported by evidence of guidance from cues on early eye movements. Experiment 2 introduced a feature to the cue that randomly matched the colour or orientation of the target. When cue orientation was predictive, there were strong implicit effects based on whether the colour of the cue and target matched. When cue colour was predictive, there were only weak effects from the cue's orientation. Implicit effects from cue colour remained when orientation-predictive cues were used and colour was unlikely to predict the target (Experiment 3). The data suggest that strong effects of colour cueing result from a combination of implicit and explicit processes, whereas effects from orientation cues are largely limited to the explicit guidance of visual search.     

What clocks tell us about the neural correlates of spatial imagery

We review a series of experimental studies aimed at answering some critical questions about the neural basis of spatial imagery. Our group used functional magnetic resonance imaging (fMRI) to explore the neural correlates of an online behaviourally controlled spatial imagery task without need for visual presentation—the mental clock task. Subjects are asked to imagine pairs of times that are presented acoustically and to judge at which of the two times the clock hands form the greater angle. The cortical activation elicited by this task was contrasted with that obtained during other visual, perceptual, verbal, and spatial imagery tasks in several block design studies. Moreover, our group performed an event‐related fMRI study on the clock task to investigate the representation of component cognitive processes in spatial imagery. The bulk of our findings demonstrates that cortical areas in the posterior parietal cortex (PPC), along the intraparietal sulcus, are robustly involved in spatial mental imagery and in other tasks requiring spatial transformations. PPC is bilaterally involved in different kinds of spatial judgement. Yet the degree to which right and left PPC are activated in different tasks is a function of task requirements. From event‐related fMRI data we obtained evidence that left and right PPC are activated asynchronously during the clock task and this could reflect their different functional role in subserving cognitive components of visuospatial imagery.     

从表征和认知过程上看表象与知觉、记忆的关系

表象、知觉和记忆是一个整合的认知系统。由于知觉和记忆提供了表象生成的材料,因而三者共享相似的表征,并激活广泛而相似的脑区。然而在认知加工过程上三者存在一定的差异。与知觉相比,表象的编码方式更抽象、更依赖过去经验的参与且处理细节能力更弱;与记忆相比,表象更容易受无关信息的干扰。未来对三者关系的研究应关注不同来源和不同类型的表象与知觉、记忆之间的关系,以及工作记忆在三者关系中所起的作用。     

Concurrent adaptation to opposite visual distortions: impairment and cue

The present study compared single and dual adaptation to visuomotor rotations in different cueing conditions. Participants adapted either to a constant rotation or to opposing rotations (dual adaptation) applied in an alternating order. In Experiment 1, visual and corresponding postural cues were provided to indicate different rotation directions. In Experiment 2, either a visual or a postural cue was available. In all cueing conditions, substantial dual adaptation was observed, although it was attenuated in comparison to single adaptation. Analysis of switching costs determined as the performance difference between the last trial before and the first trial after the change of rotation direction suggested substantial advantage of the visual cue compared to the postural cue, which was in line with previous findings demonstrating the dominance of visual sense in movement representation and control.     

What is the link between language and spatial images? Behavioral and neural findings in blind and sighted individuals

In order to find objects or places in the world, multiple sources of information, such as visual input, auditory input and asking for directions, can help you. These different sources of information can be converged into a spatial image, which represents configurational characteristics of the world. This paper discusses the findings on the nature of spatial images and the role of spatial language in generating these spatial images in both blind and sighted individuals. Congenitally blind individuals have never experienced visual input, yet they are able to perform several tasks traditionally associated with spatial imagery, such as mental scanning, mental pathway completions and mental clock time comparison, though perhaps not always in a similar manner as sighted. Therefore, they offer invaluable insights into the exact nature of spatial images. We will argue that spatial imagery exceeds the input from different input modalities to form an abstract mental representation while maintaining connections with the input modalities. This suggests that the nature of spatial images is supramodal, which can explain functional equivalent results from verbal and perceptual inputs for spatial situations and subtle to moderate behavioral differences between the blind and sighted.     

Oculomotor interference during manual response preparation: evidence from the response-cueing paradigm

Preparation provided by visual location cues is known to speed up behavior. However, the role of concurrent saccades in response to visual cues remains unclear. In this study, participants performed a spatial precueing task by pressing one of four response keys with one of four fingers (two of each hand) while eye movements were monitored. Prior to the stimulus, we presented a neutral cue (baseline), a hand cue (corresponding to left vs. right positions), or a finger cue (corresponding to inner vs. outer positions). Participants either remained fixated on a central fixation point or moved their eyes freely. The results demonstrated that saccades during the cueing interval altered the pattern of cueing effects. Finger cueing trials in which saccades were spatially incompatible (vs. compatible) with the subsequently required manual response exhibited slower manual RTs. We propose that interference between saccades and manual responses affects manual motor preparation.     

Cross-modal exogenous attention and distance effects in vision and hearing

In the present study we investigated cross-modal orienting in vision and hearing by using a cueing task with four different horizontal locations. Our main interest concerned cue–target distance effects, which might further our insight in the characteristics of cross-modal spatial attention mechanisms. A very consistent pattern was observed for both the unimodal (cue and target were both visual or auditory) and the cross-modal conditions (cue and target from different modalities). RTs to valid trials were faster than for invalid trials, and, most interestingly, there was a distance effect: RTs increased with greater cue–target distance. This applied to detection of visual targets and to localisation of both visual and auditory targets. The time interval between cue and target was also varied. Surprisingly, there was no indication of inhibition of return even with the longest cue–target intervals. In order to assess the role of endogenous (strategic) factors in exogenous spatial attention we increased in two additional experiments the cue validity from 25% to 80%. This appeared to have no large influence on the cueing pattern in both the detection and localisation tasks. Currently, it is assumed that spatial attention is organised in multiple strongly linked modality-specific systems. The foregoing results are discussed with respect to this supposed organisation.     

Individual differences in spatial mental imagery

In this article, we report a new image-scanning paradigm that allowed us to measure objectively individual differences in spatial mental imagery—specifically, imagery for location. Participants were asked to determine whether an arrow was pointing at a dot using a visual mental image of an array of dots. The degree of precision required to discriminate “yes” from “no” trials was varied. In Experiment 1, the time to scan increasing distances, as well as the number of errors, increased when greater precision was required to make a judgement. The results in Experiment 2 replicated those results while controlling for possible biases. When greater precision is required, the accuracy of the spatial image becomes increasingly important—and hence the effect of precision in the task reflects the accuracy of the image. In Experiment 3, this measure was shown to be related to scores on the Paper Folding test, on the Paper Form Board test, and on the visuospatial items on Raven's Advanced Progressive Matrices—but not to scores on questionnaires measuring object–based mental imagery. Thus, we provide evidence that classical standardized spatial tests rely on spatial mental imagery but not object mental imagery.     

Effects of informative peripheral cues on eye movements: Revisiting William James’ “derived attention”

Two experiments examined effects of peripheral information on the latency of saccadic eye movements. In Experiment 1, simple target stimuli were presented to the left or right visual field. Prior to each target, a pair of cue letters was presented for 40msec bilaterally. The relative location of the letters (W-S or S-W) was related to target location, but participants were not informed of this contingency. After a brief practice period, saccadic latencies were faster for targets at the likely location, as indicated by the letter pair. This derived peripheral cueing effect was related to participants' awareness of the relation between cue type and target location. Experiments 2A and 2B employed monocular viewing in order to compare performance across the nasal and temporal visual fields. The effect observed in Experiment 1 was confined to the nasal visual field. In a reflexive orienting condition, the effect of a unilateral letter cue was larger in the temporal visual field. It is concluded that the neurocognitive processes responsible for derived peripheral cueing are distinct from those involved in either reflexive or voluntary orienting.     

Non-Informative Effects of Stimuli Functioning as Cues

The category of a first stimulus (S₁) serving as a cue may allow a subject to predict the category of a second stimulus (S₂). However, a cue may have effects on RT to S₂ that are independent of those derived from its intended role as a predictor. These non-informative effects of a cue may add to or subtract from the benefits associated with its predictive function. Two experiments demonstrate that when S₁ is in the same category as S₂ (as is frequently the case for valid cues in cueing experiments) but provides no information about S₂, RT is slower than when S₁ is in a different category from S₂. It is suggested that this category relation effect arises because inhibition of a response to S₁ is still present when S₂ arrives and that, in some cueing experiments, it may subtract from the RT benefits derived from the cue as a predictor of S₂. Also, RT to a visual but not to an auditory S₂ was faster after an auditory S₁ than after a visual S₁. It is argued that this modality combination effect is consistent with the view that auditory signals are more alerting than visual ones and that this is another factor to be taken into account in the design of cueing and other experiments.     

Why does the gaze of others direct visual attention?

Viewing another person directing his or her gaze can produce automatic shifts of covert visual attention in the same direction. This holds true even when the task‐relevant target is much more likely to occur at the uncued location. These findings, along with other evidence, have been taken to suggest that gaze represents a “special” stimulus—the foundation of a social cognition system that can make inferences about the mental states of other people. However, gaze‐driven cueing effects could simply be due to spatial compatibility between cue and target. We compared the attentional effects of gaze shifts to a face with the tongue extended laterally to the left or right. When tongue direction was a nonpredictive cue, we found cueing effects from tongues that were indistinguishable from those produced by gaze. However, in contrast to previous findings with gaze, tongue cues did not overcome a validity manipulation in which targets were four times more likely to appear at the uncued location. We conclude that simple attentional cueing effects from gaze may be better explained by spatial compatibility, and that more complex, unique features of cueing from gaze may be better indices into perceptual systems specialized for social cognition.     

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.     

Contrast polarity of eyes modulates gaze‐cueing effect1

Two experiments using a modified Posner‐type visual cueing paradigm tested the prediction that detecting the darker region of the eyes of another's gaze triggers a reflexive orienting of the observer in the direction of the gaze. A target was presented in the left or right visual‐field following a gaze‐cue with positive or negative‐image polarity (Experiment 1). In Experiment 2, the polarity of the eyes was manipulated independently of the negative polarity of the face (eye‐positive or eye‐negative‐image polarity conditions). The results showed that the response to the target presented at the side the eyes gazed toward was faster than for the target presented at the other side in the positive polarity condition (Experiment 1), whereas, in the negative polarity condition, the gaze‐cuing effect was not found. In Experiment 2, in the eye‐negative condition, a reversed gaze‐cueing effect appeared, whereas in the eye‐positive polarity condition, a typical gaze‐cueing effect was obtained. These findings suggested that the reflexive orienting of the observer shifts toward the position indicated by the darker region of the other's eyes.     

视觉表象生成系统及其影响因素

视觉表象是在记忆基础上产生的类似知觉的信息表征, 也是人们在日常生活中不可或缺的心理活动之一。本综述介绍了该领域中比较有影响力的表象计算理论模型, 并进一步归纳了视觉表象生成系统的成分及其对应的神经基础。分析结果强调了初级视觉皮层作为“视觉缓冲器”是生成表象的主要机能结构, 以“视觉缓冲器”为基础的表象生成系统的机能受多重因素影响。本综述有助于对视觉表象生成系统形成全面的认识, 促进视觉表象实质的进一步研究。