Measuring consciousness: Is one measure better than the other?

What is the best way of assessing the extent to which people are aware of a stimulus? Here, using a masked visual identification task, we compared three measures of subjective awareness: The Perceptual Awareness Scale (PAS), through which participants are asked to rate the clarity of their visual experience; confidence ratings (CR), through which participants express their confidence in their identification decisions, and Post-decision wagering (PDW), in which participants place a monetary wager on their decisions. We conducted detailed explorations of the relationships between awareness and identification performance, looking to determine (1) which scale best correlates with performance, and (2) whether we can detect performance in the absence of awareness and how the scales differ from each other in terms of revealing such unconscious processing. Based on these findings we discuss whether perceptual awareness should be considered graded or dichotomous. Results showed that PAS showed a much stronger performance-awareness correlation than either CR or PDW, particularly for low stimulus intensities. In general, all scales indicated above-chance performance when participants claimed not to have seen anything. However, such above-chance performance only showed when we also observed a correlation between awareness and performance. Thus (1) PAS seems to be the most exhaustive measure of awareness, and (2) we find support for above-chance performance in the absence of subjective awareness, but such unconscious knowledge only contributes to performance when we observe conscious knowledge as well. Similarities and differences between scales are discussed in the light of consciousness theories and response strategies.     

Partial awareness distinguishes between measuring conscious perception and conscious content: Reply to Dienes and Seth

In their comment on Sandberg, Timmermans, Overgaard, and Cleeremans (2010), Dienes and Seth argue that increased sensitivity of the Perceptual Awareness Scale (PAS) is a consequence of the scale being less exclusive rather than more exhaustive. According to Dienes and Seth, this is because PAS may measure some conscious content, though not necessarily relevant conscious content, “If one saw a square but was only aware of seeing a flash of something, then one has not consciously seen a square.” In this reply, we claim that there is a difference between conscious visual experience, which may be partial, and the resulting conscious content, which is conceptual. Whereas PAS measures the first, confidence judgments and post-decision wagering measure the second.     

Subjective discriminability of invisibility: A framework for distinguishing perceptual and attentional failures of awareness

Conscious visual perception can fail in many circumstances. However, little is known about the causes and processes leading to failures of visual awareness. In this study, we introduce a new signal detection measure termed subjective discriminability of invisibility (SDI) that allows one to distinguish between subjective blindness due to reduction of sensory signals or to lack of attentional access to sensory signals. The SDI is computed based upon subjective confidence in reporting the absence of a target (i.e., miss and correct rejection trials). Using this new measure, we found that target misses were subjectively indistinguishable from physical absence when contrast reduction, backward masking and flash suppression were used, whereas confidence was appropriately modulated when dual task, attentional blink and spatial uncertainty methods were employed. These results show that failure of visual perception can be identified as either a result of perceptual or attentional blindness depending on the circumstances under which visual awareness was impaired.     

错误正波的神经发生源与功能意义解释

错误正波(error positivity, Pe)是指在错误反应后200~600ms后出现的事件相关电位(ERP)的正偏转, 对Pe的研究有助于揭示人类错误加工机制的全貌。现有研究表明Pe主要产生于前扣带回喙部, 但不同的研究对其精细神经发生源并没有达成一致。Pe的功能意义解释主要有错误意识假说、行为适应假说、情绪评估假说。当根据有关P3的理论来解释Pe的功能意义时, Pe可能反映了对错误背景的刷新。然而上述每一种对Pe的功能意义的解释都还受到了一些研究结果的质疑和挑战。基于此, 作者对现有研究存在的问题进行了总结和分析, 并对今后如何对Pe的神经发生源和功能意义的进一步研究提出了建议。     

情绪智力的基础：情绪觉察的研究现状与展望

情绪觉察作为情绪智力的重要基础,指的是识别与描述自己和他人情绪的能力,对个体的心理健康,人际交往具有重要意义。为系统考察情绪觉察的研究现状,采用定性和定量相结合的方式回顾以往研究,即先采用文献计量学的方法定量分析该领域研究的概况,然后在此基础上,对研究的具体内容从概念界定、测量工具、神经基础、相关因素和干预研究五个方面作进一步系统梳理。最后,对以往研究进行了总结和展望,以期为今后研究提供借鉴。     

4~7岁儿童汉字正字法意识的发展

本研究采用两项实验考察学龄前儿童正字法意识的发展情况。实验1选取146名4~7岁儿童被试,要求其在计算机上完成词汇判断任务,刺激材料分为部件错误非字,部件位置错误非字,假字和真字。结果显示：大班在两项非字条件上的正确率均显著高于假字,而小班各条件差异均不显著;中班在部件位置错误非字上的正确率显著高于假字。表明学龄前儿童的正字法意识已经开始逐渐发展,且部件位置意识比部件意识容易获得。实验2采用Tobii T120型眼动仪,记录24名大班儿童在词汇判断（同实验1）过程中对刺激项目关注的眼动行为,从实时加工的过程探讨学龄前儿童正字法意识的发展。结果显示：儿童对部件错误非字/部件位置错误非字的目标部件的晚期关注程度显著高于假字,有力地证明：学龄前大班儿童已经具有部件和部件位置的意识。     

声符和义符在形声字语音、语义提取中的作用

采用眼动技术记录汉语阅读者在形声字的语音、语义提取中对声符和义符的注意规律, 考察形声字部件的位置、功能和正字法意识对汉字认知的影响。结果表明：(1)在汉字的视觉加工中, 阅读者对部件空间位置的注意加工优势受到声旁位置的调节。对左形右声结构的汉字, 被试更多地注意字的右边, 对右形左声结构的汉字, 被试更多地注意字的左边; (2)在汉语阅读者的正字法规则中, 存在着“左侧释义、右侧释音”的部件的位置-功能联结。(3)在通达形声字的语音、语义的过程中, 与义符相比, 声符具有注意资源的优势, 这种优势在语音提取任务中更加明显：声符无需依赖义符的信息便可以相对独立地激活整字的语音, 但声符需要义符的配合才能够提取整字的语义。     

3-6岁儿童汉字字形认知的发展

以汉字、一般线条图、似字线条图和笔画组合为材料,采用字典判断任务考察3-6岁儿童汉字字形认知的发展特点。结果发现儿童辨别汉字与似字符号的能力随年龄增长显著提高。3岁儿童较难区分汉字与各类似字符号。4-5岁儿童对汉字笔画特征有了一定意识。6岁儿童对汉字组合模式的认识显著提高。笔画意识出现较早且发展速度较快,组合模式意识出现较晚且发展速度较慢。5岁和6岁是汉字字形认知发展的重要时期。     

3-5岁儿童汉字方向敏感性的发展

通过Surface Pro触屏电脑呈现知觉匹配任务,记录儿童的主动反应,探查了83名3-5岁学前儿童汉字方向（倒置与镜像）敏感性的早期发展及其与汉字阅读能力的关系。结果发现,4岁儿童可以很好地区分正反方向的汉字,表现出汉字倒置方向的敏感性。但是,各年龄组儿童还未对镜像汉字表现出敏感性。学前儿童对汉字两种方向的认识表现出不同的发展轨迹。学前儿童的汉字倒置方向敏感性与其汉字阅读能力显著相关。     

Perceptual biases in processing facial identity and emotion

Normal observers demonstrate a bias to process the left sides of faces during perceptual judgments about identity or emotion. This effect suggests a right cerebral hemisphere processing bias. To test the role of the right hemisphere and the involvement of configural processing underlying this effect, young and older control observers and patients with right hemisphere damage completed two chimeric faces tasks (emotion judgment and face identity matching) with both upright and inverted faces. For control observers, the emotion judgment task elicited a strong left-sided perceptual bias that was reduced in young controls and eliminated in older controls by face inversion. Right hemisphere damage reversed the bias, suggesting the right hemisphere was dominant for this task, but that the left hemisphere could be flexibly recruited when right hemisphere mechanisms are not available or dominant. In contrast, face identity judgments were associated most clearly with a vertical bias favouring the uppermost stimuli that was eliminated by face inversion and right hemisphere lesions. The results suggest these tasks involve different neurocognitive mechanisms. The role of the right hemisphere and ventral cortical stream involvement with configural processes in face processing is discussed.