跨期选择中的年龄差异及其机制

随着老龄化形势日益严峻, 老年人的跨期选择受到越来越多学者的关注。目前关于跨期选择的年老化研究尚存分歧:有研究发现老年人比年轻人更偏好未来获得更大收益; 也有研究发现老年人的选择偏好和年轻人一样, 甚至比年轻人更偏好近期收益。从时间表征和结果价值表征两个维度上的加工过程去分析其对老年人跨期选择的影响, 并进一步阐述认知、动机和情绪因素对两个维度加工过程的影响, 这对于理解当前老年人跨期选择领域研究的分歧有重要科学意义。     

Crossmodal temporal order and processing acuity in developmentally dyslexic young adults

We investigated crossmodal temporal performance in processing rapid sequential nonlinguistic events in developmentally dyslexic young adults (ages 20-36 years) and an age- and IQ-matched control group in audiotactile, visuotactile, and audiovisual combinations. Two methods were used for estimating 84% correct temporal acuity thresholds: temporal order judgment (TOJ) and temporal processing acuity (TPA). TPA requires phase difference detection: the judgment of simultaneity/nonsimultaneity of brief stimuli in two parallel, spatially separate triplets. The dyslexic readers' average temporal performance was somewhat poorer in all six comparisons; in audiovisual comparisons the group differences were not statistically significant, however. A principal component analysis indicated that temporal acuity and phonological awareness are related in dyslexic readers. The impairment of temporal input processing seems to be a general correlative feature of dyslexia in children and adults, but the overlap in performance between dyslexic and normal readers suggests that it is not a sufficient reason for developmental reading difficulties.     

小学儿童对日常生活事件时间关系推理能力的初探

探查小学儿童对含有“在什么之前”“同时”日常生活事件时间关系的推理发展过程及其影响因素。被试为7岁、9岁、11岁3个年龄组共54名小学儿童,每个年龄组18人。4种问题模式分别为带有传递关系的单模型问题、带有无关前提的单模型问题、含两个前提的单模型问题、有肯定答案的多模型问题。每种问题模式含3种具体探察任务。主要研究结果表明：在本实验条件下,（1）儿童对事件时间顺序关系的推理从7岁到9岁有快速发展的趋势;（2）单模型和多模型任务无显著差异,模型数量似乎不是影响儿童推理成绩的关键因素;（3）儿童能够主动采用5种策略解决问题。逆向关系传递策略是问题解决的有效策略。     

Effects of reinforcement history on response rate and response pattern in periodic reinforcement

Several researchers have suggested that conditioning history may have long-term effects on fixed-interval performances of rats. To test this idea and to identify possible factors involved in temporal control development, groups of rats initially were exposed to different reinforcement schedules: continuous, fixed-time, and random-interval. Afterwards, half of the rats in each group were studied on a fixed-interval 30-s schedule of reinforcement and the other half on a fixed-interval 90-s schedule of reinforcement. No evidence of long-term effects attributable to conditioning history on either response output or response patterning was found; history effects were transitory. Different tendencies in trajectory across sessions were observed for measures of early and late responding within the interreinforcer interval, suggesting that temporal control is the result of two separate processes: one involved in response output and the other in time allocation of responding and not responding.     

Prefrontal brain activity predicts temporally extended decision-making behavior

Although functional neuroimaging studies of human decision-making processes are increasingly common, most of the research in this area has relied on passive tasks that generate little individual variability. Relatively little attention has been paid to the ability of brain activity to predict overt behavior. Using functional magnetic resonance imaging (fMRI), we investigated the neural mechanisms underlying behavior during a dynamic decision task that required subjects to select smaller, short-term monetary payoffs in order to receive larger, long-term gains. The number of trials over which the longterm gains accrued was manipulated experimentally (2 versus 12). Event-related neural activity in right lateral prefrontal cortex, a region associated with high-level cognitive processing, selectively predicted choice behavior in both conditions, whereas insular cortex responded to fluctuations in amount of reward but did not predict choice behavior. These results demonstrate the utility of a functional neuroimaging approach in behavioral psychology, showing that (a) highly circumscribed brain regions are capable of predicting complex choice behavior, and (b) fMRI has the ability to dissociate the contributions of different neural mechanisms to particular behavioral tasks.     

Educational Expectations and School Achievement of Urban African American Children

The mechanisms used to convey parents' and teachers' educational expectations for the academic achievement of low-income African American children were explored using data from the Chicago Longitudinal Study. A total of 712 children were studied. A model of mediated effects was used to test the processes of influence from parents' and teachers' expectations to sixth-grade outcomes. Children's perceptions of expectations were hypothesized to mediate the effect of expectations to school outcomes. Study findings revealed that these perceptions only partially mediated the effects of expectations to sixth-grade reading and math outcomes, yet added unique independent variance to these outcomes. Prior achievement emerged as a powerful mediator of the effects of early educational intervention and sociodemographic variables to sixth-grade outcomes. These findings suggest a need to further investigate the processes of communicating parent and teacher expectations.     

时间记忆层次网络模型的实验检验

实验采用分类性实验材料,使被试在对词单项目加工时形成较清晰的群集,进而形成时间组块,目的在于对时间记忆层次网络进行直接检验。其中时序判断用反时间时和正确率两种反应指标,时距估计用再现和口头估计两种方法。结果发现,时间信息记忆既存在层次网络的特征,又存在线性结构的特征。