The effects of different instructions for preparatory muscle tension on simple reaction time

The effects of preparatory weak muscular contraction (pre-tension) have been investigated in a number of previous studies using tasks with either simple or choice responses to measure the reaction time (RT). These studies suggested that optimal pre-tension performed prior to a motor response tends to shorten the RTs. Using a simple RT task in which participants performed a grip response to a visual stimulus, the present study compared the RTs between two pre-tension conditions (self-selection and constraint) to investigate the effects of different instructions for pre-tension. Under the self-selection condition, participants were asked to determine their optimal pre-tension levels while attempting to give responses as fast as possible. Under the constraint condition, the participants developed a pre-tension at a target force determined by the experimenter. The target force was set at the same level as the pre-tension level maintained under the self-selection. Despite the fact that the pre-tension level manipulated was the same for both conditions, the RTs were significantly shorter under self-selection than under constraint. Moreover, the present study showed a positive correlation coefficient between the proportion of shortening in RT and the variation of pre-tension level. This indicated a performance trade-off between the stability of pre-tension and RTs. The result suggests that shorter RTs that occur under self-selection are primarily mediated by mental factors, such as attention allocation, rather than by the effects of peripheral muscular preparation.     

提取诱发遗忘中的情绪记忆权衡效应

情绪记忆的提取诱发遗忘研究是近年来记忆研究领域的热点问题,但是尚无一致的结果。在现实生活中,我们所面临的情绪事件十分复杂,不仅包含核心的情绪信息,还包括边缘非情绪信息,研究已发现,人们对于这些复杂情绪事件不同成分的记忆效果也不是完全相同的。本研究通过2个实验分别探讨提取练习整张复杂情绪图片和提取练习复杂情绪图片的背景成分时的提取诱发遗忘现象。结果表明:(1)无论提取练习完整信息还是相关的边缘信息,均在提取诱发遗忘中存在显著的情绪记忆权衡效应;(2)消极情绪项目像中性项目一样也能产生提取诱发遗忘效应;(3)不论提取图片的完整信息还是背景信息,都仅在中心项目上表现出提取诱发遗忘,边缘背景没有出现提取诱发遗忘。     

意识和无意识权衡现象的四个特征

本实验以探讨意识和无意识之间的复杂关系为目的 ,采用 5 (年龄 :老年、中年、大学生、初三和高小 )× 2 (贡献来源 :意识和无意识 )的两因素混合设计 ,通过加工分离程序 (PDP)的包含和排除测验 ,计算意识和无意识的贡献大小。结果表明在对具体图片的记忆中 ,1)意识和无意识贡献出现了发展上的分离 ;2 )老年组的无意识贡献高于意识贡献 ,但未达到显著水平 ,其余四个组别则表现出意识贡献水平极其显著地高于无意识贡献水平。在此基础上 ,本研究对意识和无意识的权衡现象的四个特征 (相互独立、相互作用、互为主次、互相依存 )分别进行了阐述     

Precision and accuracy of judgmental estimation

Whereas probabilistic calibration has been a central normative concept of accuracy in previous research on interval estimates, we suggest here that normative approaches for the evaluation of judgmental estimates should consider the communicative interaction between the individuals who produce the judgments and those who receive or use them for making decisions. We analyze precision and error in judgment and consider the role of the accuracy–informativeness trade-off (Yaniv and Foster, 1995) in the communication of estimates. The results shed light on puzzling findings reported earlier in the literature concerning the calibration of subjective confidence intervals. © 1997 John Wiley & Sons, Ltd.     

Hick’s law equivalent for reaction time to individual stimuli

Hick’s law, one of the few law-like relationships involving human performance, expresses choice reaction time as a linear function of the mutual information between the stimulus and response events. However, since this law was first proposed in 1952, its validity has been challenged by the fact that it only holds for the overall reaction time (RT) across all the stimuli, and does not hold for the reaction time (RT_i) for each individual stimulus. This paper introduces a new formulation in which RT_i is a linear function of (1) the mutual information between the event that stimulus i occurs and the set of all potential response events and (2) the overall mutual information for all stimuli and responses. Then Hick’s law for RT follows as the weighted mean of each side of the RT_i equation using the stimulus probabilities as the weights. The new RT_i equation incorporates the important speed–accuracy trade-off characteristic. When the performance is error-free, RT_i becomes a linear function of two entropies as measures of stimulus uncertainty or unexpectancy. Reanalysis of empirical data from a variety of sources provide support for the new law-like relationship.     

Assessing the evidence for a cue-induced trade-off between capacity and precision in visual working memory using mixture modelling and Bayesian model comparison

There is considerable debate regarding the ability to trade mnemonic precision for capacity in working memory (WM), with some studies reporting evidence consistent with such a trade-off and others suggesting it may not be possible. The majority of studies addressing this question have utilized a standard approach to analysing continuous recall data in which individual-subject data from each experimental condition is fitted with a probabilistic model of choice. Estimated parameter values related to different aspects of WM (e.g., the capacity and precision of stored items) are then compared using statistical tests to determine the presence of hypothesized differences between experimental conditions. However, recent research has suggested that the standard approach is flawed in several respects. In this study, we presented participants with behavioural pre-cues informing them about the upcoming number of to-be-remembered items (high- vs. low-load) with the goal of inducing a trade-off between capacity and precision. The data were then analysed using the standard analytical approach and a more rigorous Bayesian model comparison (BMC) approach. The second approach involved generating a set of probabilistic models whose priors reflect different hypotheses regarding the effect of our key experimental manipulations on behaviour. Our results demonstrate that these two approaches can produce notably different results. More specifically, the standard analysis revealed that a high- versus a low-load cue resulted in higher capacity and lower precision parameter estimates, suggesting the presence of a trade-off between capacity and precision. However, the more rigorous BMC analysis revealed that it was very unlikely that participants employed a behavioural strategy in which they sacrificed mnemonic precision to achieve higher storage capacity. In light of these differences, we advocate for a more stringent approach to model selection and hypothesis testing in studies implementing mixture modelling.     

预期惩罚调节认知控制权衡：来自行为和fNIRS的证据

为了探讨预期惩罚是如何影响认知控制权衡,本研究采用fNIRS技术考察被试在完成有惩罚和无惩罚AX-CPT任务时的行为表现和大脑激活模式。行为结果发现：与无惩罚的基线条件相比,惩罚条件下个体偏向主动性控制。脑成像结果发现：与无惩罚的基线条件相比,惩罚条件下大脑前额叶皮层在线索阶段处于负激活状态。这说明,惩罚条件下在线索阶段个体需要更多的注意资源,因此,脑成像的结果也表明惩罚使被试更偏向主动性控制。     

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.     

Do humans produce the speed–accuracy trade-off that maximizes reward rate?

In this paper we investigate trade-offs between speed and accuracy that are produced by humans when confronted with a sequence of choices between two alternatives. We assume that the choice process is described by the drift diffusion model, in which the speed–accuracy trade-off is primarily controlled by the value of the decision threshold. We test the hypothesis that participants choose the decision threshold that maximizes reward rate, defined as an average number of rewards per unit of time. In particular, we test four predictions derived on the basis of this hypothesis in two behavioural experiments. The data from all participants of our experiments provide support only for some of the predictions, and on average the participants are slower and more accurate than predicted by reward rate maximization. However, when we limit our analysis to subgroups of 30–50% of participants who earned the highest overall rewards, all the predictions are satisfied by the data. This suggests that a substantial subset of participants do select decision thresholds that maximize reward rate. We also discuss possible reasons why the remaining participants select thresholds higher than optimal, including the possibility that participants optimize a combination of reward rate and accuracy or that they compensate for the influence of timing uncertainty, or both.