客体工作记忆任务中大脑皮层活动的记忆负荷效应

利用128导事件相关电位技术,采用延迟匹配任务的实验范式,测查了20名正常被试完成不同负荷客体任务时的皮层慢电位（slow cortical potentials,简称sp成分）,实验发现：背侧前额叶在刺激呈现后的700ms到1400ms出现记忆负荷效应,高负荷任务诱发的sp成分显著负于低负荷任务;低负荷任务诱发的sp成分在左前额区（500~1800ms）、左前额-中央区（700~1800ms）、左中央-顶叶区（1000~1400s和1800~4800ms）、右前额区（1800~4800ms）和右前额-中央区（1400~4800ms）显著负于高负荷任务,出现记忆负荷效应,但这种负荷效应在左右大脑半球所反映的心理意义可能不同     

The effects of task-irrelevant threatening stimuli on orienting- and executive attentional processes under cognitive load

Human visual attention is biased to rapidly detect threats in the environment so that our nervous system can initiate quick reactions. The processes underlying threat detection (and how they operate under cognitive load), however, are still poorly understood. Thus, we sought to test the impact of task-irrelevant threatening stimuli on the salience network and executive control of attention during low and high cognitive load. Participants were exposed to neutral or threatening pictures (with moderate and high arousal levels) as task-irrelevant distractors in near (parafoveal) and far (peripheral) positions while searching for numbers in ascending order in a matrix array. We measured reaction times and recorded eye-movements. Our results showed that task-irrelevant distractors primarily influenced behavioural measures during high cognitive load. The distracting effect of threatening images with moderate arousal level slowed reaction times for finding the first number. However, this slowing was offset by high arousal threatening stimuli, leading to overall shorter search times. Eye-tracking measures showed that participants fixated threatening pictures more later and for shorter durations compared to neutral images. Together, our results indicate a complex relationship between threats and attention that results not in a unitary bias but in a sequence of effects that unfold over time.     

Le voisinage orthographique influence la catégorisation de couleur des mots différemment selon l’âge et la vitesse de traitement

The objective of this research was to determine to what extent the effect of higher-frequency orthographic neighbourhood in a word colour-categorization task is changed during aging when processing speed is taken into account. In addition, the effect of the lexicality of the stimuli on colour categorization was examined, as well as its variation according to age and processing speed. Fifty-two young adults (M_age = 21.62) and 52 older adults (M_age = 66.04) participated in this study. For each age group, two sub-groups were created according to the processing speed of the participants as measured by the WAIS Coding subtest. Two conditions of words (written in red, yellow, green or blue) were presented in a colour-categorization task. Half of the words did not have any orthographic neighbours (e.g., pistil [pistil]), while the other half had a higher-frequency neighbour (e.g., tirade [tirade]/TIRAGE [draw]). A control condition with a series of Xs was added to test the influence of the effect of the lexicality of words on the colour-categorization times. As a whole, the results showed slower colour-categorization times for words compared to a series of Xs, which did not vary with age and processing speed. Importantly, the results showed that orthographic neighbourhood frequency interacted with age and processing speed, on colour categorization response times. More precisely, the neighbourhood frequency effect was found to vary differently according to processing speed in each age group. For the fastest young adults, the facilitatory effect of higher-frequency orthographic neighbourhood was obtained, whereas no such effect was found for the slowest young adults. The fastest older adults did not exhibit any effect of higher-frequency orthographic neighbourhood whereas a facilitatory effect was observed for the slowest older adults. Therefore, these data suggest that both aging and the processing speed of the participants influence the interference effect of reading on colour categorization. These findings are discussed in the context of cognitive aging theories and models of written word recognition.     

Temperamental contributions to children's performance in an emotion-word processing task: a behavioral and electrophysiological study

Seven-year-old children (N=65) participating in a study of the influence of infant temperament on socioemotional development performed an auditory selective attention task involving words that varied in both affective (positive vs. negative) and social (social vs. nonsocial) content. Parent report of contemporaneous child temperament was also collected, and individual differences in self-regulation in the affective (soothability) and cognitive (attentional control) domains were noted. Overall, children showed slower responses to stimuli that were either social or negative in content, with the largest effect elicited by words that possessed both traits. Children rated high in soothability and attentional control showed slower responses to social negative words. The other children showed little to no differential response patterns across the word categories. ERPs collected during the task indicated that processing differences were evident in the later more cognitive components of the ERP, especially in children low in attentional control. These findings indicate that performance on an auditory selective attention task can assist in identifying underlying patterns of affective processing.     

The role of perceptual load in inattentional blindness

Perceptual load theory offers a resolution to the long-standing early vs. late selection debate over whether task-irrelevant stimuli are perceived, suggesting that irrelevant perception depends upon the perceptual load of task-relevant processing. However, previous evidence for this theory has relied on RTs and neuroimaging. Here we tested the effects of load on conscious perception using the "inattentional blindness" paradigm. As predicted by load theory, awareness of a task-irrelevant stimulus was significantly reduced by higher perceptual load (with increased numbers of search items, or a harder discrimination vs. detection task). These results demonstrate that conscious perception of task-irrelevant stimuli critically depends upon the level of task-relevant perceptual load rather than intentions or expectations, thus enhancing the resolution to the early vs. late selection debate offered by the perceptual load theory.     

IAT范式下自尊内隐性的再证明

该研究用IAT测量了被试的内隐自尊,并通过操纵被试在不同的认知负荷条件下进行外显自我评价来考察外显自我评价和内隐自尊之间的关系。得到的结论是,在低认知负荷条件下进行外显自我评价时,外显自我评价和内隐自尊没有表现出一致性;在高认知负荷条件下进行外显自我评价时,外显自我评价和内隐自尊表现出一致性。该研究在IAT范式下表明了内隐自尊和外显自尊的分离,内隐自尊具有无意识性和自动化的特点。     

Failure to warn: How student race affects warnings of potential academic difficulty

In two studies, we document “failure to warn”—a reduced likelihood of warning Black students against potential academic difficulty compared to White students. In both studies, participants placed in the role of academic advisors saw a highly challenging academic course plan, attributed to either a Black or a White student, and gave Black students less warning about the potential negative consequences of taking on the proposed plan. Study 1 (N = 172) demonstrates this effect using undergraduate peer academic advisors, and Study 2 (N = 58) provides evidence that this effect is moderated by Internal Motivation to Respond Without Prejudice (Plant & Devine, 1998), suggesting that this effect is driven by the fear that discouraging an ambitious Black student might reflect prejudice. This well-intentioned concern can have the ironic consequence of leading the recipients of this advice into academic difficulties.     

Neural correlates of variable working memory load across adult age and skill: dissociative patterns within the fronto-parietal network

We examined neural changes related to variations in working memory load by using an n -back task with three levels and functional magnetic resonance imaging. Younger adults were divided into high- and low-performing groups (Young-High; Young-Low) and compared with older adults. Relative to Young-High, capacity-constraints in working memory were apparent between load 1–2 for the elderly and between load 2–3 for Young-Low. Capacity-constraints in neural activity followed this pattern by showing a monotonically increasing response in parietal cortex and thalamus for Young-High, whereas activity leveled off at 1-back for the elderly and at 2-back for Young-Low. The response in dorsal frontal cortex followed a similar pattern with the addition that the magnitude of activation differed within capacity limitations (Old > Young at 1-back; Young-Low > Young-High at 2-back). These findings indicate that an important determinant of WM capacity is the ability to keep the frontal cortex adequately engaged in relation to current task demands.