Working memory capacity predicts search accuracy for novel as well as repeated targets

Visual search behaviour is guided by mental representations of targets that direct attention toward relevant features in the environment. Electrophysiological data suggests these target templates are maintained by visual working memory during search for novel targets and rapidly transfer to long term memory with target repetition. If this account is correct, an individual’s working memory capacity should be more predictive of search performance for novel targets than repeated targets. Across six experiments, we tested this hypothesis using both single (Experiments 5 and 6) and multiple (Experiments 1–4) target search tasks with three different types of stimuli (real world objects, letters, and triple conjunction shapes). Each target set was repeated for six consecutive trials. In addition, we estimated visual working memory capacity using a change detection working memory task. Overall, working memory capacity did not predict response time or efficiency in the visual search task. However, working memory capacity was equally predictive of search accuracy for both novel and repeated targets. These results suggest that working memory requirements do not substantially differ between novel and repeated target search, and working memory capacity may continue to play an important role in the encoding or maintenance of target representations after they are presumed to be in long term memory.     

Facilitating memory‐based lie detection in immediate and delayed interviewing: The role of mnemonics

We experimentally investigated how different mnemonic techniques employed in an interview conducted immediately after an event affected truth tellers' and liars' responses when they were interviewed again after a 2‐week delay. We also compared how verbal accounts changed over time within truth tellers and liars, and how consistent both groups were. Participants (n = 143) were shown a mock intelligence operation video and instructed either to tell the truth or lie about its contents in two interviews, one of which was immediately after watching the video and the other after a 2‐week delay. In the immediate interview, they were asked to provide a free recall and then asked to provide further information via one of three mnemonics: context reinstatement, sketch, or event‐line. In the delayed interview, they were asked to provide only a free recall. Truth tellers reported more visual, spatial, temporal, and action details than did liars both immediately and after a delay. Truth tellers experienced more of a decline in reporting details after a delay than did liars, and this decline was affected by the mnemonic used. Truth tellers thus showed, more than liars, patterns of reporting indicative of genuine memory decay. Liars produced patterns of a “stability bias” instead. Truth tellers and liars were equally consistent between their immediate and delayed statements.     

医学生疼痛共情的认知过程特征：来自ERP的证据

以往研究发现临床医生的疼痛共情显著低于常人,表现为前者感知他人疼痛时会出现早期情绪分享和晚期情绪调节的相对抑制。而处于职前培养期的医学生是否存在相似问题,其疼痛共情又是否会受到重复暴露的影响,目前并不清楚。为此,本研究采用ERP技术比较了医学与非医学专业大学生疼痛共情的认知过程,并通过前后测设计检验了重复暴露对二者疼痛共情的影响。行为结果发现两组被试的主观疼痛判断都出现了疼痛共情效应,但未出现组别差异,也未发现重复暴露的影响。但ERP结果显示,医学生的疼痛共情过程显著区别于非医学生。他们虽表现出早期情绪分享成分N1的抑制效应,但LPP反映的晚期认知加工却显著增强,且上述两阶段加工均未受到重复暴露的显著影响。研究表明：（1）医学学习能够抑制疼痛共情的早期情绪分享,但医学生仍可通过更多晚期认知资源投入来维持其疼痛共情水平。（2）医学生的疼痛共情较少受到重复暴露的影响,呈现情绪适应特点。     

Is there a memory profit after repeated learning of subject‐performed actions? Comparing direct and long‐term memory performance level as a function of age

Schatz, T.R., Spranger, T. & Knopf, M. (2010). Is there a memory profit after repeated learning of subject‐performed actions? Comparing direct and long‐term memory performance level as a function of age. Scandinavian Journal of Psychology 51, 465–472. The present two studies investigated the possibility for improvement and maintenance of episodic memory in young and older adults. In a first study, the performance‐enhancing effect of two separate as well as combined learning devices, enactive encoding and repeated learning, was tested. With a time lag of one week, four different series of 30 action phrases were encoded either verbally or by enacting them symbolically. Memory was assessed in four immediate free recall tests. In a second study, the maintenance of the memory profit was tested in an unexpected fifth session half a year later. As expected, there was a steady improvement of memory performance as a function of repeated learning in study one. This holds true regardless of age. In addition, enactive encoding led to a better memory performance than verbal encoding in both age groups. Moreover, younger adults outperformed the elderly regardless of type of encoding. The combination of the two learning devices was not efficient enough to eliminate aging effects in episodic memory. However, memory flexibility is demonstrated also in the elderly. In the long‐term follow‐up, maintenance of learning and memory could be found in all participant groups.     

Children's recall and source monitoring of a repeated event using a timeline as an interview aid

Investigators sometimes use timelines (visual depictions of time) to help children identify temporal information from experienced events or details from a particular instance of a repeated event. However, little is actually known about the efficacy of this visual aid on children's memories. Six‐ to 9‐year‐olds participated in four occurrences of a repeated event and were later interviewed with or without the use of a timeline. Children in the timeline condition were less accurate and made more source‐monitoring errors than those in the control condition. For items that appeared consistently throughout the events, a suggestibility effect was more evident for older children who used the timeline than those who did not. Overall, there was no clear evidence in support of the visual aid. Despite its popularity, our findings suggest that timelines should be further examined to establish whether, and under what circumstances, they might be used in investigative contexts.     

Schema and deviation effects in remembering repeated unfamiliar stories

In today's globalized world, we frequently encounter unfamiliar events that we may have difficulty comprehending – and in turn remembering – due to a lack of appropriate schemata. This research investigated schema effects in a situation where participants established a complex new schema for an unfamiliar type of story through exposure to four variations. We found that immediate recall increased across subsequent stories and that distortions occurred less frequently – participants built on the emerging schema and gradually established representations of parts of the story that were initially transformed. In recall with delays increasing up to 1 month, quantitative measures indicated forgetting while distortions increased. The second focus of this research was on content and order deviation effects on recall. The content deviation, in contrast with previous repeated-event research, was not remembered well and was associated with lower recall; the order deviation had a similar (but expected) effect. We discuss discrepancies between results of this study and previous literature, which had focused on schemata for familiar events, in relation to stages of schema development: it seems that in unfamiliar repeated events, a complex new schema is in the early stages of formation, where the lack of attentional resources limits active processing of deviations.     

Finite Mixtures of Hidden Markov Models for Longitudinal Responses Subject to Drop out

Abstract

Drop out is a typical issue in longitudinal studies. When the missingness is non-ignorable, inference based on the observed data only may be biased. This paper is motivated by the Leiden 85+ study, a longitudinal study conducted to analyze the dynamics of cognitive functioning in the elderly. We account for dependence between longitudinal responses from the same subject using time-varying random effects associated with a heterogeneous hidden Markov chain. As several participants in the study drop out prematurely, we introduce a further random effect model to describe the missing data mechanism. The potential dependence between the random effects in the two equations (and, therefore, between the two processes) is introduced through a joint distribution specified via a latent structure approach. The application of the proposal to data from the Leiden 85+ study shows its effectiveness in modeling heterogeneous longitudinal patterns, possibly influenced by the missing data process. Results from a sensitivity analysis show the robustness of the estimates with respect to misspecification of the missing data mechanism. A simulation study provides evidence for the reliability of the inferential conclusions drawn from the analysis of the Leiden 85+ data.     

The minimal self hypothesis

For millennia self has been conjectured to be necessary for consciousness. But scant empirical evidence has been adduced to support this hypothesis. Inconsistent explications of “self” and failure to design apt experiments have impeded progress. Advocates of phenomenological psychiatry, however, have helped explicate “self,” and employed it to explain some psychopathological symptoms. In those studies, “self” is understood in a minimalist sense, sheer “for-me-ness.” Unfortunately, explication of the “minimal self” (MS) has relied on conceptual analysis, and applications to psychopathology have been hermeneutic, allowing for many degrees of interpretive latitude. The result is that MS’s current scientific status is analogous to that of the “atom,” at the time when “atom” was just beginning to undergo transformation from a philosophical to a scientific concept. Fortunately, there is now an opportunity to promote a similar transformation for “MS.” Discovery of the brain’s Default Mode Network (DMN) opened the door to neuroimaging investigations of self. Taking the DMN and other forms of intrinsic activity as a starting point, an empirical foothold can be established, one that spurs experimental research and that enables extension of research into multiple phenomena. New experimental protocols that posit “MS” can help explain phenomena hitherto not thought to be related to self, thereby hastening development of a mature science of self. In particular, targeting phenomena wherein consciousness is lost and recovered, as in some cases of Unresponsive Wakefulness Syndrome (UWS), allow for design of neuroimaging probes that enable detection of MS during non-conscious states. These probes, as well as other experimental protocols applied to NREM Sleep, General Anesthesia (GA), and the waking state, provide some evidence to suggest that not only can self and consciousness dissociate, MS might be a necessary precondition for conscious experience. Finally, these findings have implications for the science of consciousness: it has been suggested that “levels of consciousness” (LoC) is not a legitimate concept for the science of consciousness. But because we have the conceptual and methodological tools with which to refine investigations of MS, we have the means to identify a possible foundation—a bifurcation point—for consciousness, as well as the means by which to measure degrees of distance from that foundation. These neuroimaging investigations of MS position us to better assess whether LoC has a role to play in a mature science of consciousness.