情绪效价与面孔类型对幼儿无意视盲的影响

幼儿对不同的情绪面孔图片存在不同的注意偏向,考察情绪效价与面孔类型对幼儿无意视盲的影响,可以帮助我们进一步认识幼儿对情绪面孔的注意偏向。本研究采用静态无意视盲的实验范式,通过2（面孔类型：符号化卡通、真人）×2（情绪效价：积极、消极）被试间完全随机设计,考察了111名幼儿（62.5±3.6个月,男生60名）在无意注意条件下对不同情绪效价和不同类型面孔的觉察情况。结果表明：（1）幼儿对积极情绪面孔的觉察率显著高于消极情绪面孔;（2）符号化卡通面孔与真人面孔的整体觉察率不存在显著差异;（3）积极情绪面孔中符号化卡通面孔的觉察率高于真人面孔。综上,情绪效价对无意视盲的影响会基于面孔类型的不同而不同,幼儿对卡通积极情绪面孔有更显著的注意偏向。     

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。     

Infants' reasoning about opaque and transparent occluders in an individuation task

Two experiments document that conceptual knowledge influences 3-year-olds' extension of novel words. In Experiment 1, when objects were described as having conceptual properties typical of artifacts, children extended novel labels for these objects on the basis of shape alone. When the very same objects were described as having conceptual properties typical of animate kinds, children extended novel labels for these objects on the basis of both shape and texture. Moreover, providing a salient perceptual cue (Experiment 2) did not interfere with children's reliance on conceptual information in extending novel words: when an object with eyes was labeled with a novel word in the context of a story describing the object as an artifact, children extended the label on the basis of shape alone (i.e. as though the object were an artifact). These results, which challenge directly the position that 'dumb attentional mechanisms' can account for word learning, stand as evidence for the central role of conceptual information in mapping words to meaning.     

Detection of a change in photorealism1

The perceived degree of photorealism is interpreted as reflecting the artificialness or naturalness of images. Natural images (real‐scene photographs) are images with high degrees of naturalness, while artificial images (e.g., paintings) are images with low degrees of naturalness. Alternatively, natural images are images with low degrees of artificialness, while artificial images are images with high degrees of artificialness. We attempted to disambiguate these two interpretations of the perception of photorealism by using a change‐blindness paradigm. Participants observed an image sequence showing a gradual transformation from a natural image to an artificial image or vice versa, and reported changes they noticed. More participants reported noticing changes in photorealism for the natural‐to‐artificial transformations than for the opposite transformations. This asymmetry indicates that disappearing naturalness was detected more readily than emerging naturalness, or alternatively, emerging artificialness was detected more readily than disappearing artificialness. The results for the control conditions showed that the emergence of visual information was detected more readily than the disappearance. These results suggest that the perception of photorealism should be considered as the perception of artificialness.     

先天视觉经验缺失对颜色认知的影响：一项ERP研究

感觉与认知是否是相互独立的？本研究通过对比先天盲被试与明眼被试在进行物体颜色判断时的行为反应和神经电生理信号变化,探讨视觉经验缺失对颜色认知的影响。结果发现,先天盲被试具有一定的颜色知识,但其水平低于明眼被试;两组被试都出现了由颜色不匹配所诱发的N400效应,且都表现出左半球优势;但是盲人组的N400效应大于明眼组,盲人组的N400反应潜伏期小于明眼组。该结果说明,直接的视觉经验是颜色认知的充分条件而非必要条件。     

Affective stimuli capture attention regardless of categorical distinctiveness: An emotion-induced blindness study

Affective stimuli capture attention, whether their affective value stems from emotional content or a history of reward. The uniqueness of such stimuli within their experimental contexts might imbue them with an enhanced categorical distinctiveness that accounts for their impact on attention. Indeed, in emotion-induced blindness, categorically distinctive neutral pictures disrupt target perception, albeit to a lesser degree than do emotional pictures. Here, we manipulated the categorical distinctiveness of distractors in an emotion-induced blindness task. Participants searched within RSVP streams for a target that followed an emotional or a neutral distractor picture. In a categorically homogenous condition, all non-distractor items were exemplars from a uniform category, thus enhancing the distractor's categorical distinctiveness. In a categorically heterogeneous condition, each non-distractor item represented a distinct category. Neutral distractors disrupted target perception only in the homogenous condition, but emotional distractors did so regardless of their categorical distinctiveness.     

The cost of seeing the meaning: Conceptual processing of distractors triggers localized target suppression

It is often assumed that conceptual information impacts visual experience only after perceptual information has been extracted. However, the present study suggests that conceptual processing can interfere with perceptual processes, as reflected in target perception impairments that are specific to the location of conceptually salient distractors. Experiment 1 replicated previous findings that emotional distractors in a rapid serial visual presentation cause a spontaneous, spatially localized impairment in target perception, further finding that distractors that are merely featurally salient do not. Experiment 2 suggested that conceptually salient distractors that are non-emotional also elicit such spatially localized impairments, which are shorter lived than those following emotional distractors. Experiment 3 suggested that featurally salient distractors that are not conceptually salient engage a different, spatial attention mechanism. Together, these findings suggest that, whereas featurally salient distractors can capture spatial attention, conceptual distractors additionally engage mechanisms that suppress spatiotemporally competing targets.     

Manipulations of distractor frequency do not mitigate emotion-induced blindness

Emotional distractors can impair perception of subsequently presented targets, a phenomenon called emotion-induced blindness. Do emotional distractors lose their power to disrupt perception when appearing with increased frequency, perhaps due to desensitisation or enhanced recruitment of proactive control? Non-emotional tasks, such as the Stroop, have revealed that high frequency distractors or conflict lead to reduced interference, and distractor frequency appears to modulate attentional capture by emotional distractors in spatial attention tasks. But emotion-induced blindness is thought to reflect perceptual competition between targets and emotional distractors, and it is unclear whether high frequency emotional stimuli cause less disruption at this relatively early stage of processing. In four experiments, participants searched streams of images for a rotated target image. A negative or neutral distractor appeared before the target, and their relative frequency was manipulated. Across all experiments, the frequency of emotional distractors did not modulate emotion-induced blindness even when participants were explicitly informed that they would appear often or seldom. Thus, increased distractor frequency does not appear to mitigate the priority allotted to emotional distractors during perceptual competition.     

The Occipital Cortex in the Blind

ABSTRACT— Studying the brains of blind individuals provides a unique opportunity to investigate how the brain changes and adapts in response to afferent (input) and efferent (output) demands. We discuss evidence suggesting that regions of the brain normally associated with the processing of visual information undergo remarkable dynamic change in response to blindness. These neuroplastic changes implicate not only processing carried out by the remaining senses but also higher cognitive functions such as language and memory. A strong emphasis is placed on evidence obtained from advanced neuroimaging techniques that allow researchers to identify areas of human brain activity, as well as from lesion approaches (both reversible and irreversible) to address the functional relevance and role of these activated areas. A possible mechanism and conceptual framework for these physiological and behavioral changes is proposed.