Verbal predicates foster conscious recollection but not familiarity of a task-irrelevant perceptual feature – An ERP study

Research on the effects of perceptual manipulations on recognition memory has suggested that (a) recollection is selectively influenced by task-relevant information and (b) familiarity can be considered perceptually specific. The present experiment tested divergent assumptions that (a) perceptual features can influence conscious object recollection via verbal code despite being task-irrelevant and that (b) perceptual features do not influence object familiarity if study is verbal-conceptual. At study, subjects named objects and their presentation colour; this was followed by an old/new object recognition test. Event-related potentials (ERP) showed that a study-test manipulation of colour impacted selectively on the ERP effect associated with recollection, while a size manipulation showed no effect. It is concluded that (a) verbal predicates generated at study are potent episodic memory agents that modulate recollection even if the recovered feature information is task-irrelevant and (b) commonly found perceptual match effects on familiarity critically depend on perceptual processing at study.     

工作记忆中注意焦点转换的代偿机制—— 来自聋生和发音抑制的证据

注意焦点转换是工作记忆中一项重要的执行功能。前人的研究提示视空间画板可能参与言语工作记忆中的注意转换。通过聋生和发音抑制方式探索语音回路子系统受损或受阻后, 视空间画板子系统完成注意转换任务的反应模式。采用“三计数”任务, 实验一比较了极重度耳聋学生和健听学生在工作记忆中的注意焦点转换效应。结果表明聋生与健听被试在不同记忆子项中转换的反应时间均长于不转换时间。但与健听被试相比, 聋生完成注意转换任务的正确率降低, 在转换和不转换之间的反应时差别减小, 且转换方向对反应时无影响, 转换方向和转换距离表现出显著的交互作用。下行转换时近转换快于远转换, 上行转换时近转换慢于远转换。实验二比较了发音抑制和无抑制条件下的注意转换效应, 发音抑制组在注意焦点转换中表现出与聋生组既类似又存在区别的反应模式。这些结果提示工作记忆的中枢执行系统具有高度的灵活性。当语音回路功能受阻后, 注意转换仍能借助视空间画板子系统得以完成。与暂时性抑制相比, 语音回路功能长期受损后表现出一定的功能代偿。     

Thought dismissability in obsessive-compulsive disorder versus panic disorder

This study sought to better understand the persistence of obsessive-compulsive disorder (OCD) by studying the dismissability of obsessional thoughts in individuals with OCD relative to the dismissability of panic-relevant thoughts in individuals with panic disorder with or without agoraphobia (PD/A). Individuals with a principal diagnosis of OCD (n = 25) or PD/A (n = 25) completed a thought replacement task in which they replaced a primary obsession (target thought for the OCD group) or a primary panic-relevant thought (target thought for the PD/A group), with a neutral thought, signaling when the target thought occurred and when the neutral thought was in mind. The OCD group had more target thoughts and appraised the recurrence of the target thought more negatively. Whereas mood state did not change in the PD/A group, it declined in the OCD group, and this change was predicted by negative appraisal of target thought recurrences, but not amount of time thinking the target thought. These findings suggest that in vivo appraisal of the recurrence of obsessions may be a unique, key mechanism in the persistence of OCD and that the identification and exploration of appraisal of thought recurrences may be an especially important target in its treatment.     

Dream rebound of suppressed emotional thoughts: the influence of cognitive load

Initial evidence suggests that suppressing a thought prior to sleep results in subsequent dreaming of that thought. The present research examined the influence of cognitive load on dreaming following suppression. In Experiment 1, 100 participants received either a suppression instruction or no instruction for an intrusive thought prior to sleep, and subsequently completed a dream diary. Participants instructed to suppress reported dreaming about the target thought more than controls; dream rebound was predicted by poorer performance on a working memory task. In Experiment 2, 126 participants received either a suppression instruction or no instruction for an intrusive thought prior to sleep, and half of participants also had cognitive load of learning a 9-digit number. Participants receiving the suppression instruction under cognitive load reported greater dream rebound than other participants. These findings indicate that thought suppression prior to sleep leads to dream rebound, and this effect is enhanced by cognitive load.     

Race-specific perceptual discrimination improvement following short individuation training with faces

This study explores the effect of individuation training on the acquisition of race-specific expertise. First, we investigated whether practice individuating other-race faces yields improvement in perceptual discrimination for novel faces of that race. Second, we asked whether there was similar improvement for novel faces of a different race for which participants received equal practice, but in an orthogonal task that did not require individuation. Caucasian participants were trained to individuate faces of one race (African American or Hispanic) and to make difficult eye-luminance judgments on faces of the other race. By equating these tasks we are able to rule out raw experience, visual attention, or performance/success-induced positivity as the critical factors that produce race-specific improvements. These results indicate that individuation practice is one mechanism through which cognitive, perceptual, and/or social processes promote growth of the own-race face recognition advantage.     

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.     

情绪性记忆的主动遗忘

情绪性记忆的主动遗忘, 是指人们有意识地主动地遗忘带有情绪色彩的记忆内容, 但更多的是那些带来痛苦的负性情绪性记忆。主动遗忘又分为定向遗忘和压抑遗忘, 项目法和字表法是实验室中研究定向遗忘的主要方法, 而白熊任务和TNT任务是研究压抑遗忘的主要范式, 研究者们围绕两种遗忘做了大量研究。未来的研究应更关注情绪性记忆遗忘的不同心理机制, 不同研究范式与心理机制的交互作用, 情绪性记忆遗忘的个体差异, 情绪性记忆遗忘中事件遗忘和情绪反应遗忘的分离等 问题。     

Limitations of perceptual segmentation on contextual cueing in visual search

In visual search, detection of a target in a repeated layout is faster than search within a novel arrangement, demonstrating that contextual invariances can implicitly guide attention to the target location (“contextual cueing”; Chun & Jiang, 1998). Here, we investigated how display segmentation processes influence contextual cueing. Seven experiments showed that grouping by colour and by size can considerably reduce contextual cueing. However, selectively attending to a relevant subgroup of items (that contains the target) preserved context-based learning effects. Finally, the reduction of contextual cueing by means of grouping affected both the latent learning and the recall of display layouts. In sum, all experiments show an influence of grouping on contextual cueing. This influence is larger for variations of spatial (as compared to surface) features and is consistent with the view that learning of contextual relations critically interferes with processes that segment a display into segregated groups of items.     

Active suppression of distractors that match the contents of visual working memory

The biased competition theory proposes that items matching the contents of visual working memory will automatically have an advantage in the competition for attention. However, evidence for an automatic effect has been mixed, perhaps because the memory-driven attentional bias can be overcome by top-down suppression. To test this hypothesis, the Pd component of the event-related potential waveform was used as a marker of attentional suppression. While observers maintained a colour in working memory, task-irrelevant probe arrays were presented that contained an item matching the colour being held in memory. We found that the memory-matching probe elicited a Pd component, indicating that it was being actively suppressed. This result suggests that sensory inputs matching the information being held in visual working memory are automatically detected and generate an “attend-to-me” signal, but this signal can be overridden by an active suppression mechanism to prevent the actual capture of attention.     

Load theory of selective attention and the role of perceptual load: Is it time for revision?

Perceptual load hypothesis is proposed as a compromise between early and late theory of selective attention which states that the selection will operate early when the load on perception is high and it will operate late when the load on perception is low. Experimental findings have shown that the perceptual load hypothesis is too simplistic in nature as perceptual load is not the only determinant of selection processes. It is difficult to apply the load hypothesis to explain the occurrence of early selection in low load displays as well as the selection processes that operate on distractor and target stimuli that are a part of the same object. Factors like spatial proximity, cues that manipulate the spatial extent of attentional focus, salience of targets as well as the distractors, and perceptual grouping between the target and the distractors should be taken into account while explaining the selective control of attention. Thus, the perceptual load of the display is one such factor that affects selective attention and goal-directed behaviour, but it is not the only factor to affect the selective control of attention.