Excitatory second-order conditioning using a backward first-order conditioned stimulus: A challenge for prediction error reduction.

Prével and colleagues reported excitatory learning with a backward conditioned stimulus (CS) in a conditioned reinforcement preparation. Their results add to existing evidence of backward CSs sometimes being excitatory and were viewed as challenging the view that learning is driven by prediction error reduction, which assumes that only predictive (i.e., forward) relationships are learned. The results instead were consistent with the assumptions of both Miller's Temporal Coding Hypothesis and Wagner's Sometimes Opponent Processes (SOP) model. The present experiment extended the conditioned reinforcement preparation developed by Prével et al. to a backward second-order conditioning preparation, with the aim of discriminating between these two accounts. We tested whether a second-order CS can serve as an effective conditioned reinforcer, even when the first-order CS with which it was paired is a backward CS that elicits no responding. Evidence of conditioned reinforcement was found, despite no conditioned response (CR) being elicited by the first-order backward CS. The evidence of second-order conditioning in the absence of excitatory conditioning to the first-order CS is interpreted as a challenge to SOP. In contrast, the present results are consistent with the Temporal Coding Hypothesis and constitute a conceptual replication in humans of previous reports of excitatory second-order conditioning in rodents with a backward CS. The proposal is made that learning is driven by "discrepancy" with prior experience as opposed to " prediction error."

Role of spatial contiguity in sensory preconditioning with humans.

The present study demonstrates the contribution of spatial contiguity in the formation of associations between two neutral stimuli. Using human participants, we used visual conditioned stimuli (CSs) in a sensory preconditioning design in which simultaneous CS2-CS1 pairings and CS4-CS3 pairings were interspersed during Phase 1, followed by sequential CS1-US+ (i.e., CS1-pleasant US) and CS3-US-- (i.e., CS3-unpleasant US) pairings during Phase 2. The conditioned response was a shift in the gaze of the participants to the location where the US+ (i.e., short video clip) appeared. Distances between CS2 and CS1 and between CS4 and CS3 were manipulated. Our results showed a greater response to CS2 when the Phase 1 stimuli were adjacent rather than separated by 100 pixels. Implications for the role of spatial contiguity in associative learning are discussed.

Timeout from a high-force requirement as a reinforcer: an effective procedure for human operant research.

A procedure to study human operant conditioning is described using a timeout from a high-force requirement as reinforcer when a high force response was required. Experiment 1 reported evidence that a timeout from a high-force requirement acted as a reinforcer and a second experiment demonstrated sensitivity to delay to escape from the force requirement as a parameter of choice in a self-control paradigm. The results of the two experiments indicate a functional similarity between unconditioned reinforcers (e.g., food) used in nonhuman subjects and the present reinforcer, demonstrating that the present procedure is well-suited to study operant conditioning in humans.

Increasing compliance with medical examination requests directed to children with autism: effects of a high-probability request procedure.

The purpose of this study was to evaluate the effectiveness of a high-probability (high-p) request sequence as a means of increasing compliance with medical examination tasks. Participants were children who had been diagnosed with autism and who exhibited noncompliance during general medical examinations. The inclusion of the high-p request sequence effectively increased compliance with medical examination tasks. In addition, the procedure was efficient, could be implemented by parents and medical professionals, and did not involve aversive procedures.

A controlled single-case treatment of severe long-term selective mutism in a child with mental retardation.

The aim of the present study was to demonstrate the efficacy of combining two operant learning procedures--shaping and fading--for treating selective mutism. The participant was a 12-year-old boy with mental retardation presenting a severe long-term selective mutism. The treatment was aimed at increasing the loudness of his vocalizations in an increasingly social milieu. The treatment was conducted over the course of about 20 weeks, with four 15-minute sessions per week. A gradual increase in speech loudness was observed. Data indicated a close correspondence between the changes in speech loudness and the criteria for reinforcement successively applied by the therapist, thereby confirming the causal link between the child's progress and the changes in reinforcement contingencies. In addition, good generalization was noted during the stimulus fading phase. Six-month follow up showed that loudness of verbalizations was still satisfactory in the classroom despite a change of school and peer group. The impressive improvement of the child's verbal behavior shows that the implementation of a treatment package including both shaping and stimulus fading is a worthwhile therapeutic option, even in the case of severe long-term selective mutism associated with mental retardation.

The reinforcing effect of contingent attention on verbal perseverations of two children with severe visual impairment.

The frequency of verbal perseverations of two children with severe visual impairment was reduced using differential reinforcement of appropriate speech coupled with extinction of perseverative utterances. A reversal design in which baseline and intervention were alternated in an A-B-A-B sequence was employed to show the functional relationship between the target behaviors and the treatment procedure. There was a marked increase in appropriate utterances and a correlated decrease in perseverative ones. These findings suggest that this singular feature of the language of certain children with visual impairment is, under natural conditions, probably maintained by the attention provided by their caregivers.