Do learning-disabled children exhibit peripheral deficits in selective attention? An analysis of eye movements during reading

It has been suggested that deficits in selective attention play a functional role in the learning and behavior problems of children diagnosed as learning- disabled. In the present study, peripheral and central aspects of selective attention were distinguished and peripheral aspects were examined. The attending eye movements during reading of 12 fifth-grade learning-disabled children who read at the third-grade level were compared with 12 fifth-grade children who read at the fifth-grade level (grade placement controls) and 12 third-grade children who read at the third-grade level (reading level controls). The learning-disabled children did not differ from their reading level controls on any of W measures but showed a pattern of eye movements that was generally slower and less smooth than their grade placement controls. While these patterns might be considered to be immature relative to normal readers of the same age, they are not indicative of peripheral deficits in selective attention. Males, however, did exhibit more variability in duration of fixations and made more regressive eye movements than did females.     

The conditioning of textual responses using “extrinsic” reinforcers

Six 4-year-old Ss were presented with a textual program consisting of 26 words arranged so the word stimuli were gradually combined into sentences and then short “stories.” Three Ss were given the No-Reinforcement condition first, and only social reinforcers were presented. They were switched to the Reinforcement condition as soon as they requested discontinuance of the activity. The other three Ss were given Reinforcement—No Reinforcement—Reinforcement treatments. The No-Reinforcement treatment in this case lasted until S requested discontinuance of the activity. The reinforcers were mixed edibles and trinkets, as well as tokens backed up by small plastic toys on a 1:24 ratio. The unit of response was the number of new texts acquired as a result of each of the 45-min experimental sessions. It was demonstrated that the program, procedure, and reinforcement conditions produced curves which are analogous to those produced in common operant-conditioning procedures. The results indicate that other operant principles may be studied in this significant area of human behavior, with important practical consequences.     

一种对动物学习记忆能力突变筛查的新途

本文详细描述了一种全自动化的行为检测方案。在自然饲养环境/检测环境(24/7)中, 我们测量了小鼠针对两个给食器中获得食物的比例与它们在相应给食器停留时长的比例进行匹配的精确性与准确性。该方案是对传统条件性习得 (trials-to-acquisition) 行为测验设备的改进, 可以检测动物时间间隔能力的精确性与准确性, 对定时目标选择的相关概率的效果, 以及记忆一天中从不同给食器中获得食物次数的精确性与准确性。该压缩系统避免了在整个实验过程中对小鼠的持握操作, 可忽略实验者/技术员的实验操作时间, 而且可以递送小鼠置入实验环境后, 7~9个实验日中全部3组实验流程产生的大量结果。其中, 第一个实验流程为单个24小时周期内完成的时间匹配能力的筛查, 它对动物的时间、空间估计能力的记忆机制进行精确检测。因此, 该系统允许在有限的实验空间、较短的实验周期内, 对大量的实验小鼠进行有可能存在的学习记忆能力缺陷进行大规模筛查。此外, 该系统运行所依赖的软件可以在公共开放平台获得。