Equivalence class formation in language-able and language-disabled children

Stimulus equivalence seems to have relevance to the study of semantics and of language more generally. If so, there may be a relation between language use and the demonstration of stimulus equivalence. This was examined in three groups of children ranging in chronological age and matched on a conventional measure of mental age: normally developing preschoolers, retarded children who used speech or signs spontaneously and appropriately, and retarded children who did not. All children were taught a series of four related discriminations and were then tested to determine if classes of equivalent stimuli had formed. All of the language-able children (retarded and normal) formed equivalence classes, whereas none of the language-disabled children did so. Although the exact nature of the relation between stimulus equivalence and language remains to be clarified, these results support the view that stimulus equivalence is a phenomenon with relevance to language.     

A SCATTER PLOT FOR IDENTIFYING STIMULUS CONTROL OF PROBLEM BEHAVIOR

Line graphs that average response frequency over long periods obscure the major rate changes that indicate sources of behavioral control. A scatter plot can make patterns of responding identifiable and, in turn, suggest environmental features that occasion undesirable behavior. Use of scatter diagrams is illustrated in three cases.     

TEACHING BETWEEN-CLASS generalization OF TOY PLAY BEHAVIOR TO HANDICAPPED CHILDREN

In this study, young children with severe and moderate handicaps were taught to generalize play responses. A multiple baseline across responses design, replicated with four children, was used to assessthe effects of generalization training within four sets of toys on generalization to untrained toys from four other sets. The responses taught were unique for each set of toys. Acrossthe four participants, training to generalize within-toy sets resulted in complete between-class generalization in 11 sets, partial generalization in 3 sets, and no generalization in 2 sets. No generalization occurred to another class of toys that differed fromthe previous sets in that they produced a reaction tothe play movement (e.g., pianos). Implications for conducting research using strategies based on class interrelationships in training contexts are discussed.     

Promoting safety belt use among state employees: the effects of prompting and a stimulus-control intervention.

This study assessed the effects of dashboard stickers and signature sheets on safety belt use among occupants of state-owned vehicles in three Florida agencies. The stickers and signature sheets contained information regarding a regulation requiring safety belt use and a consequence of a 25% reduction in benefits for noncompliance if the driver were to become involved in an accident. Safety belt use significantly increased during the intervention phase in all three agencies and maintained variable but high levels for 5 months. In Agency 1 and Agency 2 (stickers plus signature sheets) safety belt use increased from averages of 10.8% and 9.4% during baseline to 57.4% and 47.0%, respectively, during intervention. In Agency 3 (stickers only) the rates of safety belt use averaged 9.7% during baseline and 38.0% during intervention. Some increases in private vehicle use were observed. A substantial reduction in workers'' compensation claim costs was shown for the target agencies with some reductions also shown in the nontarget agencies.     

Behavioral stereotypy and the generalized matching equation

The development of behavioral stereotypy is a common result of exposure to both response-dependent and response-independent reinforcement procedures. The generalized matching equation and two dynamic versions of that equation, which take into account the time differential between reinforcements and their effect on behavior, predict this outcome of many procedures involving reinforcement. Following from the assumption that distinct response topographies, distinct response sequences, or orientations to distinct stimuli can be treated in the equations as distinct classes of behavior, the equations predict that-at least for matching and undermatching-the behavior class that is most biased relative to other behavior classes of the same type will tend to predominate to the exclusion or near exclusion of those behavior classes.     

Use of an ambiguous-sample procedure to establish a cue to forget in pigeons

Pigeons were trained on a variation of the matching-to-sample task in which on double-sample trials two samples, one associated with each of the comparison stimuli, were presented successively. Responding to the comparison associated with the first sample was reinforced on half the double-sample trials, and responding to the comparison associated with the second sample was reinforced on the remaining half. One of two postsample stimuli was presented following the termination of each colored sample. A vertical line was presented after a correct or target sample, and a horizontal line was presented after an incorrect or interfering sample. With extended training, each bird demonstrated above-chance accuracy on double-sample trials, providing prima facie evidence that one or both of the postsample stimuli exerted control over matching behavior. Experiment 2 provided evidence that the horizontal line functioned as a cue to forget the code activated by the preceding sample stimulus. It was concluded that a condition sufficient to establish a postsample stimulus as a cue to forget is that the postsample immediately follow presentation of a sample that, if it were to control test responding, would lead to nonreinforcement.     

Comparison of Different Feedback Procedures in Second Language Vocabulary Learning

Research into the learning of Second Language (SL) vocabulary by beginning learners has indicated that the simultaneous presentation of the First and Second Language words results in blocking of the learning process by the familiar First Language (FL) word. Previous research also suggests that blocking by the First Language can be eliminated by bringing it in as informative feedback (either as a written or spoken word). Our experiments were designed to further extend this research. The use of a picture, either as feedback or simultaneously presented with its equivalent, along with the aural feedback and the conventional procedures were investigated in Experiment 1. Results revealed that pictures blocked the learning process less than the written FL word when both were presented with their SL referent. When used as feedback, however, pictures were not as good as the spoken FL word. Experiment 2 demonstrated that aural feedback was the best type of feedback when compared with the picture and written FL presentations, and that the picture feedback was better than the written feedback. Taken together, the results of these two studies showed that all forms of feedback overcame the problem of blocking created by simultaneous presentation of the FL and SL words, and that aural feedback was the most effective feedback procedure. It was suggested that the superiority of aural feedback was likely to be a consequence of the use of a different input channel to that of the visually presented written SL word.     

The effects of varying the distribution of generalization stimuli within a constant range upon the bisection of a sound-intensity interval by rats

Two male, albino rats were trained on a two-valued, self-paced, discrete-trials auditory discrimination. In the presence of a high-intensity stimulus (90 decibels SPL, 4 kiloHertz), response A was reinforced; in the presence of a low-intensity stimulus (50 decibels SPL, 4 kiloHertz), response B was reinforced. When discrimination performance was asymptotic, stimuli intermediate in intensity were presented with the training stimuli in a maintained generalization paradigm. Generalization gradients were derived from the relative frequencies of response A in the presence of each stimulus. A relative frequency of 0.50 was then determined and used as the bisection point of the intensity interval defined by the 90- and 50-decibel stimuli. The bisection point varied with the distribution of the stimuli presented in generalization. This effect was similar to context effects seen in human psychophysics.     

Conjunctive schedules of response-dependent and response-independent reinforcement

Pigeons received food when they emitted the number of responses specified by a fixed-ratio schedule, and the time specified by a fixed-time schedule had elapsed. The order of meeting the response and time requirements was irrelevant. In different conditions, stimuli signalled completion of one, both, or neither requirement. Ratio size interacted with stimulus condition to determine performance. When a stimulus signalled the end of the fixed-time period, under all ratios the birds tended to respond after the stimulus appeared. When stimuli followed both components, small ratios produced responding during the fixed-time period, and other ratios resulted in responses after the time period had elapsed. With either no stimulus changes, or with a stimulus correlated with completion of the ratio alone, responding first increased and then decreased as the ratio increased. Low and high ratios produced stable response frequencies and patterns in successive intervals. Intermediate ratios resulted in two types of performance. Intervals with long initial pauses and few responses during the fixed-time period were followed by intervals with short pauses and numerous responses and vice versa. The source of these dynamic effects was hypothesized to be number of responses per reinforcer in one condition and response-reinforcer contiguity in the other.