在不同注意定向条件下是否出现返回抑制的知觉优先

返回控制中的知觉优先是指相对于非线索化位置,线索化位置的刺激被优先知觉到的现象。研究采用时序判断方法对不同注意定向下返回抑制的知觉优先现象进行了两个实验。实验１采用连续线索化的安排,发现当注意从线索化位置移开后知觉优先仍然存在;实验２采用同时呈现双线索的安排发现知觉优先也存在。     

基于N2pc成分的视觉空间注意功能老化机制

视觉空间注意是人的一种基本认知功能,对老年人的生活有重要影响。N2pc作为一种与注意选择相关的ERP成分,可以反映注意资源在空间上的分配,是研究视觉空间注意的一个良好指标。本文对此前基于N2pc成分的注意功能老化研究进行了综述。前人研究主要采用视觉搜索范式与空间线索范式。采用视觉搜索范式的研究发现,当目标周围有干扰子时,目标诱发的N2pc在老年人中振幅减小,潜伏期延迟,同时在行为上老年人与年轻人相比,正确率更低,反应时更长; 当目标周围无干扰子时,目标诱发的N2pc振幅老年人与年轻人相当或比年轻人更大,老年人的正确率与年轻人无显著差异。采用空间线索范式的研究发现,与目标无相同特征的线索奇异子(singleton cue)不会诱发N2pc,与目标有相同特征的线索奇异子诱发的N2pc未表现出年龄差异,差异体现在一种反映抑制的ERP成分—Pd上(年轻人有Pd而老年人没有),此时老年人在行为上表现出比年轻人更强的空间线索效应。这些研究共同说明,视觉空间注意功能的老化是一个复杂的过程,涉及到搜索目标时注意分配速度的减慢,对干扰子抑制能力的下降以及基于特征的注意捕获能力的良好保持。     

儿童、青年与老年人在知觉和高阶元认知监控上的年龄差异

元认知是以监测和控制为核心的动态调节活动。本研究以9岁儿童、年轻人和老年人为研究对象，分别采用选点任务和词对学习任务，在知觉元认知和高阶元认知层次考察元认知监测和控制及其关系随年龄变化的特点。结果显示：(1)儿童的知觉元认知和高阶元认知监控能力大都低于年轻人；(2)老年人的知觉元认知能力与年轻人相似，但高阶元认知能力则低于年轻人；(3)老年人和年轻人一样能够在记忆监测中利用控制线索，而9岁儿童尚未表现出这种能力。本研究从发展的角度，支持了知觉元认知与高阶元认知能力具有领域特殊性的理论假设，并对监测和控制的关系发展进行了讨论。     

注视方向的知觉对注视追随行为的影响

他人的注视线索可诱导观察者将注意自动地转移到该线索所指示的方向上去(注视追随), 但仍不清楚注视方向的知觉在注视追随中起到何种作用。本研究结合注视适应和注视线索提示范式发现：知觉到的注视线索角度越大, 其线索提示效应越强; 知觉适应后被试判断注视方向的准确性下降, 注视线索引起的注意转移量显著减少。可见, 对注视方向的知觉能直接影响注视追随行为, 而注视方向抽取受到刺激显著性(注视角度)和知觉适应等因素的调节。这提示：在意识状态下, 注视知觉与注视追随存在直接联系, 即可能存在从注视知觉系统到注意转移系统的皮层加工通路; 注视追随并非纯粹的反射式加工, 它受自上而下知觉经验的调节。     

空间选择性注意在上下视野间的转移

本实验研究空间选择性注意在上下视野间的转移及其是否受知觉空间的影响。实验采用Posner的位置线索化实验范式和两种深度线索背景,测量分辨任务的反应时(RTs)。实验发现:线索有效时的反应时比线索无效时的反应时短,而且线索对上视野刺激的反应时的影响较大。知觉空间中的深度线索对于注意在上下视野中转移没有显著影响。这些结果表明,空间选择性注意在上下视野转移存在不对称性,并且主要由物理空间决定。     

不同线索化条件下返回抑制时程年老化研究

采用线索-靶子范式,比较了单线索和双线索条件下年轻人和老年人返回抑制时间进程的发展趋势。实验1采用单线索化程序和觉察任务,SOA分为9种水平;实验2采用双线索化程序和觉察任务,SOA分为10种水平。结果显示：线索化阶段的注意分配和年龄对返回抑制的时程发展产生影响。（1）在单线索条件下,老年人返回抑制的出现时间比年轻人晚约200ms,消失的时间比年轻人早约1000ms。（2）在双线索条件下,老年人返回抑制的出现时间比年轻人晚约100ms,消失的时间比年轻人早约500ms。     

语义关联的注意捕获——来自线索化范式的证据

采用线索化范式, 操作性地建立线索和靶子的语义关联, 考察语义关联对注意捕获的影响。实验1采用特征线索意义靶子的形式, 建立某一特定语义水平的注意控制定势, 发现线索靶子语义一致时线索捕获注意, 线索靶子语义不一致时同样的线索失去捕获注意的能力。实验2随机呈现线索颜色和靶子汉字, 建立两种语义概念的注意控制定势, 发现所有的线索都出现了捕获效应, 而不论其在某一具体试次中是否与靶子意义一致。实验3交换了线索与靶子的属性及概念, 采用意义线索特征靶子的形式, 结果与实验1一致。这些结果表明, (1)语义关联的注意捕获符合关联性的无意注意定向假说, 刺激的捕获能力受当前的注意控制定势调节; (2)由语义概念激活的知觉表征在调节空间注意分配上与其自身相比形式相同, 但程度有所下降; (3)知觉特征水平的注意控制定势能够激活与其相应的语义概念, 使其吸引注意并调节空间注意分配; (4)知觉表征和语义概念的激活可能是双向的, 激活后在指导注意转移上表现出相同的特性。     

注意促进运动知觉判断的时间进程

本研究通过控制深度视觉线索, 分析3D SFM (structure from motion)知觉中的眼动特征, 探讨注意对SFM知觉判断的影响及其时间进程。结果显示, 有线索刺激比模糊刺激的判断更加快、更加肯定(百分比更高); 眼睛移动方向和微眼跳方向都分别与知觉判断的运动方向具有一致性; 微眼跳频次、峰速度和幅度也都分别表现出深度线索的促进效应。实验结果表明, SFM知觉过程大致分为速度计算和构建三维结构两个阶段; 注意对SFM知觉的调节作用主要发生在构建三维结构阶段; 注意从150 ms开始指向选择对象, 驻留持续约200 ms后, 从局部运动矢量流转移到整体运动方向的知觉判断。     

线索在多媒体学习中的作用

线索在多媒体学习中作为一种重要的教学设计形式,具有引导注意、组织和整合信息的功能。综述已有研究发现,线索具有引导学习者加工特定位置信息、忽视无关信息干扰的功能;在特定条件下帮助学习者整合图-文信息,并且提高学习者的学习效果;但对于线索信息组织功能尚缺少充分而有力的证据。关于线索对学习效果的影响,大部分研究证实线索能够促进学习。但是由于线索的多样性以及学习材料的复杂性,线索能否有效地提高学习效果仍然存在争议。从认知负荷理论视角综述发现,线索加入并没有明显降低学习者感知到的主观认知负荷;从知觉加工视角而言,线索作为突显的刺激会吸引学习者的注意,从而简化学习者在知觉加工阶段的视觉搜索。未来研究仍然需要关注以下问题:(1)线索是否真的被学习者所注意和加工?(2)重视学习材料多样性比较和不同线索类型差异探讨,(3)关注学习者经验影响,(4)如何在教学设计上保证线索的有效性。     

老龄化对F0轮廓线索在汉语言语识别去掩蔽作用的影响

动态基频(F0)轮廓有助于嘈杂环境下的言语识别,可以作为将目标语音从背景声中分离的知觉线索。本研究通过评估老年人与年轻人在言语掩蔽下聆听具有自然动态F0轮廓与对F0轮廓操作调节后的汉语语句的言语识别能力,探讨老龄化对F0轮廓线索在汉语言语识别去掩蔽作用中的影响。结果显示,在言语掩蔽下自然动态的F0轮廓比压扁或拉伸的F0轮廓更能帮助年轻人抵抗信息掩蔽识别目标言语;而老年人在言语掩蔽下却难以从动态F0轮廓线索中受益。研究结果揭示了老年人利用F0轮廓线索促进掩蔽下言语感知能力的老化特点。     

Developmental trends in utilizing perceptual closure for grouping of shape: effects of spatial proximity and collinearity

In two experiments, visual search was used to study the grouping of shape on the basis of perceptual closure among participants 5-23 years of age. We first showed that young children, like adults, demonstrate an efficient search for a concave target among convex distractors for closed connected stimuli but an inefficient search for open stimuli. Reliable developmental differences, however, were observed in search for fragmented stimuli as a function of spatial proximity and collinearity between the closure-inducing fragments. When only closure was available, search for all the age groups was equally efficient for spatially close fragments and equally inefficient for spatially distant fragments. When closure and collinearity were available, search for spatially close fragments was equally efficient for all the age groups, but search for spatially distant fragments was inefficient for younger children and improved significantly between ages 5 and 10. These findings suggest that young children can utilize closure as efficiently as can adults for the grouping of shape for closed or nearly closed stimuli. When the closure-inducing fragments are spatially distant, only older children and adults, but not 5-year-olds, can utilize collinearity to enhance closure for the perceptual grouping of shape.     

Perceptual grouping in Gabor lattices: proximity and alignment

We propose the Gabor lattice as a new stimulus designed to deal with multiple organizations in perceptual grouping, allowing both comparison between psychophysical data and neural findings and a systematic investigation of grouping based on several low-level characteristics and their interactions. A Gabor lattice is a geometric lattice with Gabor patches, evoking a multistable global orientation percept. Visual grouping in Gabor lattices with elements aligned in a global orientation was compared with grouping of nonaligned Gabor patches and of Gaussian blobs. The effect sizes of proximity and alignment were estimated in logistic regression analyses. The results confirmed the importance of proximity and local element alignment as factors in dynamic grouping. We also found a small but consistent enhancement of grouping along the global vector orthogonal to the local patch orientations. In light of these results, we further motivate the relevance of these stimuli and the associated experimental paradigm.     

Visual training improves perceptual grouping based on basic stimulus features

Training on visual tasks improves performance on basic and higher order visual capacities. Such improvement has been linked to changes in connectivity among mediating neurons. We investigated whether training effects occur for perceptual grouping. It was hypothesized that repeated engagement of integration mechanisms would enhance grouping processes. Thirty-six participants underwent 15 sessions of training on a visual discrimination task that required perceptual grouping. Participants viewed 20?×?20 arrays of dots or Gabor patches and indicated whether the array appeared grouped as vertical or horizontal lines. Across trials stimuli became progressively disorganized, contingent upon successful discrimination. Four visual dimensions were examined, in which grouping was based on similarity in luminance, color, orientation, and motion. Psychophysical thresholds of grouping were assessed before and after training. Results indicate that performance in all four dimensions improved with training. Training on a control condition, which paralleled the discrimination task but without a grouping component, produced no improvement. In addition, training on only the luminance and orientation dimensions improved performance for those conditions as well as for grouping by color, on which training had not occurred. However, improvement from partial training did not generalize to motion. Results demonstrate that a training protocol emphasizing stimulus integration enhanced perceptual grouping. Results suggest that neural mechanisms mediating grouping by common luminance and/or orientation contribute to those mediating grouping by color but do not share resources for grouping by common motion. Results are consistent with theories of perceptual learning emphasizing plasticity in early visual processing regions.     

Age-related decline in prospective memory: the roles of cue accessibility and cue sensitivity.

In two experiments the authors evaluated the hypothesis that age-related decline in prospective memory reflects momentary lapses of intention (MLIs), and explored two factors, cue sensitivity and accessibility, that may contribute to MLIs. MLIs were reliably greater than zero in Experiment 1, indicating that performance fluctuated over the course of the task. Analysis of the response latency data (RL) revealed that older adults demonstrated elevated RL for missed prospective cues and were much slower to respond correctly to prospective cues than younger adults. These findings indicate preserved cue sensitivity in later adulthood and an age-related decline in cue accessibility. Experiment 2 demonstrated that cue sensitivity did not result from an orienting response to the perceptual novelty associated with the prospective cues.     

Configuration-specific attentional modulation of flanker- -target lateral interactions

Elements of a contour are often easier to detect when they possess collinearity, with their local orientations matching the global orientation of the contour. We recently reported attentional modulation of such lateral interactions between a central near-threshold target Gabor patch and flanking high-contrast patches (Freeman et al, 2001 Nature Neuroscience 4 1032-1036). Here, we examined whether such attentional effects reflect specific modulation of mechanisms sensitive to collinear configurations, or instead more general modulation of sensitivity to either the global or local orientation-components of the stimulus. Thresholds for detecting a central Gabor target were measured, while observers also judged the Vernier alignment between one pair of flankers and ignored a second flanker pair (when present). Target contrast-thresholds were facilitated only when attending collinear flankers. There was no facilitation when attending flankers that shared only local orientation with the target, or flankers that fell on a global axis aligned with target orientation but having orthogonal local orientation. Ignored collinear flankers had no effect on target thresholds. These results demonstrate strong and specific attentional modulation of contour-integration mechanisms in early vision sensitive to collinear configurations.     

Age differences in using source-relevant cues.

Subjects heard words originating from 2 speakers and later decided which of the 2 speakers said the words. Older adults had difficulty with source monitoring when perceptual cues from 2 sources were similar (2 female speakers), but this difficulty was overcome when perceptual cues were distinctive (a male and a female speaker) and were the only salient cues to source. Older adults also benefited from distinctive spatial cues when these were the only salient cues to source. Older adults, however, experienced difficulties in using multiple cues (both perceptual and spatial) to source effectively, whereas younger adults were able to use multiple cues to enhance their source-monitoring performance. It is suggested that age differences in source monitoring result from differential cue utilization.     

Reading acquisition enhances an early visual process of contour integration

The acquisition of reading has an extensive impact on the developing brain and leads to enhanced abilities in phonological processing and visual letter perception. Could this expertise also extend to early visual abilities outside the reading domain? Here we studied the performance of illiterate, ex‐illiterate and literate adults closely matched in age, socioeconomic and cultural characteristics, on a contour integration task known to depend on early visual processing. Stimuli consisted of a closed egg‐shaped contour made of disconnected Gabor patches, within a background of randomly oriented Gabor stimuli. Subjects had to decide whether the egg was pointing left or right. Difficulty was varied by jittering the orientation of the Gabor patches forming the contour. Contour integration performance was lower in illiterates than in both ex‐illiterate and literate controls. We argue that this difference in contour perception must reflect a genuine difference in visual function. According to this view, the intensive perceptual training that accompanies reading acquisition also improves early visual abilities, suggesting that the impact of literacy on the visual system is more widespread than originally proposed.     

Age-related differences in emotion matching are limited to low intensity expressions

Multi-label tasks confound age differences in perceptual and cognitive processes. We examined age differences in emotion perception with a technique that did not require verbal labels. Participants matched the emotion expressed by a target to two comparison stimuli, one neutral and one emotional. Angry, disgusted, fearful, happy, and sad facial expressions of varying intensity were used. Although older adults took longer to respond than younger adults, younger adults only outmatched older adults for the lowest intensity disgust and fear expressions. Some participants also completed an identity matching task in which target stimuli were matched on personal identity instead of emotion. Although irrelevant to the judgment, expressed emotion still created interference. All participants were less accurate when the apparent difference in expressive intensity of the matched stimuli was large, suggesting that salient emotion cues increased difficulty of identity matching. Age differences in emotion perception were limited to very low intensity expressions.     

视知觉压力在基本心理能力老化中的作用

信息降格说认为, 感觉功能老化使认知系统难以获得良好的信息输入, 并必须牺牲有限的认知资源获得更好的刺激信息, 使能用于认知加工的资源不足, 造成认知老化。为探讨感觉功能对基本心理能力老化的作用, 该研究采用2(年龄组：年轻、老年组)×4(视知觉压力水平：高、中、低、无噪音)的混合设计, 考察年轻、老年组在相同视知觉压力下基本心理能力的年龄差异。结果发现和无噪音条件相比, 相同视知觉压力下基本心理能力(数字能力、归纳推理能力)的年龄差异减小, 甚至消失, 一定程度上支持信息降格说。视觉功能衰退可能是影响基本心理能力老化的重要因素, 但这种作用受认知资源的调节。     

Combined effects of perceptual grouping cues on object representation: Evidence from motion-induced blindness

We investigated the combined effects of perceptual grouping cues (proximity and contour closure/proximity and orientation similarity) on object representation, using motion-induced blindness, a phenomenon in which salient visual stimuli perceptually disappear when surrounded by moving patterns. We presented as visual targets two stimuli in which a solid square was embedded in an outlined square. Participants reported whether the targets disappeared independently or simultaneously. The results showed that a relatively high proximity cue (with a 0.2-deg separation between the targets) modulated the perceptions of the independent or simultaneous disappearances of targets, regardless of other grouping cues. The contour closure cue modulated these disappearances in the 0.4- to 0.8-deg separations. Finally, the orientation similarity cue began to modulate these disappearances in the 0.6- to 0.8-deg separations. We suggest that the separation between the visual stimuli modulates the combined effects of perceptual grouping cues on complete object representation.