GENERALIZED IMITATION AND RESPONSE-CLASS FORMATION IN CHILDREN WITH AUTISM

An experimental analysis of imitation was conducted to examine the influence of response topography on generalization of imitation across three response types. Four children with autism were presented with both reinforced training trials and nonreinforced probe trials of models from vocal, toy-play, and pantomime response types. The probe trials were used to examine generalization within each response type. A multiple baseline design was used to analyze percentage of matching and nonmatching responses to models across response types. This study, the first to analyze imitative response classes in children with autism, showed that imitation generalized from reinforced training models to nonreinforced probe models within a response type, but it did not generalize across response types. Thus, functional response classes determined by topographical boundaries were exhibited within generalized imitation.     

The effects of smoked marijuana on progressive-interval schedule performance in humans.

In three experiments, 8 human subjects participated in a study of the effects of smoked marijuana on progressive-interval schedule performance. A two-component chained progressive-interval fixed-interval schedule of point delivery was used. In the progressive-interval component, the interval length began at 20 s and increased either geometrically or arithmetically (by either 20 s, 40 s, 80 s, 100 s, or 160 s) on each subsequent interval. After this interval elapsed, a single button press produced the fixed-interval component, with a total of five reinforcers of varying magnitude ($0.05, $0.20, or $0.40) available on a fixed-interval 20-s schedule. After the five reinforcer deliveries, the schedule returned to the initial progressive-interval component. Several relationships were found among rates of responding, postreinforcement pauses and drug administration in the progressive-interval component: (a) Postreinforcement pauses increased as the temporal requirements of the progressive-interval schedule increased; (b) rates of responding during successive progressive-interval components rapidly decreased to low rates of responding after the first few progressions; (c) postreinforcement pauses decreased systematically as dose of smoked marijuana increased; and (d) rates of responding increased after smoking active marijuana but not after smoking placebo cigarettes. Results are discussed in the context of behavioral control and relevance to other studies that have investigated the effects of smoked marijuana on schedule performance.     

EFFECTS OF SPACED RESPONDING DRL ON THE STEREOTYPED BEHAVIOR OF PROFOUNDLY RETARDED PERSONS

Stereotypic responding and social behaviors of three profoundly retarded children were measured before and during application of a DRL contingency for stereotypic responding. A variant of the standard DRL procedure, spaced responding DRL, was used, in which reinforcement is delivered following a response if that response has been separated from the previous response by at least a fixed minimum time interval. Three children were treated by using a reversal design. Results showed that: (a) during baseline sessions, the children engaged in high rates of stereotypic responding and very low rates of appropriate social behavior; and (b) during DRL sessions, appropriate behavior increased markedly as stereotypic responding was reduced. The data suggest that spaced responding DRL may be effective in increasing appropriate social behavior as well as in reducing stereotypic responding.     

On Finitely-Valued Inference Systems

A proof-theoretical analysis of finite-valuedness in the domain of cumulative inference systems is presented.     

Defining behavioral contrast for multiple schedules

Two different definitions of behavioral contrast have been used for multiple schedules. One, interschedule, definition identifies contrast as changes in the rates of responding which occur when subjects move from one multiple schedule to another. The other, intraschedule, definition emphasizes changes in the rates of responding which occur relative to a baseline rate of responding. The baseline is the rate of responding emitted during a multiple schedule that supplies equal rates of reinforcement in the two components. The distinction between these two definitions is important for empirical and theoretical reasons. For example, theoretical confusion has arisen when the interschedule definition has been used to test and reject theories which implicitly define contrast by the intraschedule definition.     

心理与教育测验中异常反应侦查新技术：变点分析法

变点分析法(change point analysis, CPA)近些年才引入心理与教育测量学, 相较于传统方法, CPA不仅可以侦查异常作答被试, 还能自动精确地定位变点位置, 高效清洗作答数据。其原理在于：判断作答序列中是否存在可将该序列划分为具有不同统计学属性两部分的点(即变点), 并且需使用被试拟合统计量(person-fit statistic, PFS)来量化两个子序列之间的差异。未来可将单变点分析拓展至多变点, 结合反应时等信息, 构建非参数化指标以及将现有指标拓展至多级计分或多维测验, 以提高CPA的适用广度及效力。     

The effects of differential training procedures on linked perceptual class formation

When the stimuli in one perceptual class (A') become related to the stimuli in another perceptual class (B'), the two are functioning as a single linked perceptual class. A common linked perceptual class would be the sounds of a person's voice (class A') and the pictures of that person (class B'). Such classes are ubiquitous in real world settings. We describe the effects of a variety of training procedures on the formation of these classes. The results could account for the development of naturally occurring linked perceptual classes. Two perceptual classes (A' and B') were formed in Experiment 1. The endpoints of the A' class were called anchor (Aa) and boundary (Ab) stimuli. Likewise, the anchor and boundary stimuli in the B' class were represented as Ba and Bb. In Experiment 2, the A' and B' classes were linked by the establishment of one of four cross-class conditional discriminations: Aa-->Ba, Aa-->Bb, Ab-->Ba, or Ab-->Bb. Results were greatest after Aa-->Bb training, intermediate after Aa-->Ba and Ab-->Ba training, and lowest after Ab-->Bb training. Class formation was influenced by the interaction of the anchor/boundary values and the sample/comparison functions of the stimuli used in training. Experiment 3 determined whether class formation was influenced by different sets of two cross-class conditional discriminations: Aa-->Ba and Ab-->Bb, or Aa-->Bb and Ab-->Ba. Both conditions produced equivalent results. Similarities were attributable to the use of anchor stimuli as samples and boundary stimuli as comparisons in each training condition. Finally, the results afterjoint Aa-->Ba and Ab-->Bb training were much greater than those produced by summing the results of Aa-->Ba training alone and Ab-->Bb training alone. This same synergy was not observed after joint Aa-->Bb and Ab-->Ba training or either alone.     

The repeated confrontation with videotapes of spiders in multiple contexts attenuates renewal of fear in spider-anxious students

In a treatment-analogue experiment, extinction of fear of spiders was investigated in a group of spider-anxious students. Two groups were created: in the single extinction group the extinction trials consisted of repeated presentations of a videotaped spider in one specific location of a house, whereas in the multiple extinction group the trials consisted of videotapes of the same spider in three different locations of a house. Also a control group was included that was exposed to videotapes of the location but without the spider. As reflected in skin conductance responses and self-report data, fear of spiders was significantly reduced in the two extinction groups compared to the control group. Moreover, when the extinction groups were confronted with the videotape of the spider in a new location, the single extinction group did not show generalisation of extinction, whereas the multiple extinction group did. These results corroborate the existing evidence for context dependence of extinction of fear and provide new evidence that the use of multiple contexts during extinction might improve the generalisability of extinction in humans. Implications for exposure therapy are discussed.     

The Effects of Using Response Cards on Student Participation, Academic Achievement, and On-Task Behavior During Whole-Class, Math Instruction

This study evaluated the effects of using response cards during whole-group math instruction in a fourth-grade classroom, using an ABA research design. During both A and B conditions the classroom teacher conducted her math lessons as planned. However during the A conditions, hand-raising (HR) was in effect. That is, when the teacher asked a question she instructed the students to raise their hands and after each question she called on one student whose hand was raised. During the B condition, response cards (RC) were in effect. Whenever she asked a question, the teacher instructed the entire class to write their answers on individual response cards. After each question, the teacher instructed the entire class to hold up their RC. Data were collected on five students who represented the class range in general level of participation, academic skills, and on-task behavior. Results indicated that student participation, specifically the number of student-initiated opportunities to respond and the number of student responses were higher when using RC than when HR was in effect. Students scored higher on the weekly math quiz after the RC condition than after the HR conditions. The percentage of intervals that students were on-task also was higher when RC were used.