Bimanual reaching across the hemispace: Which hand is yoked to which?

When both hands perform concurrent goal-directed reaches, they become yoked to one another. To investigate the direction of this coupling (i.e., which hand is yoked to which), the temporal dynamics of bimanual reaches were compared with equivalent-amplitude unimanual reaches. These reaches were to target pairs located on either the left or right sides of space; meaning that in the bimanual condition, one hand's contralateral (more difficult) reach accompanied by the other hand's ipsilateral (easier) reach. By comparing which hand's difficult reach was improved more by the presence of the other hand's easier ipsilateral reach, we were able to demonstrate asymmetries in the coupling. When the cost of bimanual reaching was controlled for the contralateral reaching left hand's performance was improved, suggesting that the left hand is yoked to the right during motor output. In contrast, the right hand showed the greatest improvements for contralateral reaching in terms of reaction time, pointing toward a dominant role for the left hand in the processes prior to movement onset. The results may point toward a mechanism for integrating the unitary system of attention with bimanual coordination.     

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.     

注意捕获对注意瞬脱的消弱作用

本研究在经典的注意瞬脱研究范式中变化干扰刺激T2-1或目标刺激T2的颜色特征,探究由新异刺激特征引发的注意捕获对注意瞬脱的影响。结果发现,当改变T2-1或T2的颜色时,这些与任务无关的新异信息可以自下而上地引发注意捕获并减小注意瞬脱。注意瞬脱起因于有限注意资源的分配,资源的分配方式受注意捕获的自动调节。这为解决注意瞬脱到底是有限资源限制还是资源分配提供了新的实证和理论解释。     

注意瞬脱效应的个体差异

注意瞬脱是指个体在对同一位置出现的多个刺激进行识别时, 如果第二个目标刺激出现在第一个目标刺激之后200~500 ms之间, 那么个体对第二个目标刺激的识别会显著降低的现象。研究表明, 注意瞬脱效应在健康人群中存在显著的个体差异, 主要表现在工作记忆、对分心刺激的抑制能力、意向聚焦、情绪状态和人格等方面。近年来, 注意瞬脱的个体差异也在多种神经疾病的临床研究中得到重视。未来的研究应更多关注注意瞬脱效应个体差异背后的神经机制以及应用研究。     

情绪图片的效价与唤醒度在注意瞬脱对抗效应中的作用:来自ERP的证据

以情绪图片为材料,在RSVP任务下检验了效价和唤醒度在注意瞬脱对抗效应中的作用。实验发现效价在对抗注意瞬脱中起主要作用,且正性图片的对抗效应优于负性图片,但唤醒度对注意瞬脱的影响不显著,结果支持积极情绪对抗注意瞬脱的观点。ERP结果进一步发现以上效应发生在P3代表的工作记忆巩固阶段。而在P2和N2代表的早期注意阶段,尽管已出现了注意瞬脱和情绪加工,但二者无显著交互作用。     

Spatial-attention and emotional evocation: line bisection performance and visual art emotional evocation

Lesion studies demonstrate that the right temporal-parietal region (RTP) is important for mediating spatial attention. The RTP is also involved in emotional experiences that can be evoked by art. Normal people vary in their ability to allocate spatial attention, thus, people who can better allocate attention might also be more influenced by the emotional messages of the paintings (evocative impact). Seventeen healthy participants bisected an unlabeled 100mm line and their performance on this task was used to create two groups, individuals who were more (mALB) and less accurate (lALB). These participants also judged 10 paintings on five qualities, Evocative Impact, Aesthetics, Novelty, Technique, and Closure by marking a 100mm line from 1 (low degree) to 10 (high degree). An ANOVA indicated differences in accuracy on the line bisection (LB) between the two groups. Additional ANOVAs, using the quality ratings as the dependent measure, revealed that the mALB group scored the Evocative Impact greater than the lALB group. These results suggest that the differences in attentional bias between the two groups, as indicated by their LB performance, might influence their evocative impact or reactions and also be a 'barometer' of other RTP functions, including emotional processing.     

Intra-individual reaction time variability in schizophrenia, depression and borderline personality disorder

Intra-individual reaction time variability (IIV) in neuropsychological task performance reflects short term fluctuations in performance. Increased IIV has been reported in patients with schizophrenia and could be related to a deficient neural timing mechanism, but the role of IIV in adult patients with other psychiatric disorders has not been established. Therefore, we compared IIV measures obtained in a Go/Nogo task from patients with schizophrenia, major depression and borderline personality disorder. IIV was increased for patients with schizophrenia. When correcting for differences in mean reaction time, depressive and borderline patients also showed increased IIV. Importantly, all groups showed a strong association between IIV and accuracy of task performance. This suggests that increased IIV might be a sensitive marker for the efficiency of top-down attentional control in all diagnostic groups. Aside from these similarities, the complete results including measures of IIV, mean reaction time and accuracy show differential patterns for patients with schizophrenia compared to those with borderline personality disorder or depression. These results are discussed with respect to common versus disorder-specific neural mechanisms underlying increased IIV.     

Disentangling perceptual and motor components in inhibition of return

Following an abrupt onset of a peripheral stimulus (a cue), the response to a visual target is faster when the target appears at the cued position than when it appears at other positions. However, if the stimulus onset asynchrony (SOA) is longer than approximately 300 ms, the response to the target is slower at the cued position than that at other positions. This phenomenon of a longer response time to cued targets is called "inhibition of return" (IOR). Previous hypotheses propose contributions of both response inhibition and attentional inhibition at cued position to IOR, and suggest that responding to the cue can eliminate the component of response inhibition. The current study uses tasks either executing or withholding response to the cue to investigate the relative contributions of response and attention components to IOR. A condition with bilateral display of the cue is also chosen as a control condition, and eight different SOAs between 1,000 and 2,750 ms are tested. Compared to the control condition, response delay to the target at a cued position is eliminated by responding to the cue, and a response advantage to the target at an uncued position is not affected by responding to the cue. Furthermore, both response delay at a cued position and response advantage at an uncued position decrease with SOA in the time window tested in these experiments. The results reported here indicate a dominant response inhibition at a cued position and a primary attentional allocation at an uncued position for IOR. Nonsignificant perceptual/attentional suppression at a cued position is argued to be a benefit for visual detection in a changing world.     

Your divided attention, please! The maintenance of multiple attentional control sets over distinct regions in space

When non-informative peripheral cues precede a target defined by a specific feature, cues that share the critical feature will capture attention while cues that do not will be effectively ignored. We tested whether different attentional control sets can be simultaneously maintained over distinct regions of space. Participants were instructed to respond only to specific colored targets at specific locations. Most trials included non-predictive cues whose location and/or color were either congruent or incongruent with the spatial and/or color properties of the impending target. We observed contingent capture only for cues that were consistent with the attentional control set applied to that region of space. This is the first demonstration that separate attentional control sets can be simultaneously maintained at distinct spatial locations, with implications for the flexibility of endogenous control over automatic attentional orienting.     

The attention cascade model and attentional blink

An attention cascade model is proposed to account for attentional blinks in rapid serial visual presentation (RSVP) of stimuli. Data were collected using single characters in a single RSVP stream at 10Hz [Shih, S., & Reeves, A. (2007). Attentional capture in rapid serial visual presentation. Spatial Vision, 20(4), 301-315], and single words, in both single and dual RSVP streams at 19Hz [Potter, M. C., Staub, A., & O'Connor, D. H. (2002). The time course of competition for attention: Attention is initially labile. Journal of Experimental Psychology: Human Perception and Performance, 28(5), 1149-1162]. The model adopts similar architecture of the cognitive accounts of attentional blinks and employs computational details from theories of attention gating. The model has elaborated working memory and attention control mechanism. Both bottom-up and top-down salience are explicit in the model. Quantitative fits are good and the model parameters have plausible values. The model handles stimulus competition, lag 1 sparing, intrusion errors, and magnitude of the dip; it also accounts for commonly observed effects such as stimulus similarities (local and global), target+1 blank, and stimulus salience.