Prediction and unconscious attention operate synergistically to facilitate stimulus processing: An fMRI study

There is considerable evidence that prediction and attention aid perception. However, little is known about the possible neural mechanisms underlying the impact of prediction and unconscious attention on perception, probably due to the relative neglect of unconscious attention in scholarly literature. Here, we addressed this issue using functional magnetic resonance imaging (fMRI). We adopted a variant of the double-cue paradigm, in which prediction and attention were factorially manipulated by two separate cues (prediction and attention cues). To manipulate consciousness, the attention cues were presented subliminally and supraliminally. Behaviorally, we reported an unconscious-attended effect in the predictable trials and a conscious-attended effect in the unpredictable trials. On the neural level, it was shown that prediction and unconscious attention interacted in the left dorsolateral prefrontal cortex (dlPFC). More specifically, there was a significantly decreased activation in dlPFC for predictable relative to unpredictable stimuli in the unconscious-attended trials, but not in the unconscious-unattended trials. This result suggests that prediction and unconscious attention operate synergistically to facilitate stimulus processing. This is further corroborated by the subsequent functional connectivity analysis, which revealed increased functional connectivity between the left dlPFC and the premotor cortex for predictable versus unpredictable stimuli in the unconscious-attended trials.     

联合Simon效应:现状、影响因素与理论解释

联合Simon效应是一种空间刺激–反应相容性效应,它出现在当两个参与者完成Simon任务的互补成分时。该效应被认为是反映自我–他人整合程度的一个有效指标。影响此现象的因素主要包括社会和非社会因素。社会促进理论、共同表征理论、空间反应编码理论和参照编码理论对该效应作出了解释。未来关于联合Simon效应的研究需深入探讨其影响因素以及脑机制,并进一步完善理论解释。     

Masked suffix priming and morpheme positional constraints

Although masked stem priming (e.g., dealer–DEAL) is one of the most established effects in visual word identification, it is less clear whether primes and targets sharing a suffix (e.g., kindness–WILDNESS) also yield facilitation. In a new take on this issue, we show that prime nonwords facilitate lexical decisions to target words ending with the same suffix (sheeter–TEACHER) compared to a condition where the critical suffix was substituted by another one (sheetal–TEACHER) or by an unrelated nonmorphological ending (sheetub– TEACHER). We also show that this effect is genuinely morphological, as no priming emerged in noncomplex items with the same orthographic characteristics (sportel–BROTHEL vs. sportic–BROTHEL vs. sportur–BROTHEL). In a further experiment, we took advantage of these results to assess whether suffixes are recognized in a position-specific fashion. Masked suffix priming did not emerge when the relative order of stems and suffixes was reversed in the prime nonwords—ersheet did not yield any time saving in the identification of teacher as compared to either alsheet or obsheet. We take these results to show that –er was not identified as a morpheme in ersheet, thus indicating that suffix identification is position specific. This conclusion is in line with data on interference effects in nonword rejection and strongly constrains theoretical proposals on how complex words are identified. In particular, because these findings were reported in a masked priming paradigm, they suggest that positional constraints operate early, most likely at a prelexical level of morpho-orthographic analysis.     

Facial expression coding in children and adolescents with autism: Reduced adaptability but intact norm-based coding

Individuals with autism spectrum disorder (ASD) can have difficulty recognizing emotional expressions. Here, we asked whether the underlying perceptual coding of expression is disrupted. Typical individuals code expression relative to a perceptual (average) norm that is continuously updated by experience. This adaptability of face-coding mechanisms has been linked to performance on various face tasks. We used an adaptation aftereffect paradigm to characterize expression coding in children and adolescents with autism. We asked whether face expression coding is less adaptable in autism and whether there is any fundamental disruption of norm-based coding. If expression coding is norm-based, then the face aftereffects should increase with adaptor expression strength (distance from the average expression). We observed this pattern in both autistic and typically developing participants, suggesting that norm-based coding is fundamentally intact in autism. Critically, however, expression aftereffects were reduced in the autism group, indicating that expression-coding mechanisms are less readily tuned by experience. Reduced adaptability has also been reported for coding of face identity and gaze direction. Thus, there appears to be a pervasive lack of adaptability in face-coding mechanisms in autism, which could contribute to face processing and broader social difficulties in the disorder.     

次要任务对词类判断任务中权力空间表征激活的影响

许多证据表明权力在大脑中是以垂直空间来进行表征的, 具体而言为言语和视觉空间编码。前人研究发现两种编码具有情境依赖性, 即当前任务决定了激活哪种编码。一般的词类判断任务主要依赖于言语编码。然而仍不确定的是, 当排除言语空间编码后, 词类判断任务能否激活视觉空间编码。本研究拟借助双任务范式探讨此问题。实验结果发现单任务条件下出现权力-空间交互, 并且双任务条件下, 这一交互只受到视觉空间次要任务的干扰。这说明, 词类判断任务也可依赖视觉空间编码, 并进一步支持了权力空间表征的情境依赖性。     

Living and Learning: Reproducing Beliefs in Selective Experience

People's decisions shape their experience. For example, a recruitment officer decides between job applicants and cannot evaluate the suitability of rejected applicants. The selection decisions thus affect the content of the officer's experience of suitable and unsuitable applicants, and experiential learning is achieved from a selective sample of experiences. It is suggested that people's beliefs are sensitive to the content of the experienced sample, but the mind cannot adjust for the selectivity of the sample even when it results from the individual's own decisions. Two experiments with a recruitment task showed that incorrect prior beliefs survive experiential learning when the beliefs are reproduced and thus appear to be confirmed, in actual experience. When the task was to achieve high performance, incorrect prior beliefs persisted because they were reproduced in a smaller sample of selected job applicants. In contrast, when the task was focused on learning, a greater number of applicants were selected, and a more representative experience therefore revised incorrect beliefs. The actual content of the experienced sample is thus crucial for the persistence, as well as for the revision, of incorrect beliefs. Further, as predicted by the hypothesis of constructivist coding, when feedback was absent for rejected applicants, participants constructed “internal feedback” in line with the expectation that the rejected applicant was unsuitable. Thus, when fewer applicants were hired, participants came to believe that the actual proportion of suitable applicants was low. Finally, the implications for efforts to reduce bias and improve experiential learning are discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

Visuokinesthetic Realignment in a Video-Controlled Reaching Task

The authors investigated the accuracy of horizontal pointing movements toward a visual target viewed on a vertical video monitor; the view included a directional distortion between perceptual and action spaces. Although accurate coding of the movement vector in a relative (visual) system of coordinates has been found to occur when there is a prismatic perturbation, provided that the hand and the target are continuously visible, such accurate performance has never been reported for video-controlled situations with larger deviations. To evaluate whether visual relative coding is task specific or depends on the magnitude of the induced misalignment, the authors manipulated the intensity of directional perturbation (10° or 40°) in a video-controlled task. Whatever the directional bias, participants (N = 40) were initially inaccurate but adapted quickly within a few trial rehearsals, with a concomitant recalibration of segmental proprioception. In contrast with prism studies, relative coding of the hand-to-target vector seemed not to be operative in video-controlled situations, suggesting that target location is specified in an egocentric system of reference that includes hand-related proprioceptive signals, despite the presence of a (consciously) detected misalignment between visual and kinesthetic systems.     

SNARC效应: 现状、理论与建议

SNARC效应是当对数字进行奇偶判断时,即使数的奇偶性与数的大小无关,但右手（左手）对相对大（小）的数的反应快。首先介绍SNARC效应的起源和理论解释,然后总结SNARC效应的特性,论述SNARC效应和Simon效应以及MARC 效应的关系,并对SNARC效应的脑机制进行了概述,最后提出3个有待深入研究的问题：（1）SNARC效应的加工处理机制;（2）SANRC效应的理论探索;（3）SNARC效应的本质。