Judgments of reachability are independent of visuomotor adaptation

The furthest distance that is judged to be reachable can change after participants have used a tool or if they are led to misjudge the position of their hand. Here we investigated how judged reachability changed when visual feedback about the hand was shifted. We hoped to distinguish between various ways in which visuomotor adaptation could influence judged reachability. Participants had to judge whether they could reach a virtual cube without actually doing so. They indicated whether they could reach this virtual cube by moving their hand. During these hand movements, visual feedback about the position of the hand was shifted in depth, either away from or toward the participant. Participants always adapted to the shifted feedback. In a session in which the hand movements in the presence of visual feedback were mainly in depth, perceived reachability shifted in accordance with the feedback (more distant cubes were judged to be reachable when feedback was shifted further away). In a second session in which the hand movements in the presence of visual feedback were mainly sideways, for some participants perceived reachability shifted in the opposite direction than we expected. The shift in perceived reachability was not correlated with the adaptation to the shift in visual feedback. We conclude that reachability judgments are not directly related to visuomotor adaptation.     

The influence of prior knowledge on the retrieval‐directed function of note taking in prior knowledge activation

Background. Prior knowledge activation facilitates learning. Note taking during prior knowledge activation (i.e., note taking directed at retrieving information from memory) might facilitate the activation process by enabling learners to build an external representation of their prior knowledge. However, taking notes might be less effective in supporting prior knowledge activation if available prior knowledge is limited. Aims. This study investigates the effects of the retrieval‐directed function of note taking depending on learners' level of prior knowledge. It is hypothesized that the effectiveness of note taking is influenced by the amount of prior knowledge learners already possess. Sample. Sixty‐one high school students participated in this study. A prior knowledge test was used to ascertain differences in level of prior knowledge and assign participants to a low or a high prior knowledge group. Method. A 2×2 factorial design was used to investigate the effects of note taking during prior knowledge activation (yes, no) depending on learners' level of prior knowledge (low, high) on mental effort, performance, and mental efficiency. Results. Note taking during prior knowledge activation lowered mental effort and increased mental efficiency for high prior knowledge learners. For low prior knowledge learners, note taking had the opposite effect on mental effort and mental efficiency. Conclusions. The effects of the retrieval‐directed function of note taking are influenced by learners' level of prior knowledge. Learners with high prior knowledge benefit from taking notes while activating prior knowledge, whereas note taking has no beneficial effects for learners with limited prior knowledge.     

Timing the moment of impact in fast human movements

The reported resolution of timing the moment of impact in fast human movements differs widely depending on the task. Surprisingly, better timing is reported for the demanding task of batting a ball than for the much simpler task of tapping in synchrony with two hands. We wondered whether this is because a sizeable part of timing variability arises from misjudging the distance in the direction of one's own movement, so that moving faster (as the bat does when moving toward a ball) improves timing. We found that moving faster does indeed improve timing in both the above-mentioned tasks. After removing the proposed contribution of misjudging the distance in the direction of one's own movement, we estimated that the remaining standard deviation in timing is just over 6ms for both tasks.     

Beliefs about the social orientations of others: A parametric test of the triangle,false consensus,and cone hypotheses

This study tests a number of hypotheses proposed in the literature concerning the relationship between an actor's social orientation and her beliefs about the social orientations of others. In contrast to the existing literature, this study employs a parametric approach with an innovative methodology. First, the social orientation parameters of actors are estimated: the weights respondents add to (1) the outcomes of Alter and to (2) the absolute difference between the outcomes for Ego and Alter. Then, the mean and the variance of the distribution of beliefs about the social orientation parameters of others are estimated, conditional on the actor's social orientation parameters. The results show that (1) there is a positive association between an actor's social orientation and her belief about the mean of the social orientations of others and (2) those who have approximately zero social orientation parameter values (individualists) expect the variation of others' social orientations to be lower than those with smaller (competitors) or larger (cooperators/egalitarians) social orientation parameter values. These results support the cone model, which models the “false” consensus effect where the “false” consensus is highest for individualists.     

Retrieval-induced forgetting without competition: Testing the retrieval specificity assumption of the inhibition theory

According to the inhibition theory of forgetting (Anderson, Journal of Memory and Language 49:415–445, 2003; Anderson, Bjork, & Bjork, Psychonomic Bulletin & Review 7:522-530, 2000), retrieval practice on a subset of target items leads to forgetting for the other, nontarget items, due to the fact that these other items interfere during the retrieval process and have to be inhibited in order to resolve the interference. In this account, retrieval-induced forgetting occurs only when competition takes place between target and nontarget items during target item practice, since only in such a case is inhibition of the nontarget items necessary. Strengthening of the target item without active retrieval should not lead to such an impairment. In two experiments, we investigated this assumption by using noncompetitive retrieval during the practice phase. We strengthened the cue–target item association during practice by recall of the category name instead of the target item, and thus eliminated competition between the different item types (as in Anderson et al., Psychonomic Bulletin & Review 7:522-530 2000). In contrast to the expectations of the inhibition theory, retrieval-induced forgetting occurred even without competition, and thus the present study does not support the retrieval specificity assumption.     

Automatic Priming Effects for New Associations in Lexical Decision and Perceptual Identification

Information storage in semantic memory was investigated by looking at automatic priming effects for new associations in two experiments. In the study phase, word pairs were presented in a paired-associate learning task. Lexical decision and perceptual identification were used to examine priming effects during and after the study phase. There was automatic priming for new associations. The priming effect was greatly reduced when different semantic tasks were used at study and test compared to when identical tasks were used at study and test. The results show that new associations in semantic memory can be accessed automatically but are still context dependent. This suggests that rather than being abstract and static, retrieval from semantic memory interacts dynamically with the context.     

Multi-target visual search organisation across the lifespan: cancellation task performance in a large and demographically stratified sample of healthy adults

Accurate tests of cognition are vital in (neuro)psychology. Cancellation tasks are popular tests of attention and executive function, in which participants find and ‘cancel’ targets among distractors. Despite extensive use in neurological patients, it remains unclear whether demographic variables (that vary among patients) affect cancellation performance. Here, we describe performance in 523 healthy participants of a web-based cancellation task. Age, sex, and level of education did not affect cancellation performance in this sample. We provide norm scores for indices of spatial bias, perseverations, revisits, processing speed, and search organisation. Furthermore, a cluster analysis identified four cognitive profiles among participants, characterised by many omissions (N=18), many revisits (N=18), relatively poor search organisation (N=125), and relatively good search organisation (N=362). Thus, patient scores pertaining to search organisation should be interpreted cautiously: Given the large proportion of healthy individuals with poor search organisation, disorganised search in patients might be pre-existing rather than disorder-related.     

纳米药物的风险及控制

纳米技术在药学领域的应用表现为药物的靶向传递和纳米级粒子药物.纳米药物的风险表现为对人健康的风险和对环境损害的风险.应对纳米药物带来的风险和伦理问题,需要创建风险评估标准;维护人的知情权和自主权;遵守自然规律,严格规范生产设计;强化政策导向、监督管理和法律保障.