Applications of computer-based instruction: using specialized software to aid letter-name and letter-sound recognition

We evaluated computerized training and testing programs with children who were having difficulties learning prereading skills. The programs were derived from equivalence research and were written in authoring software designed for educators. After learning to match uppercase and lowercase printed letters to the corresponding letter names (Tasks 1 and 2), the children matched the letters to one another (Tasks 4 and 5). Then, after learning to match uppercase letters to sounds (Task 3), they also matched lowercase letters to sounds (Task 6) and matched printed to spoken words (Tasks 7 and 8). The results recommend equivalence-based protocols and user-friendly software in further development of prereading instruction.     

Noncontingent reinforcement, alternative reinforcement, and the matching law: a laboratory demonstration

Basic researchers, but not most applied researchers, have assumed that the behavior-decelerating effects of noncontingent reinforcement result at least partly from adventitious reinforcement of competing behaviors. The literature contains only sketchy evidence of these effects because few noncontingent reinforcement studies measure alternative behaviors. A laboratory model is presented in which concurrent schedules of contingent reinforcement were used to establish a "target" and an "alternative" behavior. Imposing noncontingent reinforcement decreased target behavior rates and increased alternative behavior rates, outcomes that were well described by the standard quantitative account of alternative reinforcement, the generalized matching law. These results suggest that adventitious reinforcement of alternative behaviors can occur during noncontingent reinforcement interventions, although the range of conditions under which this occurs remains to be determined in future studies. As an adjunct to applied studies, laboratory models permit easy measurement of alternative behaviors and parametric manipulations needed to answer many research questions.     

Effects of anorectic drugs on food intake under progressive-ratio and free-access conditions in rats

The effects of two anorectic drugs, dexfenfluramine and phentermine, on food intake under different food-access conditions were examined. Experiment 1 compared the effects of these drugs on food intake under a progressive-ratio (PR) schedule and free-access conditions. Dexfenfluramine decreased food intake under both conditions, but the doses required to decrease intake under free-access conditions were higher than those required to reduce intake under the PR condition. Intermediate doses of phentermine sometimes increased breaking points, and higher doses decreased them. Phentermine decreased food intake at the same doses under both access conditions. Thus the potency of dexfenfluramine, but not phentermine, to decrease food-maintained behavior depended upon the food-access condition. Experiment 2 used a novel mixed progressive-ratio schedule of food delivery to study the duration of drug effects. Sessions consisted of five components separated by 3-hr timeouts. The ratio requirement reset at the beginning of each component and a new breaking point was obtained. Both dexfenfluramine and phentermine dose-dependently decreased breaking points early in the session. In some rats, compensatory increases in breaking point were observed. That is, breaking points later in the session increased over control levels, resulting in no change in the total number of food pellets earned for the session compared to control. The present findings suggest that the effects of some anorectic drugs depend upon the access conditions for food; increasing the effort to obtain food may enhance their ability to decrease food-maintained behavior.     

A rapid assessment of skills in young children with autism

Educational interventions based on the principles of behavior analysis are highly effective for establishing skills in young children with autism. As a first step in program development, the child's current skill level is determined by evaluating performance on tasks drawn from a preestablished curriculum. However, few specific guidelines have been delineated for conducting these skills assessments or interpreting the results. In this study, we evaluated an efficient methodology for conducting skills assessments. Six children who had been diagnosed with autism participated. The relative efficacy of two assessment packages--one containing several reinforcement procedures and one containing several potentially effective prompts--was evaluated across two to three skills for each child using multiple baseline and reversal designs. Results suggested that the methodology was useful for matching targeted skills to appropriate interventions.     

Systematic application and removal of protective equipment in the assessment of multiple topographies of self-injury

We evaluated the effects of systematic application and removal of protective equipment on three topographies of self-injurious behavior (SIB) exhibited by a girl who had been diagnosed with autism. Results showed that when protective equipment was applied, SIB decreased to near-zero levels. In addition, withdrawal of protective equipment for specific topographies of SIB (by removing only the corresponding padding) increased rates of SIB only for that topography of SIB. Next, a functional analysis of hand SIB showed that protective equipment suppressed this behavior in all conditions and that the behavior was maintained by automatic reinforcement when padding was removed. Results are discussed in terms of sensory extinction as a possible mechanism responsible for response suppression.     

Disposition to recognize goals in infant chimpanzees

Do nonhuman primates attribute goals to others? Traditional studies with chimpanzees provide equivocal evidence for “mind reading” in nonhuman primates. Here we adopt looking time, a methodology commonly used with human infants to test infant chimpanzees. In this experiment, four infant chimpanzees saw computer-generated stimuli that mimicked a goal-directed behavior. The baby chimps performed as well as human infants, namely, they were sensitive to the trajectories of the objects, thus suggesting that chimpanzees may be endowed with a disposition to understand goal-directed behaviors. The theoretical implications of these results are discussed.     

Six-year-olds' difficulties handling intensional contexts

Previous research shows that children have difficulties handling intensional contexts even when they can pass a test of false belief (e.g. Cognition 67 (1998) 287; Cognition 25 (1987) 289). Some authors (Perner, J. (1991). Understanding the representational mind. Cambridge, MA: MIT Press; Cognition 25 (1987) 289) place these difficulties in the linguistic and not the mental representational domain. The experiments reported here examined whether 6-year-old children could answer questions in an intensional context that did not require the explicit verbal characterization of a belief. We replicated previous findings and found that children answered according to their own knowledge in an intensional context. This occurred even though they responded by choosing a picture to insert into a protagonist's thought bubble rather than report the belief verbally. Children could correctly answer questions about the knowledge state of the protagonist and pass a test of false belief. Further experiments ruled out methodological explanations. Experiment 2 showed that the difference in answering according to own knowledge between the false belief and intensional stories is not accounted for by procedural factors in the two types of test. Experiment 3 revealed that children did not answer according to their own knowledge by default. Experiment 4 suggested that answering according to own knowledge was not a result of pictorial salience. Results are discussed in relation to the simulation-theory debate.     

Using video modeling and reinforcement to teach perspective-taking skills to children with autism

We evaluated video modeling and reinforcement for teaching perspective-taking skills to 3 children with autism using a multiple baseline design. Video modeling and reinforcement were effective; however, only 2 children were able to pass an untrained task, indicating limited generalization. The findings suggest that video modeling may be an effective technology for teaching perspective taking if researchers can continue to develop strategies for enhancing the generalization of these new skills.