多通道变化盲:理论、方法与进展

人们在特定条件下通常难以探测到事物的变化,这种现象发生在视、听、触感觉通道分别称为变化盲视、变话盲听和变化盲触。文章主要对以下四个方面进行详细的探讨:变化盲视及视觉表征理论、变化盲听及听觉信息加工机制、变化盲触及体表空间表征、多通道变化盲及空间注意和空间表征跨通道一致性本质。此外,文章还对多通道变化盲的理论深度和拓展方向及相关应用研究进行了展望。     

变化盲视的最新研究进展

变化盲视指观察者不能探测到客体或情境中的变化 ,是近十年以来认知心理学的研究热点之一。变化盲视可发生在各种实验条件下。例如 ,在扫视、眨眼、电影镜头切换时发生的变化以及真实情景的交互作用中发生的变化 ,观察者都有可能探测不到。本文介绍了近年来对于变化盲视的研究成果 ,包括经常使用的实验范式和对这个现象的解释等     

变化知觉的另一面——变化盲

人们经常会探测不到事物的变化,这种现象被称为变化盲（change blindness）,它和变化觉察是变化知觉的两个面。对变化盲的研究主要集中以下几个方面：对变化盲现象产生的原因辨析以及从刺激属性和注意广度、知识经验、个体差异、文化背景等分析变化盲的影响因素;近几年来内隐变化觉察也引起研究者的争论和重视;此外,对变化盲的多（跨）通道和错误元认知研究也成为一种新的研究动向。同时,变化盲研究在其表征机制、加工方式以及内隐变化觉察等方面尚存在争议,变化盲的错误元认知研究以及变化盲的认知神经心理研究则是此领域的薄弱环节。     

注意和工作记忆提取对变化盲视的影响

变化盲视是指观察者不能探测到视觉情境中明显的变化。本研究采用线索提示范式考察了注意和工作记忆提取对变化盲视的影响。结果发现,前置有效线索虽然不能缩短变化探测的时间,但可以降低变化盲视发生的概率,而后置有效线索既不能缩短变化探测的时间,也不能降低变化盲视的发生概率。结论表明,注意对变化盲视有显著影响,但工作记忆提取对变化盲视的影响不显著。     

内隐觉察的行为和神经活动特征

变化盲视是指在某些条件下人们往往觉察不到视觉场景中实质性的改变。最近研究表明,变化盲视发生时个体虽然不能有意识地报告变化,但却能无意识地对变化刺激进行加工和反应,也就是产生了内隐觉察。内隐觉察能够引导注意、影响反应速度。与觉察和无觉察相比,内隐觉察的眼动模式具有鲜明的特征。与无变化试次相比,盲视试次可以观察到显著的脑电活动变化以及不同的脑区激活。内隐觉察的研究虽然取得了丰富的成果,但也还存在着一些需要明确和解决的问题,如左侧前额叶在内隐觉察中的作用,以及如何将没有视觉干扰的范式应用到变化觉察的神经活动测量中等。     

注意捕获的另一扇窗户——无意视盲

观察者集中注意于某个物体或事件的时候,他们经常不能觉察到显著的、与众不同的物体,这种现象被称为“无意视盲”（Inattentional Blindness）。在无意视盲研究中,存在两类实验范式——静态无意视盲和动态无意视盲研究范式。首先,从刺激的感觉显著性、认知显著性、心理工作负荷、定势和期望以及加工能力等方面分析了影响无意视盲的因素;其次,对无意视盲和无意遗忘的争议以及无意视盲是“全或无”还是连续谱的争议也进行了总结;最后,从无意视盲角度出发探讨了内隐注意捕获和外显注意捕获之间的关系     

非预想刺激的运动速率对无意视盲的影响

无意视盲是指由于对某些事物的专注而导致的眼前对象被忽视的现象。它受到诸如非预想刺激的位置、大小、颜色; 非预想刺激与注意刺激之间的关系; 被试的年龄、专业知识、加工能力等诸多因素的影响。本文通过改进的MR范式考察了“等时”和“等距”条件下非预想刺激的运动速率对无意视盲的影响。实验结果显示: (1)非预想刺激的运动速率和其呈现时间对无意视盲的比率有显著影响; (2)在一定的呈现时间范围内, 视盲率随运动速率的升高而降低, 但当维持相等的运动距离时, 视盲率没有显著变化; (3)当呈现时间超出一定范围时, 运动速率对无意视盲的影响急剧减小, 即呈现时间制约着运动速率对无意视盲的影响, 两者间呈倒U型曲线关系。文末就实验结果进行了详细分析和讨论。     

情绪诱发的视盲：一种独特的功能性视盲

功能性视盲是指由于某种原因导致正常的视觉系统出现视觉觉察丧失的现象, 例如变化知盲、注意瞬脱等都属于功能性视盲。情绪诱发的视盲指的是一个与任务无关的情绪性刺激的呈现吸引了注意以致个体无法对快速呈现的靶刺激有所觉察的现象。与注意瞬脱特别是情绪性注意瞬脱相比, 情绪诱发的视盲是以情绪刺激为干扰刺激, 考察情绪刺激如何以自下而上的方式吸引注意并干扰靶刺激的加工, 因此有着自己的特点：它没有lag1节省现象, 也没有像注意瞬脱那样严格的时间窗口限制, 不受干扰刺激与靶刺激物理特征相似程度的限制, 在心理机制上属于早期知觉阶段的加工竞争等等。情绪诱发的视盲表明情绪对注意在时间和空间两个维度上都有吸引或干扰作用。未来可以从考察神经机制、了解影响因素等多方面深化此领域的研究。     

意外刺激的意义性及位置对大学生无意视盲的影响

无意视盲是指由于专注于某项任务而对视野中的其他事物视而不见的现象,它同时受意外刺激低水平的物理特性、语义相关性以及观察者自身因素的影响。无意视盲是联系知觉、意识和注意的重要桥梁。本文采用静态的无意视盲范式,随机选取80名在校大学生为被试,同时考察了意外刺激的位置和意义性对无意视盲的影响。结果表明:(1)意外刺激的呈现位置对无意视盲没有显著的影响,呈现在外周和中央的探测率无显著差异。说明无意视盲可能是受基于注意区域而不是基于注视点的位置因素的影响;(2)意外刺激的意义性对无意视盲有显著的影响,相比于无意义刺激,有意义的卡通笑脸不管呈现在中央还是外周,都更易获得探测。     

工作记忆内容对无意视盲的改善作用

无意视盲是注意捕获失败的一种现象.研究发现:工作记忆内容对视觉注意的引导可以影响视觉注意的捕获.本研究以此为基础探讨了工作记忆内容能否影响无意视盲.本研究采用了静态无意视盲典型范式,通过两个实验分别探讨了工作记忆对无意视盲的引导作用以及在不同知觉负荷下引导作用的自动性,进而研究工作记忆内容对无意视盲的改善作用.实验1结果表明,当非期望刺激与工作记忆内容属于同一类别时,对非期望刺激的觉察率显著高于当非期望刺激与工作记忆内容不属于同一类别的情况,说明在纯语义的水平上工作记忆内容可以引导视觉注意捕获,进而改善无意视盲.实验2发现,当知觉负荷由低到高变化时,非期望刺激与工作记忆内容同类属时,觉察率无显著变化,说明工作记忆内容对无意视盲引导不受知觉负荷的调节,是一种自动化的过程.     

Evidence for preserved representations in change blindness

People often fail to detect large changes to scenes, provided that the changes occur during a visual disruption. This phenomenon, known as "change blindness," occurs both in the laboratory and in real-world situations in which changes occur unexpectedly. The pervasiveness of the inability to detect changes is consistent with the theoretical notion that we internally represent relatively little information from our visual world from one glance at a scene to the next. However, evidence for change blindness does not necessarily imply the absence of such a representation---people could also miss changes if they fail to compare an existing representation of the pre-change scene to the post-change scene. In three experiments, we show that people often do have a representation of some aspects of the pre-change scene even when they fail to report the change. And, in fact, they appear to "discover" this memory and can explicitly report details of a changed object in response to probing questions. The results of these real-world change detection studies are discussed in the context of broader claims about change blindness.     

False predictions about the detectability of visual changes: the role of beliefs about attention,memory, and the continuity of attended objects in causing change blindness blindness

Recently, a number of experiments have emphasized the degree to which subjects fail to detect large changes in visual scenes. This finding, referred to as "change blindness," is often considered surprising because many people have the intuition that such changes should be easy to detect. documented this intuition by showing that the majority of subjects believe they would notice changes that are actually very rarely detected. Thus subjects exhibit a metacognitive error we refer to as "change blindness blindness." Here, we test whether CBB is caused by a misestimation of the perceptual experience associated with visual changes and show that it persists even when the pre- and postchange views are separated by long delays. In addition, subjects overestimate their change detection ability both when the relevant changes are illustrated by still pictures, and when they are illustrated using videos showing the changes occurring in real time. We conclude that CBB is a robust phenomenon that cannot be accounted for by failure to understand the specific perceptual experience associated with a change.     

Change deafness for simultaneous voices

Apparent changes in auditory scenes are often unnoticed. This change deafness phenomenon was examined in auditory scenes that comprise human voices. In two experiments, listeners were required to detect changes between two auditory scenes comprising two, three, and four talkers who voiced four‐syllable words. One of the voices in the first scene was randomly selected and was replaced with a new word in change trials. The rationale was that higher stimulus familiarity conferred by human voices compared to other everyday sounds, together with encoding and memory advantages for verbal stimuli and the modular processing of speech in auditory processing, should positively influence the change detection efficiency, and the change deafness phenomenon should not be observed when listeners are explicitly required to detect the obvious changes. Contrary to the prediction, change deafness was significantly observed in three‐ and four‐talker conditions. This indicates that change deafness occurs in listeners even for highly familiar stimuli. This suggests the limited ability for perceptual organization of auditory scenes comprising even a relatively small number of voices (three or four).     

Current Approaches to Change Blindness

Across saccades, blinks, blank screens, movie cuts, and other interruptions, observers fail to detect substantial changes to the visual details of objects and scenes. This inability to spot changes (“change blindness”) is the focus of this special issue of Visual Cognition. This introductory paper briefly reviews recent studies of change blindness, noting the relation of these findings to earlier research and discussing the inferences we can draw from them. Most explanations of change blindness assume that we fail to detect changes because the changed display masks or overwrites the initial display. Here I draw a distinction between intentional and incidental change detection tasks and consider how alternatives to the “overwriting” explanation may provide better explanations for change blindness.     

The scene and the unseen: Manipulating photographs for experiments on change blindness and scene memory

The change blindness paradigm, in which participants often fail to notice substantial changes in a scene, is a popular tool for studying scene perception, visual memory, and the link between awareness and attention. Some of the most striking and popular examples of change blindness have been demonstrated with digital photographs of natural scenes; in most studies, however, much simpler displays, such as abstract stimuli or “free-floating” objects, are typically used. Although simple displays have undeniable advantages, natural scenes remain a very useful and attractive stimulus for change blindness research. To assist researchers interested in using natural-scene stimuli in change blindness experiments, we provide here a step-by-step tutorial on how to produce changes in natural-scene images with a freely available image-processing tool (GIMP). We explain how changes in a scene can be made by deleting objects or relocating them within the scene or by changing the color of an object, in just a few simple steps. We also explain how the physical properties of such changes can be analyzed using GIMP and MATLAB (a high-level scientific programming tool). Finally, we present an experiment confirming that scenes manipulated according to our guidelines are effective in inducing change blindness and demonstrating the relationship between change blindness and the physical properties of the change and inter-individual differences in performance measures. We expect that this tutorial will be useful for researchers interested in studying the mechanisms of change blindness, attention, or visual memory using natural scenes.     

The effect of display timing on change blindness in pigeons (Columba livia)

Change blindness is a phenomenon in which even obvious changes in a visual scene may go unnoticed. Recent research has indicated that this phenomenon may not be exclusive to humans. Two experiments investigated change blindness in pigeons, using a variant of the widely‐used flicker task to investigate the influence of display timing on change blindness. Results indicate that the duration of time during which a stimulus display is visible influences change detection accuracy, with the effect due to additional search time. The results are discussed in relation to the value of comparative cognition and cross‐species investigations of behavior.     

Gorillas in our midst: sustained inattentional blindness for dynamic events

With each eye fixation, we experience a richly detailed visual world. Yet recent work on visual integration and change direction reveals that we are surprisingly unaware of the details of our environment from one view to the next: we often do not detect large changes to objects and scenes ('change blindness'). Furthermore, without attention, we may not even perceive objects ('inattentional blindness'). Taken together, these findings suggest that we perceive and remember only those objects and details that receive focused attention. In this paper, we briefly review and discuss evidence for these cognitive forms of 'blindness'. We then present a new study that builds on classic studies of divided visual attention to examine inattentional blindness for complex objects and events in dynamic scenes. Our results suggest that the likelihood of noticing an unexpected object depends on the similarity of that object to other objects in the display and on how difficult the priming monitoring task is. Interestingly, spatial proximity of the critical unattended object to attended locations does not appear to affect detection, suggesting that observers attend to objects and events, not spatial positions. We discuss the implications of these results for visual representations and awareness of our visual environment.