The importance of differentiation in young children’s acquisition of expertise

In a short-term longitudinal study, stories told about novel creatures conveyed information varying in its capability for differentiating. Depending on the context, a bodily feature could be functionally undifferentiated (FUF), meaning that its subtypes (e.g., eyes of two forms) shared a generic function (“seeing”), or functionally differentiated (FDF), meaning that each subtype’s function was unique to it (e.g., only a “hooded eye” could “see in a sandstorm”). 5- to 6-year-olds who heard 8 stories, but not those who heard only 4, cited FDFs more than FUFs in a pair-justification test of judged similarity; and their delayed recall of specific story events was greater when FDFs rather than FUFs were involved. In the absence of direct instruction, young children show sensitivity to the degree of differentiation afforded by feature-function relations.     

Memory for Music in Alzheimer’s Disease: Unforgettable?

The notion that memory for music can be preserved in patients with Alzheimer’s Disease (AD) has been raised by a number of case studies. In this paper, we review the current research examining musical memory in patients with AD. In keeping with models of memory described in the non-musical domain, we propose that various forms of musical memory exist, and may be differentially impaired in AD, reflecting the pattern of neuropathological changes associated with the condition. Our synthesis of this literature reveals a dissociation between explicit and implicit musical memory functions. Implicit, specifically procedural musical memory, or the ability to play a musical instrument, can be spared in musicians with AD. In contrast, explicit musical memory, or the recognition of familiar or unfamiliar melodies, is typically impaired. Thus, the notion that music is unforgettable in AD is not wholly supported. Rather, it appears that the ability to play a musical instrument may be unforgettable in some musicians with AD.     

Aerobic Exercise Enhances Cognitive Flexibility

Introduction Physical activity is believed to prevent cognitive decline and may enhance frontal lobe activity. Methods Subjects were 91 healthy adults enrolled in a wellness center. Over a 10 week intervention, controls were aerobically active 0–2 days per week. Half the intervention group was active 3–4 days/week and half 5–7 days/week. Outcome measures included memory, mental speed, reaction time, attention, and cognitive flexibility. Results Neurocognitive data were analyzed by repeated measures comparing minimal aerobic exercise (the control group) to moderate aerobic exercise (3–4 days/week), and to high aerobic exercise (5–7 days/week). Initial analyses noted significant improvements in mental speed (p = .03), attention (p = .047), and cognitive flexibility (p = .002). After controlling for age, gender, education, and changes in psychomotor speed, only cognitive flexibility still showed significant improvements (p = .02). Conclusion Over a 10 week period, increasing frequency of aerobic activity was shown to be associated with enhanced cognitive performance, in particular cognitive flexibility, a measure of executive function.     

Metamemory in tufted capuchin monkeys (Cebus apella)

Whereas evidence for metacognition by nonhuman primates has been obtained in great apes and old world monkeys, it is weaker in new world monkeys. For instance, capuchin monkeys may fail to recognize their own knowledge of the location of invisible bait. In the present study, we tested whether tufted capuchin monkeys would flexibly change their behavior in a delayed matching-to-sample (DMTS) test depending upon the strength of their memory trace of the sample. In Experiment 1, two monkeys were tested on a modified 9-alternative DMTS task with various delays on a computerized display. In some trials, the monkeys could choose whether to go for a memory test or for a simple key touch as an escape from the test. In other trials, they were forced to go for the memory test. Both monkeys escaped from the memory test more often when their matching accuracy on forced tests was lower. In one of the monkeys, the matching accuracies on chosen memory tests decreased more slowly as a function of delay length, and were higher after long delays than those on forced memory tests. This suggests that at least one capuchin monkey was able to recognize the strength of his own memory trace. Experiment 2 employed occasional no-sample tests, in which the monkeys faced the task choice without presentation of any sample for the trial. The monkey who was successful in Experiment 1 declined the memory test more often in no-sample trials than regular trials, further indicating metamemory in this individual. In Experiment 3, this successful monkey received a task, in which he was sometimes able to choose between shape MTS or texture MTS tasks. However, his matching accuracies did not differ between chosen tasks and forced tasks. Thus, the metamemory possessed by this new world monkey species may be more like a flag, showing strength of memory trace, than an elaborate representation showing details of the memory trace.     

Object permanence in lemurs

Object permanence, the ability to mentally represent objects that have disappeared from view, should be advantageous to animals in their interaction with the natural world. The objective of this study was to examine whether lemurs possess object permanence. Thirteen adult subjects representing four species of diurnal lemur (Eulemur fulvus rufus, Eulemur mongoz, Lemur catta and Hapalemur griseus) were presented with seven standard Piagetian visible and invisible object displacement tests, plus one single visible test where the subject had to wait predetermined times before allowed to search, and two invisible tests where each hiding place was made visually unique. In all visible tests lemurs were able to find an object that had been in clear view before being hidden. However, when lemurs were not allowed to search for up to 25-s, performance declined with increasing time-delay. Subjects did not outperform chance on any invisible displacements regardless of whether hiding places were visually uniform or unique, therefore the upper limit of object permanence observed was Stage 5b. Lemur species in this study eat stationary foods and are not subject to stalking predators, thus Stage 5 object permanence is probably sufficient to solve most problems encountered in the wild.     

归纳推理多样性效应的发展及其争论

归纳推理多样性效应指的是在归纳论断中,前提项目数量越多、越多样,将能构成归纳力度越强的推理。已有研究表明成人的归纳推理明显受到前提项目多样性的影响,而幼儿的相关研究却存在着两种对立的观点：一是认为幼儿不能基于多样性进行推理,二是认为5岁左右的幼儿就能够基于多样性进行推理。出现此争论的原因可能与研究方法方面的差异有关,如实验范式与前提组间差异、实验材料类别与概念范畴、属性特征及呈现方式、推理形式;此外,儿童的知识经验也是一个影响因素。未来研究可以结合相关领域的研究范式;深入挖掘影响儿童表现出多样性效应的因素;将任务设计多样化;将实验任务的计分方式多样化;开展相关的应用研究。     

Confidence in Dyadic Decision Making: The Role of Individual Differences

Groups typically express more confidence than individuals, yet how individual‐level confidence combines during collaborative decision tasks is not well understood. We prescreened 686 community members using a novel confidence measure (a true/false trivia test) intentionally designed to be difficult (accuracy rates were not significantly better than chance) and randomly assigned 72 individuals to collaborate on a matched version of the same test in dyads composed of two low‐confidence individuals, two high‐confidence individuals, or one of each (“mixed”). Consistent with past research, we found that the confidence expressed by dyads was higher than the confidence expressed by individuals; importantly, however, this pattern varied markedly by dyad type, with low‐confidence dyads showing the largest increase, mixed dyads showing a moderate increase, and high‐confidence dyads showing no increase—despite the fact that all dyads showed similarly low accuracy (about 55%). These results highlight the conditions under which groups express greater confidence than individuals and offer insights for the composition of collaborative decision‐making teams. Copyright © 2015 John Wiley & Sons, Ltd.     

Confidently Biased: Comparisons with Anchors Bias Estimates and Increase Confidence

Across a wide variety of situations, exposure to anchors has been shown to bias people's estimates. What is not known, however, is whether externally provided anchors influence the confidence that people have in their estimates. Our studies had two goals. First, we tested whether exposure to anchors influenced people's subjective confidence levels (Studies 1 and 2). These studies revealed that people who made estimates after making comparisons with externally provided anchors tended to be more confident in their estimates than people who did not see anchors. The second goal was to test two explanations as to why anchors increase people's confidence. In Study 3, we tested the explanation that anchors increase confidence because participants thought the anchors provided useful information. In Study 4, we tested the explanation that exposure to anchors causes people to consider a narrower range of plausible values as compared to when not exposed to anchors. Support was found only for the explanation that comparisons with anchors increase confidence because people who are exposed to anchors consider a narrower range of plausible values. Taken together, these studies reveal the powerful influence anchors can have—they not only bias estimates, but also increase people's confidence in their biased estimates. Copyright © 2016 John Wiley & Sons, Ltd.     

Probabilities Associated with Precise and Vague Forecasts

Forecasts of future outcomes, such as the consequences of climate change, are given with different degrees of precision. Logically, more precise forecasts (e.g., a temperature increase of 3–4°) have a smaller probability of capturing the actual outcome than less precise forecasts (e.g., a temperature increase of 2–6°). Nevertheless, people often trust precise forecasts more than vague forecasts, perhaps because precision is associated with knowledge and expertise. In five experiments, we ask whether people expect highly confident forecasts to be associated with wider or narrower outcome ranges than less confident forecasts (Experiments 1, 2, and 5), and, conversely, whether they expect precise forecasts to be issued with higher or lower confidence than vague forecasts (Experiments 3 and 4). The results revealed two distinct ways of thinking about confidence intervals, labeled distributional (wide intervals seen as more probable than narrow intervals) and associative (wide intervals seen as more uncertain than narrow intervals). Distributional responses occurred somewhat more often in within‐subjects designs, where wide and narrow prediction intervals and high and low probability estimates can be directly compared, whereas separate evaluations (in between‐subjects design) suggested associative responses to be slightly more frequent. These findings are relevant for experts communicating forecasts through confidence intervals. Copyright © 2017 John Wiley & Sons, Ltd.     

决策信心在信息化从众中的作用

研究采用JAS范式,通过操纵群体信息的性质（支持和反对）以及一致性程度,考察了决策信心在信息化从众过程中的作用。结果表明：（1）个体仅在接收到反对信息时会发生决策的偏转,表现出从众;（2）群体参照信息能够显著影响个体的信心：支持性的群体信息使个体的信心显著增高,而反对性的群体信息使信心显著降低,且表现出一种“负性偏向”（即个体对来自群体的负性信息更加敏感）;（3）在反对条件下,个体信心降低的程度能够很好地预测其决策偏转的概率,即信息化从众行为。这说明,决策信心可能在信息化从众中起着核心的中介作用——反对性的群体信息使得决策信心下降,而决策信心的下降导致了决策的偏转,从而表现出从众行为。