Learning to allocate limited time to decisions with different expected outcomes

The goal of this article is to investigate how human participants allocate their limited time to decisions with different properties. We report the results of two behavioral experiments. In each trial of the experiments, the participant must accumulate noisy information to make a decision. The participants received positive and negative rewards for their correct and incorrect decisions, respectively. The stimulus was designed such that decisions based on more accumulated information were more accurate but took longer. Therefore, the total outcome that a participant could achieve during the limited experiments’ time depended on her “decision threshold”, the amount of information she needed to make a decision. In the first experiment, two types of trials were intermixed randomly: hard and easy. Crucially, the hard trials were associated with smaller positive and negative rewards than the easy trials. A cue presented at the beginning of each trial would indicate the type of the upcoming trial. The optimal strategy was to adopt a small decision threshold for hard trials. The results showed that several of the participants did not learn this simple strategy. We then investigated how the participants adjusted their decision threshold based on the feedback they received in each trial. To this end, we developed and compared 10 computational models for adjusting the decision threshold. The models differ in their assumptions on the shape of the decision thresholds and the way the feedback is used to adjust the decision thresholds. The results of Bayesian model comparison showed that a model with time-varying thresholds whose parameters are updated by a reinforcement learning algorithm is the most likely model. In the second experiment, the cues were not presented. We showed that the optimal strategy is to use a single time-decreasing decision threshold for all trials. The results of the computational modeling showed that the participants did not use this optimal strategy. Instead, they attempted to detect the difficulty of the trial first and then set their decision threshold accordingly.     

Information‐Theoretic Measures Predict the Human Judgment of Rhythm Complexity

To formalize the human judgment of rhythm complexity, we used five measures from information theory and algorithmic complexity to measure the complexity of 48 artificially generated rhythmic sequences. We compared these measurements to human prediction accuracy and easiness judgments obtained from a listening experiment, in which 32 participants guessed the last beat of each sequence. We also investigated the modulating effects of musical expertise and general pattern identification ability. Entropy rate and Kolmogorov complexity were correlated with prediction accuracy, and highly correlated with easiness judgments. A logistic regression showed main effects of musical training, entropy rate, and Kolmogorov complexity, and an interaction between musical training and both entropy rate and Kolmogorov complexity. These results indicate that information‐theoretic concepts capture some salient features of the human judgment of rhythm complexity, and they confirm the influence of musical expertise on complexity judgments.     

应变率显像评价尿毒症EF正常患者左心室局部功能

为探讨应变率显像(SRI)技术评价尿毒症左心室射血分数(EF)正常患者左心室局部功能的价值,对41例尿毒症EF正常患者及20例健康自愿者左心室心肌纵向SRI曲线进行分析,测量各曲线收缩峰值应变率(SRs)、舒张早期峰值应变率(SRe)、舒张晚期峰值应变率(SRa)并计算SRe/SRa。结果显示,尿毒症组左心室各节段SRs、SRe、SRe/SRa均低于对照组(P0.05)。因此,尿毒症EF正常患者已经存在局部心肌舒缩功能障碍,并且这种障碍可以被SRI技术敏感、定量地评价。     

理性看待心房颤动导管消融成功率

随着心房颤动导管消融术的发展,其成功率不断提高,但医学上的消融成功并不一定等同于永久性治愈,且由于心房颤动的复杂性、消融终点多元性、不规范的术后随访制度和医疗体制不合理等诸多因素影响,导管消融成功率往往被无意或有意夸大,术后可能会因为达不到患者期望值而产生医疗纠纷。     

Treating chronic worry: Psychological and physiological effects of a training programme based on mindfulness

The present study examines psychological and physiological indices of emotional regulation in non-clinical high worriers after a mindfulness-based training programme aimed at reducing worry. Thirty-six female university students with high Penn State Worry Questionnaire scores were split into two equal intervention groups: (a) mindfulness, and (b) progressive muscle relaxation plus self-instruction to postpone worrying to a specific time of the day. Assessment included clinical questionnaires, daily self-report of number/duration of worry episodes and indices of emotional meta-cognition. A set of somatic and autonomic measures was recorded (a) during resting, mindfulness/relaxation and worrying periods, and (b) during cued and non-cued affective modulation of defence reactions (cardiac defence and eye-blink startle). Both groups showed equal post-treatment improvement in the clinical and daily self-report measures. However, mindfulness participants reported better emotional meta-cognition (emotional comprehension) and showed improved indices of somatic and autonomic regulation (reduced breathing pattern and increased vagal reactivity during evocation of cardiac defense). These findings suggest that mindfulness reduces chronic worry by promoting emotional and physiological regulatory mechanisms contrary to those maintaining chronic worry.     

Psychophysiological reactivity to sleep-related emotional stimuli in primary insomnia

The present study examined psychophysiological reactivity to emotional stimuli related and non-related to sleep in people with primary insomnia (PPI) and in good sleepers (GS). Twenty-one PPI and 18 GS were presented with five blocks of neutral, negative, positive, sleep-related negative and sleep-related positive pictures. During the presentation of the pictures, facial electromyography (EMG) of the corrugator and the zygomatic muscles, heart rate (HR) and cardiac vagal tone (CVT) were recorded. Subjective ratings of the stimuli were also collected. We found that only PPI exhibited greater inhibition of the corrugator activity in response to sleep-related positive stimuli compared to the other blocks of stimuli. Furthermore, PPI rated the sleep-related negative stimuli as more unpleasant and arousing and showed higher CVT in response to all stimuli as compared to GS. Results were interpreted as indicating that PPI exhibit craving for sleep-related positive stimuli, and also hyper-arousability in response to sleep-related negative stimuli, as compared to GS. Our results suggest that psychological treatment of insomnia could benefit by the inclusion of strategies dealing with emotional processes linked with sleep processes.     

应激干预对不同行为类型大学生心率血压手指温度的影响

探讨应激干预对心率、血压、手指温度的影响及不同行为类型的差异。被试为河北师范大学本科生72人(A、B型各36人),应激干预为音乐放松、腹式呼吸和静坐休息,实验包括基线期-干预期-应激期-恢复期四个阶段,在观看紧张性影片前进行应激前干预,记录被试的心率、血压、手指温度。结果发现,就缓解应激所产生的交感神经活动增强来说,音乐放松效果较好,腹式呼吸也明显优于自然休息;行为类型（A、B）和应激干预大多表现出来交互作用;个体生理反应的性别差异与生理指标有关,基线值的性别差异较大时,男女生的生理数据不宜混合在一起,基线值相差不大时,可以用相对值（如变化值或变化率）进行统计处理。说明行为类型（A、B）对于应激而言是一种微调变量,在自然休息状态或者低应激水平下作用更明显,应激水平较高时,行为类型的调节作用会显著降低;不同应激干预适用不同行为类型个体     

降压治疗的决策思考

尽管降压药物有了很大发展,高血压的控制率仍很低下。降压治疗中还存在包括医生和患者两方面的许多误区。目前已取得的共识是:降压治疗的益处主要来自血压控制。因此,非常重要的是要达到血压的有效和长期稳定的降低。根据患者的年龄、基线血压、伴随的临床状况等,因人而异地选择副作用小、降压效果好的药物,提高顺应性是改善高血压控制率的关键。     

The effect of reinforcement probability on time discrimination in the midsession reversal task

We examined how biasing time perception affects choice in a midsession reversal task. Given a simultaneous discrimination between stimuli S1 and S2, with choices of S1 reinforced during the first, but not the second half of the trials, and choices of S2 reinforced during the second, but not the first half of the trials, pigeons show anticipation errors (premature choices of S2) and perseveration errors (belated choices of S1). This suggests that choice depends on timing processes, on predicting when the contingency reverses based on session duration. We exposed 7 pigeons to a midsession reversal task and manipulated the reinforcement rate on each half of the session. Compared to equal reinforcement rates on both halves of the session, when the reinforcement rate on the first half was lower than on the second half, performance showed more anticipation and less perseveration errors, and when the reinforcement rate on the first half was higher than on the second half, performance showed a remarkable reduction of both types of errors. These results suggest that choice depends on both time into the session and the outcome of previous trials. They also challenge current models of timing to integrate local effects.