Absence of Ankle Stiffening While Standing in Focus and Cognitive Task Conditions in Older Adults

Abstract

Research suggests that an external focus or cognitive task may improve postural control. Removing attention from movement production may promote automaticity, or the tasks may promote ankle stiffening. To investigate these two theories, twenty older adults stood while performing baseline standing, internal focus, external focus, and two cognitive tasks. Changes in postural control occurred in external focus and cognitive task conditions compared to baseline and internal focus, while no change occurred in cocontraction indices. This suggests that an external focus and cognitive task can improve postural control in older adults. Since no change occurred in cocontraction indices across conditions, this suggests that stiffening cannot explain these changes. Instead, changes could be due to automaticity of sway.     

提取干扰对内隐记忆的影响

以往研究多认同内隐记忆不会受到干扰的影响,但主要集中于编码时的干扰不会影响随后的内隐记忆提取成绩,而对于提取时的干扰是否也不会影响内隐记忆成绩仍存在疑义。该文在实验1采用学习-测验范式,通过在提取阶段设置同时干扰任务进一步考察提取干扰与内隐记忆的关系,结果表明提取干扰下并未发现明显的启动效应,即提取干扰破坏了内隐记忆。为进一步探讨内隐记忆的提取干扰效应是否源于记忆与干扰刺激同时呈现所引起的知觉表征竞争,实验2改变了记忆与干扰刺激的呈现顺序,结果表明不论干扰刺激在记忆项目之前或之后呈现,启动效应均受到影响。相比之下,提取干扰对再认成绩的影响并不明显(实验3)。上述结果表明,内隐记忆的提取干扰效应是源于一般认知资源的竞争,在提取过程中任何能够产生认知资源竞争的变量设置都可能会削减内隐测验中的启动效应。     

Directed forgetting of negative performed actions is difficult: A behavioural study

Strong evidence suggests that both performing actions and emotional stimuli can enhance memory by capturing attention. However, the synergetic effect of the two factors on directed forgetting has not been assessed. In this study, we used an item-method directed forgetting paradigm to examine the forgetting of emotional materials depending on whether actions were performed. The results showed that action performance influenced the directed forgetting of emotional words. Specifically, when actions were performed there was a directed forgetting effect for neutral and positive words but not for negative words. In comparison, for verbal tasks, directed forgetting was observed for all words. The elaborative encoding prior to the remember/forget instructions and the influence of negative emotion on attentional inhibition after the presentation of the instructions together suggest that it is more difficult to intentionally forget negative performed actions.     

真实和虚拟金钱奖赏影响风险决策行为*

在风险情境下人类如何决策是长久以来心理学和经济学研究中一个极具挑战性的核心问题。众多研究采用真实或虚拟金钱作为奖赏强化物来探索风险决策行为的过程和机制,但对金钱奖赏真实性如何影响决策了解很少。仿真气球冒险任务(BART：Balloon Analogue Risk Task)可以在实验室条件下有效评估个体在真实社会中的风险行为。本研究采用 BART任务,通过两个实验探讨和比较了真实与虚拟金钱奖赏对风险决策行为的影响。实验一的结果发现,与虚拟金钱奖赏相比,真实金钱奖赏情境下的风险决策更容易受上一次决策结果的影响,上一次决策失败会导致被试的风险偏好水平显著降低(平均吹气球的次数显著减少),同时决策失败(气球吹爆)次数也显著减少,提示真实金钱奖赏下有更强的反馈学习效应。实验二重复了实验一的结果,并进一步发现,虚拟金钱奖赏的幅度对被试的风险决策行为没有影响,而真实金钱奖赏的幅度能显著改变被试的风险决策行为,较大幅度的真实金钱奖赏可以显著降低被试的风险偏好水平,但这种奖赏幅度对风险偏好的调控效应只对感觉寻求水平低的被试有效,感觉寻求水平高的被试不受影响。这些发现表明真实与虚拟金钱奖赏对风险决策行为有不同的影响。我们的结果可以用风险决策的后悔理论或齐当别模型来解释。     

Developmental differences in working memory: Where do they come from?

Several models assume that working memory development depends on age-related increases in efficiency and speed of processing. However, age-related increases in the efficiency of the mechanisms that counteract forgetting and restore memory traces may also be important. This hypothesis was tested in three experiments by manipulating both the processing duration within a working memory task and the time available to restore memory traces. Third- and sixth-grade children performed a complex span task in which they maintained series of letters while adding numbers to series of digits. When we equated processing and restoration times between ages, the developmental difference in working memory span was reduced but remained significant. However, this residual difference was eliminated when the time available to reactivate memory traces was tailored to the processing speed of each age group. This indicates that children employ active mechanisms for maintenance and restoration of memory traces that develop with age.     

Representation of objects and events: why do infants look so smart and toddlers look so dumb?

Research has demonstrated that very young infants can discriminate between visual events that are physically impossible versus possible. These findings suggest that infants have knowledge of physical laws concerning solidity and continuity. However, research with 2-year-olds has shown that they cannot solve simple problems involving search for a hidden object, even though these problems require the same knowledge. These apparently inconsistent findings raise questions about the interpretation of both data sets. This discrepancy may be resolved by examining differences in task demands.     

金钱刺激和决策者角色对个体道德决策的影响——基于过程分离范式

以大学生为被试,采用3（金钱刺激：无金钱刺激、金钱奖励、金钱惩罚）×2（决策者角色：决策者、旁观者）的被试间实验设计,利用过程分离范式分别计算被试道德决策中的功利主义倾向和道义论倾向,从而探讨金钱刺激和决策者角色对个体道德决策的影响。结果发现：（1）无论是决策者还是旁观者,金钱刺激都不会影响其道义论倾向;（2）决策者的道义论倾向大于旁观者;（3）只在有金钱奖励时决策者的功利主义倾向才大于旁观者。     

金钱激励在社会排斥影响不确定性决策中的调节作用

研究从金钱补偿的视角考察社会排斥对不确定性决策的影响以及金钱激励的调节作用。实验发现,有金钱激励时,被排斥者在爱荷华赌博任务(Iowa gambling task,IGT)中的行为分数(组块2和3的选牌净分数和总的盈利分数)显著高于社会接纳者,表现为风险规避; 在无金钱激励时,被排斥者在IGT任务中的行为分数(组块4和5的选牌净分数和总的盈利分数)显著低于被接纳者,表现为风险寻求。实验结果表明社会排斥对不确定性决策的影响受到金钱激励的调制。     

金钱惩罚促进Stroop任务中的行为表现

本研究通过Stroop任务和修改版MIDT相结合,目的是考察不同额度金钱惩罚对Stroop任务行为表现的影响。结果发现：（1）无论是中性试次,一致试次还是不一致试次,金钱惩罚不仅减少了被试的行为反应时,而且提高了正确率;（2）非惩罚条件与惩罚条件下的冲突效应以及其他不同额度惩罚条件下的冲突效应差异不显著;（3）金钱惩罚对不一致试次反应时的影响与个体的惩罚敏感性呈显著负相关,而与奖赏敏感性无关。结果表明,金钱惩罚能够促进个体的一般行为表现,但是不会提高冲突抑制能力。同时,金钱惩罚对认知行为的影响与其惩罚敏感性密切相关。     

Slow and steady? Strategic adjustments in response caution are moderately reliable and correlate across tasks

Speed-accuracy trade-offs are often considered a confound in speeded choice tasks, but individual differences in strategy have been linked to personality and brain structure. We ask whether strategic adjustments in response caution are reliable, and whether they correlate across tasks and with impulsivity traits. In Study 1, participants performed Eriksen flanker and Stroop tasks in two sessions four weeks apart. We manipulated response caution by emphasising speed or accuracy. We fit the diffusion model for conflict tasks and correlated the change in boundary (accuracy – speed) across session and task. We observed moderate test-retest reliability, and medium to large correlations across tasks. We replicated this between-task correlation in Study 2 using flanker and perceptual decision tasks. We found no consistent correlations with impulsivity. Though moderate reliability poses a challenge for researchers interested in stable traits, consistent correlation between tasks indicates there are meaningful individual differences in the speed-accuracy trade-off.