Spatio-temporal working-memory and short-term object-location tasks use different memory mechanisms

Spatial short-term memory for objects' locations was investigated in a spatial relocation task. During maintenance, dynamic visual noise or spatial tapping were administered as visual or spatial secondary tasks, respectively. Because memory for location should tap the visual component of working memory, a visual but not a spatial secondary task should impair location memory. In fact, neither of the tasks impaired memory (Experiment 1), although the expected dissociation between visual and spatial components was clearly confirmed for a spatio-temporal main task (Corsi test) (Experiment 2). We then contrasted location memory for pictures of objects and of nonsense figures under visual interference. Real objects were relocated much better than nonsense figures, and visual noise was again ineffective (Experiment 3). When spatial tapping was combined with the same material (Experiment 3a), again no influence on memory for locations of objects was observed and only a small influence on remembering nonsense figures. We suggest that the Corsi and the relocation VSWM-tasks use different memory mechanisms. The configuration of objects is reconstructed from perceptual records in an episodic buffer, provided by the same structures that enable visual memory after longer intervals. Rehearsal is not necessary for the persistence of these traces. In contrast, in the Corsi task remembering, a temporal sequence across homogeneous locations needs spatio-temporal marking and therefore active rehearsal of the locations by shifting spatial attention. A spatially demanding secondary task during retention interrupts this rehearsal.     

Representation of dynamic spatial configurations in visual short-term memory

Locations of multiple stationary objects are represented on the basis of their global spatial configuration in visual short-term memory (VSTM). Once objects move individually, they form a global spatial configuration with varying spatial inter-object relations over time. The representation of such dynamic spatial configurations in VSTM was investigated in six experiments. Participants memorized a scene with six moving and/or stationary objects and performed a location change detection task for one object specified during the probing phase. The spatial configuration of the objects was manipulated between memory phase and probing phase. Full spatial configurations showing all objects caused higher change detection performance than did no or partial spatial configurations for static and dynamic scenes. The representation of dynamic scenes in VSTM is therefore also based on their global spatial configuration. The variation of the spatiotemporal features of the objects demonstrated that spatiotemporal features of dynamic spatial configurations are represented in VSTM. The presentation of conflicting spatiotemporal cues interfered with memory retrieval. However, missing or conforming spatiotemporal cues triggered memory retrieval of dynamic spatial configurations. The configurational representation of stationary and moving objects was based on a single spatial configuration, indicating that static spatial configurations are a special case of dynamic spatial configurations.     

Selective learning of spatial configuration and object identity in visual search

To conduct an efficient visual search, visual attention must be guided to a target appropriately. Previous studies have suggested that attention can be quickly guided to a target when the spatial configurations of search objects or the object identities have been repeated. This phenomenon is termed contextual cuing. In this study, we investigated the effect of learning spatial configurations, object identities, and a combination of both configurations and identities on visual search. The results indicated that participants could learn the contexts of spatial configurations, but not of object identities, even when both configurations and identities were completely correlated (Experiment 1). On the other hand, when only object identities were repeated, an effect of identity learning could be observed (Experiment 2). Furthermore, an additive effect of configuration learning and identity learning was observed when, in some trials, each context was the relevant cue for predicting the target (Experiment 3). Participants could learn only the context that was associated with target location (Experiment 4). These findings indicate that when multiple contexts are redundant, contextual learning occurs selectively, depending on the predictability of the target location.     

不同空间构型下邻近性对视觉工作记忆中相似性效应的影响

相似性对视觉工作记忆表征的促进被称为相似性效应。以相似项目间的距离和是否插入其他项目改变邻近性,并操纵记忆项空间构型有序性,探讨邻近性对相似性效应的影响。结果发现,不同空间构型和邻近性条件下相似项目的记忆正确率高于非相似项目;在空间构型有序下,相似项目距离远时,插入其他项目时的相似性效应值低于不插入,而空间构型无序下未发现显著差异。这表明相似性促进视觉工作记忆表征,空间构型在邻近性对相似性效应的影响中起重要作用。     

Discrimination training of mirror-image stimuli with a delayed-prompt technique: some critical dimensions of extra-stimulus prompts

Research on fading and delay procedures has shown that extra-stimulus prompts frequently fail to help children learn difficult discriminations. The present study analyzed two delay conditions for an extra-stimulus prompt to help preschoolers discriminate mirror-image stimuli as a function of the configurations and locations of the prompts. All subjects were selected on their ability to discriminate the task stimuli in the presence of a third stimulus, a replica of the S+ and an arrow pointing to that stimulus; and on their inability to do so without these stimuli. Experiments 1 and 2 compared these prompt configurations (S+ replica, arrow) when presented equidistant from the task stimuli. Experiment 3 analyzed the contribution of the replica configuration in terms of its location, in between stimuli or immediately above the S+. Experiment 4 investigated the extent to which the results of the previous experiments could be influenced by the methodology for the assessment of prompt control. The results consistently demonstrated that most subjects did not learn the task unless the extra-stimulus prompt had the same configuration as the S+ and was located equidistant from both task stimuli.     

The effect of line configuration on perceived numerosity of dotted lines

Estimates of the number of objects in a line are made in many different situations. This paper demonstrates that besides the actual number of dots, aspects of line configuration affect the perceived numerosity of dotted lines. Experiment 1 provides evidence that the highly studied “clutter effect” in distance perception research replicates to the numerosity domain so that lines made up of more segments are perceived to contain more dots. Experiments 2–5 provide nomological validity for the recently proposed “direct distance” effect in distance perceptions by showing that numerosity perceptions are higher the greater the euclidean length between the line end points and by manipulating euclidean length in three orthogonal ways: the relative length of segments (Experiment 2), the angle between segments (Experiment 3), and the general direction of segments (Experiment 4). Experiment 5 conceptually replicates the results of Experiments 2–4 utilizing stimuli-based versus memory-based judgments and a discrimination task. Experiments 6 and 7 extend the research on spatial perception by demonstrating that the use of euclidean length as a source of information is inversely related to line width, with width varied through clutter (Experiment 6) and total line length (Experiment 7). Overall, the results demonstrate that the robustness of the euclidean length effect is contingent on the salience of alternative spatial heuristics-specifically, euclidean width. Theoretical implications are discussed.     

Investigating the visual span in comparative search: the effects of task difficulty and divided attention

In three experiments, participants' visual span was measured in a comparative visual search task in which they had to detect a local match or mismatch between two displays presented side by side. Experiment 1 manipulated the difficulty of the comparative visual search task by contrasting a mismatch detection task with a substantially more difficult match detection task. In Experiment 2, participants were tested in a single-task condition involving only the visual task and a dual-task condition in which they concurrently performed an auditory task. Finally, in Experiment 3, participants performed two dual-task conditions, which differed in the difficulty of the concurrent auditory task. Both the comparative search task difficulty (Experiment 1) and the divided attention manipulation (Experiments 2 and 3) produced strong effects on visual span size.     

Organization of visual short-term memory

The authors examined the organization of visual short-term memory (VSTM). Using a change-detection task, they reported that VSTM stores relational information between individual items. This relational processing is mediated by the organization of items into spatial configurations. The spatial configuration of visual objects is important for VSTM of spatial locations, colors, and shapes. When color VSTM is compared with location VSTM, spatial configuration plays an integral role because configuration is important for color VSTM, whereas color is not important for location VSTM. The authors also examined the role of attention and found that the formation of configuration is modulated by both top-down and bottom-up attentional factors. In summary, the authors proposed that VSTM stores the relational information of individual visual items on the basis of global spatial configuration.     

物体拓扑性质对背景线索效应的影响及其加工机制

背景线索效应是指在视觉搜索中由于场景的重复曝光而产生的行为便利。而以往研究关注于刺激的欧式性质所代表的属性信息对背景线索效应的影响, 然而在视知觉加工过程中扮演重要角色的拓扑性质对背景线索效应的影响仍缺乏相关实证研究。因此, 研究采用视觉搜索任务, 通过操控不同场景中刺激的拓扑性质或欧式性质的变化, 考察拓扑性质与欧式性质两种属性信息对背景线索效应的调制。结果发现：(1)拓扑性质和欧式性质与目标之间的联结关系均可促进行为反应, 获得背景线索效应; (2)视觉学习机制对拓扑性质的重复性更加敏感, 并且拓扑性质与目标之间联结关系的稳定性相对于欧式性质与目标之间的联结关系稳定性对于背景线索效应的获得具有更为重要的意义。     

Contextual cuing based on spatial arrangement of color

Previous studies have demonstrated that, in visual search, repetition of a target's "context" significantly improves search performance (contextual cuing; Chun & Jiang, 1998). Context in those studies was defined as either spatial configuration or featural combination. In the present work, we demonstrate that repeating the spatial arrangement of object colors (conjunction of spatial configuration and featural combination) also leads to contextual cuing (Experiment 1). Experiments 2 and 3 rule out the possibility that the contextual cuing we find in Experiment 1 is caused only by the spatial configuration of color patches. Experiment 4 rules out the possibility that it is caused only by featural combination. Experiments 5 and 6 demonstrate that color-arrangement-based contextual cuing is an unconscious process. Experiments 7 and 8 demonstrate that contextual cuing seems to be more effective onchromatic (hue) variation than on achromatic (luminance) variation. In sum, our results demonstrate that contextual cuing is not merely associated learning in separate domains; it is a more integrated process than has perhaps been appreciated.     

The influence of expertise and of physical complexity on visual short-term memory consolidation

We investigated whether the expertise of a perceiver and the physical complexity of a stimulus influence consolidation of visual short-term memory (VSTM) in a S1-S2 (Stimulus 1-Stimulus 2) change detection task. Consolidation is assumed to make transient perceptual representations in VSTM more durable, and it is investigated by postexposure of a mask shortly after offset of the perceived stimulus (S1; 17 to 483?ms). We presented colours, Chinese characters, pseudocharacters, and novel symbols to novices (Germans) or experts of Chinese language (Chinese readers). Physical complexity was manipulated by the number of strokes. Unfamiliar material was remembered worse than familiar material (Experiments 1, 2, and 3). For novices the absolute VSTM performance was better for physically simple than for complex material, whereas for experts the complexity did not matter-Chinese readers memorized Chinese characters (Experiment 3). Articulatory suppression did not change these effects (Experiment 2). We always observed a strong effect of SOA, but this effect was influenced neither by physical complexity nor by expertise; only the length of the interstimulus interval between S1 and the mask was relevant. This was observed even with short stimulus onset asynchrony (SOA) of 100?ms (Experiment 2) and in comparing colours and characters (Experiment 5). However, masks impaired memory if they were presented at the locations of the to-be-memorized items, but not beside them-that is, interference was location-based (Experiment 6). We explain the effect of SOA by the assumption that it takes time to stop encoding of information presented at item locations with the offset of S1. The increasing resistance against interference by irrelevant material appears as consolidation of S1.     

文本表述结构对空间维度非线索更新的影响

采用实时窗口阅读技术,探讨阅读中文本表述结构在情境模型空间维度非线索更新中的作用。实验一结果表明,阅读中,如果文本叙述中采用以人为参照的描述方式,那么可以促进相应空间设置内物体的实时更新。实验二考察了空间设置不同程度的描述对空间信息加工中的影响,结果发现,相对于对空间设置的简单描述,在文本中对空间设置进行精细阐述更有利于情境模型空间维度非线索更新的达成。     

Rats form cognitive maps from spatial configurations of proximal arm cues in an enclosed 4-arm radial maze

Rats were trained to select a final, remaining baited arm following a 6- to 10-min delay following their entries into three experimenter-selected baited arms in an enclosed 4-arm radial maze containing different proximally cued arms. Rats’ accuracy in selecting the remaining baited arm was disrupted when the spatial configuration of arm cues was randomly varied over trials following initial training with one configuration in Experiment 1. In Experiment 2, the same rats acquired this task with the original and a new configuration of the same arm cues when each consistently occurred at a specific time of day (one in the morning, the other in the afternoon). Randomly varying the temporal presentations of these configurations following acquisition disrupted rats’ choice accuracy more within the new than the original configuration. Other rats in Experiment 3 learned this task with two configurations containing different types of arm cues (full arm inserts, objects at the arm entrances). When required to relearn this task with recombined configurations of pairs of arm cues from of each configuration, only rats presented pairs of arms arranged differently from that in their original configurations were unable to reacquire the task. Together these results support a cognitive map hypothesis more than a proximal arm cue list hypothesis. These findings were discussed in terms of recent versions of cognitive map theory (Benhamou, 1998; Poucet, 1993) and the possible limits of such processing (Roberts, 2001).     

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.     

The properties of object representations constructed during visual search in natural scenes

To investigate properties of object representations constructed during a visual search task, we manipulated the proportion of trials/task within a block: In a search-frequent block, 80% of trials were search tasks; remaining trials presented a memory task; in a memory-frequent block, this proportion was reversed. In the search task, participants searched for a toy car (Experiments 1 and 2) or a T-shape object (Experiment 3). In the memory task, participants had to memorize objects in a scene. Memory performance was worse in the search-frequent block than in the memory-frequent block in Experiments 1 and 3, but not in Experiment 2 (token change in Experiment 1; type change in Experiments 2 and 3). Experiment 4 demonstrated that lower performance in the search-frequent block was not due to eye-movement behaviour. Results suggest that object representations constructed during visual search are different from those constructed during memorization and they are modulated by type of target.     

Continuous visual cues trigger automatic spatial target updating in dynamic scenes

Dynamic tasks often require fast adaptations to new viewpoints. It has been shown that automatic spatial updating is triggered by proprioceptive motion cues. Here, we demonstrate that purely visual cues are sufficient to trigger automatic updating. In five experiments, we examined spatial updating in a dynamic attention task in which participants had to track three objects across scene rotations that occurred while the objects were temporarily invisible. The objects moved on a floor plane acting as a reference frame and unpredictably either were relocated when reference frame rotations occurred or remained in place. Although participants were aware of this dissociation they were unable to ignore continuous visual cues about scene rotations (Experiments 1a and 1b). This even held when common rotations of floor plane and objects were less likely than a dissociated rotation (Experiments 2a and 2b). However, identifying only the spatial reference direction was not sufficient to trigger updating (Experiment 3). Thus we conclude that automatic spatial target updating occurs with pure visual information.     

Attending to the parts of a single object: part-based selection limitations

Studies of object-based attention have demonstrated poorer performance in dividing attention between two objects in a scene than in focusing attention on a single object. However, objects often are composed of several parts, and parts are central to theories of object recognition. Are parts also important for visual attention? That is, can attention be limited in the number of parts processed simultaneously? We addressed this question in four experiments. In Experiments 1 and 2, participants reported two attributes that appeared on the same part or on different parts of a single multipart object. Participants were more accurate in reporting the attributes on the same part than attributes on different parts. This part-based effect was not influenced by the spatial distance between the parts, ruling out a simple spatial attention interpretation of our results. A control study demonstrated that our spatial manipulation was sufficient to observe shifts of spatial attention. This study revealed an effect of spatial distance, indicating that our spatial manipulation was adequate for observing spatial attention. The absence of a distance effect in Experiments 1 and 2 suggests that part-based attention may not rely entirely on simple shifts of spatial attention. Finally, in Experiment 4 we found evidence for part-based attention, using stimuli controlled for the distance between the parts of an object. The results of these experiments indicate that visual attention can selectively process the parts of an object. We discuss the relationship between parts and objects and the locus of part-based attentional selection.     

自我信息对知觉选择中整体优先性的调控作用

已有研究表明个人重要信息调控高级认知加工过程, 如面孔识别、记忆、思维等。本研究的三项实验系统地测量了个人重要信息对知觉选择的影响。采用最近发展的自我连接学习范式, 让中性几何图形与不同人(自我、朋友、陌生人)建立联系; 图形-标签连接完成后, 以复合图形(局部小图形组成整体大图形)作为实验刺激, 被试完成整体/局部图形判断任务, 通过评估个体对具有不同社会意义图形(目标vs.分心物水平)的感知差异, 测量个人重要信息对知觉选择的调控作用。结果发现, 与他人相关图形相比, 自我相关图形作为分心物调控整体优先效应, 这种效应一致地发生在整体和局部水平上, 并且不受注意任务的影响。这些结果提示社会信息对认知的调控作用发生在视觉选择水平上。     

Effects of pointing compared with naming and observing during encoding on item and source memory in young and older adults

Research showed that source memory functioning declines with ageing. Evidence suggests that encoding visual stimuli with manual pointing in addition to visual observation can have a positive effect on spatial memory compared with visual observation only. The present study investigated whether pointing at picture locations during encoding would lead to better spatial source memory than naming (Experiment 1) and visual observation only (Experiment 2) in young and older adults. Experiment 3 investigated whether response modality during the test phase would influence spatial source memory performance. Experiments 1 and 2 supported the hypothesis that pointing during encoding led to better source memory for picture locations than naming or observation only. Young adults outperformed older adults on the source memory but not the item memory task in both Experiments 1 and 2. In Experiments 1 and 2, participants manually responded in the test phase. Experiment 3 showed that if participants had to verbally respond in the test phase, the positive effect of pointing compared with naming during encoding disappeared. The results suggest that pointing at picture locations during encoding can enhance spatial source memory in both young and older adults, but only if the response modality is congruent in the test phase.