Biasing the pacemaker in the behavioral theory of timing

In the behavioral theory of timing, pacemaker rate is determined by overall rate of reinforcement. A two-alternative free-operant psychophysical procedure was employed to investigate whether pacemaker period was also sensitive to the differential rate of reinforcement. Responding on a left key during the first 25 s and on a right key during the second 25 s of a 50-s trial was reinforced at variable intervals, and variable-interval schedule values during the two halves of the trials were varied systematically. Responding on the right key during the first 25 s and on the left key during the second 25 s was not reinforced. Estimates of pacemaker period were derived from fits of a function predicted by the behavioral theory of timing to right-key response proportions in consecutive 5-s bins of the 50-s trial. Estimates of pacemaker period were shortest when the differential reinforcer rate most strongly favored right-key responses, and were longest when the differential reinforcer rate most strongly favored left-key responses. The results were consistent with the conclusion that pacemaker rate is influenced by relative reinforcer rate.     

Temporal discrimination learning of operant feeding in goldfish (Carassius auratus)

Operant temporal discrimination learning was investigated in goldfish. In the first experiment, there was a fixed daily change in illumination. Eight subjects were trained to operate a lever that reinforced each press with food. The period during which responses were reinforced was then progressively reduced until it was 1 hr in every 24. The final 1-hr feeding schedule was maintained over 4 weeks. The feeding period commenced at the same time each day throughout. The food dispensers were then made inactive, and a period of extinction ensued for 6 days. The pattern of responding suggested that the fish were able to exhibit temporal discrimination in anticipation of feeding time. This pattern of responding persisted for a limited number of days during the extinction procedure. The second experiment produced evidence that operant temporal discrimination could develop under continuous illumination.     

时序信息提取机制的探索

对时序信息加工的经典研究是采用新近性判断范型,结果发现其提取机制是以新近性为基础的逆向串行搜索过程。本研究采用新近性判断范型和早远性判断范型对时序信息的提取机制进行了深入的考察,结果表明：（ｌ）提取时序信息既存在逆向串行搜索,又存在顺向串行搜索;（２）早远性判断和新近性判断任务对不同部分时序信息恢复的效应不同,其中早远性判断易化早远部分,新近性判断易化新近部分──表现为对相应部分辨别力的提高和正确反应潜伏期的缩短;（３）在不同的时序信息提取任务中,被试会根据具体条件进行反转反应。     

Temporal control of behavior: schedule interactions

In Experiment I the response that terminated the postreinforcement pauses occurring under a fixed-interval 60-second schedule was reinforced, if the pause duration exceeded 30 seconds. The percentage of such pauses, rather than increasing, decreased. There were complex effects on the discriminative control of the pause by the reinforcer terminating the previous fixed interval, depending on whether the fixed interval and the added reinforcer were the same or different. In Experiments II(a) and II(b), each reinforcement initiated an alternative fixed-interval interresponse-time-greater-than-t-sec schedule, the schedule values being systematically varied. When the response following a pause exceeding a given duration was reinforced, fewer such pauses occurred than when they were not reinforced, i.e., on the comparable simple fixed-interval schedule. There was no systematic relationship between mean interrinforcement interval and duration of the postreinforcement pause. The pause duration initiated by reinforcement was directly related to the dependency controlling the shortest pause at that time, regardless of changes in mean interreinforcement interval.     

Temporal control of behavior and the power law

The performance of rats and pigeons under fixed-interval schedules was studied in two experiments. The duration of postreinforcement pause was a declining proportion of fixed-interval duration. For pigeons this was true both when the duration of the reinforcer was fixed and when it was increased in direct proportion to increases in fixed-interval duration; the longer reinforcer durations did, however, lengthen the postreinforcement pause at higher schedule values. A quantitative analysis of data from Experiments 1 and 2 and from other studies showed that fractional exponent power functions described the relationship between postreinforcement pause and fixed-interval value; similar functions have previously been observed in studies of temporal differentiation. It was concluded that power functions reflect a direct causal, rather than artifactual, relationship between performance and the temporal requirements of reinforcement schedules.     

Rate and temporal pattern of key pecking under autoshaping and omission schedules of reinforcement

The role of response-reinforcer contiguity on autoshaped key pecking in pigeons was studied by scheduling response-dependent nonreinforcement at the beginning or the end of brief (8-sec) discrete trials. Schedules that permitted chance conjunctions of key pecking and food sustained high rates of responding, whereas those that prevented the occurrence of key peck-food intervals shorter than 4 sec sustained low response rates. In addition, selective reinforcement schedules supported accelerating or decelerating rates of responding within individual trials. These effects were traceable to response-reinforcer (operant), but not stimulus-reinforcer (respondent) factors.     

Food deliveries during the pause on fixed-interval schedules

Pigeons were trained on fixed-interval schedules of food delivery. In Experiments I and II, the fixed interval was initiated by the previous fixed-interval reinforcer; in Experiment III, the fixed interval was initiated by the first key peck following the preceding fixed-interval reinforcer (a chain fixed-ratio one, fixed-interval schedule). During the postreinforcement pause, variable-time schedules delivered food independent of any specific response. Rate of food delivery during the pause had only small effects on pause duration in Experiments I and II. In Experiment III, however, pause duration increased systematically with the rate of food delivery during the pause. These data suggest that the momentary proximity to reinforcement delivered via the fixed-interval schedule exerts potent control over pause termination. Additional analysis revealed that pause termination was unaffected by the intermittent delivery of food during the pause. Such data suggest that the temporal control by fixed-interval schedules is highly resistant to interference.     

发展性阅读障碍的听觉时间加工缺陷

发展性阅读障碍是指个体在智力正常并且不缺乏学校教育的情况下, 仍无法获得与年龄相匹配的阅读技能的一种学习障碍, 其缺陷的本质一直是研究者争论的焦点。大量研究显示, 阅读障碍者常表现出听觉时间加工损伤。在行为层面, 阅读障碍者难以辨别快速、连续呈现刺激的顺序以及刺激本身的动态时间特征。在神经层面, 阅读障碍者诱发的失匹配负波更弱且具有异常的神经同步加工。这些损伤同时存在于对言语和非言语刺激的加工中, 表明听觉时间加工缺陷非言语加工所特有。未来的研究还需阐明以下几个问题：1)阅读障碍的听觉时间加工缺陷发生在哪些时间窗口, 随年龄增长如何变化; 2)阅读障碍听觉时间加工缺陷在神经层面的时间进程是怎样的; 3)听觉时间加工缺陷是否为阅读障碍的核心缺陷。     

Longitudinal Development of Memory for Temporal Order in Early to Middle Childhood

Abstract

Existing studies examining the development of temporal order memory show that although young children perform above chance on some tasks assessing temporal order memory, there are significant age-related differences across childhood. Yet, the trajectory of children’s ability to retrieve temporal order remains unclear as existing conclusions are drawn from cross-sectional studies. The present study utilized an accelerated longitudinal design in order to characterize the developmental trajectory of temporal order memory in a sample of 200 healthy 4- to 8-year-old children. Specifically, two tasks commonly used in the literature were tested longitudinally: a primacy judgment task and an ordering task. Results revealed that, even after controlling for differences in IQ, linearly increasing trajectories characterized age-related change in performance for both tasks; however, change appeared greater for the temporal ordering task. Further, performance on the two tasks was positively related, suggesting shared underlying mechanisms. These findings provide a more thorough understanding of temporal order memory in early to middle childhood by characterizing the developmental trajectories of two commonly used tasks and have important implications for our understanding of children’s developing memory more broadly.