Using real-world scenes as contextual cues for search

Research on contextual cueing has demonstrated that with simple arrays of letters and shapes, search for a target increases in efficiency as associations between a search target and its surrounding visual context are learned. We investigated whether the visual context afforded by repeated exposure to real-world scenes can also guide attention when the relationship between the scene and a target position is arbitrary. Observers searched for and identified a target letter embedded in photographs of real-world scenes. Although search time within novel scenes was consistent across trials, search time within repeated scenes decreased across repetitions. Unlike previous demonstrations of contextual cueing, however, memory for scene-target covariation was explicit. In subsequent memory tests, observers recognized repeated contexts more often than those that were presented once and displayed superior recall of target position within the repeated scenes. In addition, repetition of inverted scenes, which made the scene more difficult to identify, produced a markedly reduced rate of learning, suggesting semantic information concerning object and scene identity are used to guide attention.     

Object based implicit contextual learning: a study of eye movements

Implicit contextual cueing refers to a top-down mechanism in which visual search is facilitated by learned contextual features. In the current study we aimed to investigate the mechanism underlying implicit contextual learning using object information as a contextual cue. Therefore, we measured eye movements during an object-based contextual cueing task. We demonstrated that visual search is facilitated by repeated object information and that this reduction in response times is associated with shorter fixation durations. This indicates that by memorizing associations between objects in our environment we can recognize objects faster, thereby facilitating visual search.     

Contextual cueing of visual attention

Visual context information constrains what to expect and where to look, facilitating search for and recognition of objects embedded in complex displays. This article reviews a new paradigm called contextual cueing, which presents well-defined, novel visual contexts and aims to understand how contextual information is learned and how it guides the deployment of visual attention. In addition, the contextual cueing task is well suited to the study of the neural substrate of contextual learning. For example, amnesic patients with hippocampal damage are impaired in their learning of novel contextual information, even though learning in the contextual cueing task does not appear to rely on conscious retrieval of contextual memory traces. We argue that contextual information is important because it embodies invariant properties of the visual environment such as stable spatial layout information as well as object covariation information. Sensitivity to these statistical regularities allows us to interact more effectively with the visual world.     

真实场景视觉搜索中的背景线索效应特点与机制

背景线索效应揭示了个体在视觉搜索过程中对刺激之间具有的稳定空间关系（刺激间不变的相对空间位置）的学习能够提高搜索效率。本文基于经典背景线索效应在内隐习得空间布局的机制下结合真实场景视觉搜索的相关理论，对真实场景背景线索效应的实验范式、学习性质与内容进行归纳梳理，将真实场景视觉搜索中影响背景线索效应的视觉信息分为低水平物理特征及高水平语义信息两个维度进行论述。虽然当前研究涉及真实场景背景线索效应在不同场景维度信息的加工机制，但对于发挥作用的场景信息类别以及作用阶段还较少涉及，未来研究仍需进一步的探讨。     

Interaction between scene-based and array-based contextual cueing

Contextual cueing refers to the cueing of spatial attention by repeated spatial context. Previous studies have demonstrated distinctive properties of contextual cueing by background scenes and by an array of search items. Whereas scene-based contextual cueing reflects explicit learning of the scene–target association, array-based contextual cueing is supported primarily by implicit learning. In this study, we investigated the interaction between scene-based and array-based contextual cueing. Participants searched for a target that was predicted by both the background scene and the locations of distractor items. We tested three possible patterns of interaction: (1) The scene and the array could be learned independently, in which case cueing should be expressed even when only one cue was preserved; (2) the scene and array could be learned jointly, in which case cueing should occur only when both cues were preserved; (3) overshadowing might occur, in which case learning of the stronger cue should preclude learning of the weaker cue. In several experiments, we manipulated the nature of the contextual cues present during training and testing. We also tested explicit awareness of scenes, scene–target associations, and arrays. The results supported the overshadowing account: Specifically, scene-based contextual cueing precluded array-based contextual cueing when both were predictive of the location of a search target. We suggest that explicit, endogenous cues dominate over implicit cues in guiding spatial attention.     

Categorical implicit learning in real-world scenes: evidence from contextual cueing

The present study examined the extent to which learning mechanisms are deployed on semantic-categorical regularities during a visual searching within real-world scenes. The contextual cueing paradigm was used with photographs of indoor scenes in which the semantic category did or did not predict the target position on the screen. No evidence of a facilitation effect was observed in the predictive condition compared to the nonpredictive condition when participants were merely instructed to search for a target T or L (Experiment 1). However, a rapid contextual cueing effect occurred when each display containing the search target was preceded by a preview of the scene on which participants had to make a decision regarding the scene's category (Experiment 2). A follow-up explicit memory task indicated that this benefit resulted from implicit learning. Similar implicit contextual cueing effects were also obtained when the scene to categorize was different from the subsequent search scene (Experiment 3) and when a mere preview of the search scene preceded the visual searching (Experiment 4). These results suggested that if enhancing the processing of the scene was required with the present material, such implicit semantic learning can nevertheless take place when the category is task irrelevant.     

积极情绪提高背景线索学习的适应性

背景线索的学习缺乏适应性, 这种缺乏表现在两个方面：其一是难以在已习得的场景表征上捆绑一个新目标位置(Re-learning), 也就是场景表征的更新受阻; 其二是在习得一组场景表征后, 难以学习另一组全新场景(New-learning)。研究表明, 在旧场景表征上捆绑一个新目标位置的能力可能与注意范围大小有关, 而学习全新场景则需要重置学习功能。积极情绪可以有效扩大注意范围, 并改善对旧有认知模式的固着, 因此积极情绪启动将有可能提升背景线索学习的适应性。本研究采用效价为中性和积极的情绪性图片来启动对应的情绪, 探索旧场景捆绑新目标位置时和学习全新场景时, 背景线索的学习情况, 验证积极情绪是否可以提高背景线索学习中的适应性。实验发现, 积极情绪无法促进旧场景上捆绑新目标位置的背景线索学习(Re-learning), 但是可以促进全新场景的学习(New-learning)。该结果说明, 积极情绪可以提高被试的场景学习能力进而促进对全新场景的学习, 却无法减少由表征相似性引起的旧表征的自动检索, 进而无法改善旧表征的更新过程。     

Object-position binding in visual memory for natural scenes and object arrays

Nine experiments examined the means by which visual memory for individual objects is structured into a larger representation of a scene. Participants viewed images of natural scenes or object arrays in a change detection task requiring memory for the visual form of a single target object. In the test image, 2 properties of the stimulus were independently manipulated: the position of the target object and the spatial properties of the larger scene or array context. Memory performance was higher when the target object position remained the same from study to test. This same-position advantage was reduced or eliminated following contextual changes that disrupted the relative spatial relationships among contextual objects (context deletion, scrambling, and binding change) but was preserved following contextual change that did not disrupt relative spatial relationships (translation). Thus, episodic scene representations are formed through the binding of objects to scene locations, and object position is defined relative to a larger spatial representation coding the relative locations of contextual objects.     

Neural dynamics of object-based multifocal visual spatial attention and priming: object cueing, useful-field-of-view, and crowding

How are spatial and object attention coordinated to achieve rapid object learning and recognition during eye movement search? How do prefrontal priming and parietal spatial mechanisms interact to determine the reaction time costs of intra-object attention shifts, inter-object attention shifts, and shifts between visible objects and covertly cued locations? What factors underlie individual differences in the timing and frequency of such attentional shifts? How do transient and sustained spatial attentional mechanisms work and interact? How can volition, mediated via the basal ganglia, influence the span of spatial attention? A neural model is developed of how spatial attention in the where cortical stream coordinates view-invariant object category learning in the what cortical stream under free viewing conditions. The model simulates psychological data about the dynamics of covert attention priming and switching requiring multifocal attention without eye movements. The model predicts how “attentional shrouds” are formed when surface representations in cortical area V4 resonate with spatial attention in posterior parietal cortex (PPC) and prefrontal cortex (PFC), while shrouds compete among themselves for dominance. Winning shrouds support invariant object category learning, and active surface-shroud resonances support conscious surface perception and recognition. Attentive competition between multiple objects and cues simulates reaction-time data from the two-object cueing paradigm. The relative strength of sustained surface-driven and fast-transient motion-driven spatial attention controls individual differences in reaction time for invalid cues. Competition between surface-driven attentional shrouds controls individual differences in detection rate of peripheral targets in useful-field-of-view tasks. The model proposes how the strength of competition can be mediated, though learning or momentary changes in volition, by the basal ganglia. A new explanation of crowding shows how the cortical magnification factor, among other variables, can cause multiple object surfaces to share a single surface-shroud resonance, thereby preventing recognition of the individual objects.     

The role of meaning in contextual cueing: Evidence from chess expertise

In contextual cueing, the position of a search target is learned over repeated exposures to a visual display. The strength of this effect varies across stimulus types. For example, real-world scene contexts give rise to larger search benefits than contexts composed of letters or shapes. We investigated whether such differences in learning can be at least partially explained by the degree of semantic meaning associated with a context independently of the nature of the visual information available (which also varies across stimulus types). Chess boards served as the learning context as their meaningfulness depends on the observer's knowledge of the game. In Experiment 1, boards depicted actual game play, and search benefits for repeated boards were 4 times greater for experts than for novices. In Experiment 2, search benefits among experts were halved when less meaningful randomly generated boards were used. Thus, stimulus meaningfulness independently contributes to learning context–target associations.     

Attention dependency in implicit learning of repeated search context

How much attention is needed to produce implicit learning? Previous studies have found inconsistent results, with some implicit learning tasks requiring virtually no attention while others rely on attention. In this study we examine the degree of attentional dependency in implicit learning of repeated visual search context. Observers searched for a target among distractors that were either highly similar to the target or dissimilar to the target. We found that the size of contextual cueing was comparable from repetition of the two types of distractors, even though attention dwelled much longer on distractors highly similar to the target. We suggest that beyond a minimal amount, further increase in attentional dwell time does not contribute significantly to implicit learning of repeated search context.     

The role of meaning in contextual cueing: evidence from chess expertise

In contextual cueing, the position of a search target is learned over repeated exposures to a visual display. The strength of this effect varies across stimulus types. For example, real-world scene contexts give rise to larger search benefits than contexts composed of letters or shapes. We investigated whether such differences in learning can be at least partially explained by the degree of semantic meaning associated with a context independently of the nature of the visual information available (which also varies across stimulus types). Chess boards served as the learning context as their meaningfulness depends on the observer's knowledge of the game. In Experiment 1, boards depicted actual game play, and search benefits for repeated boards were 4 times greater for experts than for novices. In Experiment 2, search benefits among experts were halved when less meaningful randomly generated boards were used. Thus, stimulus meaningfulness independently contributes to learning context-target associations.     

Attention dependency in implicit learning of repeated search context

How much attention is needed to produce implicit learning? Previous studies have found inconsistent results, with some implicit learning tasks requiring virtually no attention while others rely on attention. In this study we examine the degree of attentional dependency in implicit learning of repeated visual search context. Observers searched for a target among distractors that were either highly similar to the target or dissimilar to the target. We found that the size of contextual cueing was comparable from repetition of the two types of distractors, even though attention dwelled much longer on distractors highly similar to the target. We suggest that beyond a minimal amount, further increase in attentional dwell time does not contribute significantly to implicit learning of repeated search context.     

空间工作记忆负载对真实场景情境提示效应的影响

重复的画面布局能够促进观察者对目标项的搜索 (情境提示效应)。本研究采用双任务范式,分别在视觉搜索任务的学习阶段 (实验2a) 和测验阶段 (实验2b) 加入空间工作记忆任务, 并与单任务基线 (实验1)进行比较, 考察空间工作记忆负载对真实场景搜索中情境线索学习和情境提示效应表达的影响。结果发现: 空间负载会增大学习阶段的情境提示效应量, 同时削弱测验阶段的情境提示效应量, 而不影响情境线索的外显提取。由此可见, 真实场景中情境线索的学习和提示效应的表达均会受到有限的工作记忆资源的影响, 但情境线索提取的外显性不变。     

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.     

Two (or three) is one too many: testing the flexibility of contextual cueing with multiple target locations

Visual search for a target object is facilitated when the object is repeatedly presented within an invariant context of surrounding items ("contextual cueing"; Chun & Jiang, Cognitive Psychology, 36, 28-71, 1998). The present study investigated whether such invariant contexts can cue more than one target location. In a series of three experiments, we showed that contextual cueing is significantly reduced when invariant contexts are paired with two rather than one possible target location, whereas no contextual cueing occurs with three distinct target locations. Closer data inspection revealed that one "dominant" target always exhibited substantially more contextual cueing than did the other, "minor" target(s), which caused negative contextual-cueing effects. However, minor targets could benefit from the invariant context when they were spatially close to the dominant target. In sum, our experiments suggest that contextual cueing can guide visual attention to a spatially limited region of the display, only enhancing the detection of targets presented inside that region.     

Contextual remapping in visual search after predictable target-location changes

Invariant spatial context can facilitate visual search. For instance, detection of a target is faster if it is presented within a repeatedly encountered, as compared to a novel, layout of nontargets, demonstrating a role of contextual learning for attentional guidance (‘contextual cueing’). Here, we investigated how context-based learning adapts to target location (and identity) changes. Three experiments were performed in which, in an initial learning phase, observers learned to associate a given context with a given target location. A subsequent test phase then introduced identity and/or location changes to the target. The results showed that contextual cueing could not compensate for target changes that were not ‘predictable’ (i.e. learnable). However, for predictable changes, contextual cueing remained effective even immediately after the change. These findings demonstrate that contextual cueing is adaptive to predictable target location changes. Under these conditions, learned contextual associations can be effectively ‘remapped’ to accommodate new task requirements.     

The effect of spatial and nonspatial contextual information on visual object memory

Recent research has found visual object memory can be stored as part of a larger scene representation rather than independently of scene context. The present study examined how spatial and nonspatial contextual information modulate visual object memory. Two experiments tested participants’ visual memory by using a change detection task in which a target object's orientation was either the same as it appeared during initial viewing or changed. In addition, we examined the effect of spatial and nonspatial contextual manipulations on change detection performance. The results revealed that visual object representations can be maintained reliably after viewing arrays of objects. Moreover, change detection performance was significantly higher when either spatial or nonspatial contextual information remained the same in the test image. We concluded that while processing complex visual stimuli such as object arrays, visual object memory can be stored as part of a comprehensive scene representation, and both spatial and nonspatial contextual changes modulate visual memory retrieval and comparison.     

Working memory dependence of spatial contextual cueing for visual search

When spatial stimulus configurations repeat in visual search, a search facilitation, resulting in shorter search times, can be observed that is due to incidental learning. This contextual cueing effect appears to be rather implicit, uncorrelated with observers’ explicit memory of display configurations. Nevertheless, as I review here, this search facilitation due to contextual cueing depends on visuospatial working memory resources, and it disappears when visuospatial working memory is loaded by a concurrent delayed match to sample task. However, the search facilitation immediately recovers for displays learnt under visuospatial working memory load when this load is removed in a subsequent test phase. Thus, latent learning of visuospatial configurations does not depend on visuospatial working memory, but the expression of learning, as memory‐guided search in repeated displays, does. This working memory dependence has also consequences for visual search with foveal vision loss, where top‐down controlled visual exploration strategies pose high demands on visuospatial working memory, in this way interfering with memory‐guided search in repeated displays. Converging evidence for the contribution of working memory to contextual cueing comes from neuroimaging data demonstrating that distinct cortical areas along the intraparietal sulcus as well as more ventral parieto‐occipital cortex are jointly activated by visual working memory and contextual cueing.     

Local and global contextual constraints on the identification of objects in scenes.

Objects likely to appear in a given real-world scene are frequently found to be easier to recognize. Two different sources of contextual information have been proposed as the basis for this effect: global scene background and individual companion objects. The present paper examines the relative importance of these two elements in explaining the context-sensitivity of object identification in full scenes. Specific sequences of object fixations were elicited during free scene exploration, while fixation times on designated target objects were recorded as a measure of ease of target identification. Episodic consistency between the target, the global scene background, and the object fixated just prior to the target (the prime), were manipulated orthogonally. Target fixation times were examined for effects of prime and background. Analyses show effects of both factors, which are modulated by the chronology and spatial extent of scene exploration. The results are discussed in terms of their implications for a model of visual object recognition in the context of real-world scenes.