Contingency Enhances Sensitivity to Loss in a Gambling Task with Diminishing Returns.

This study examined whether gambling behavior under conditions of diminishing returns differed between participants with histories of contingent (CD group) and noncontingent (NCD group) token delivery. In Phase 1, CD participants accrued tokens by correctly completing a discrimination task; for NCD participants, token accrual was yoked to token delivery of CD participants. In Phase 2, participants could choose to gamble their tokens or end the experiment and exchange their tokens for money. During the gambling task, participants could bet one token per trial. The probability of losses began at 10% and increased incrementally across blocks of 10 trials up to 100%. Overall, participants in the CD group gambled on fewer trials than participants in the NCD group. Costs of token accrual during Phase 1, in terms of number of trials and duration, showed a positive correlation with net tokens for the CD group but not the NCD group. Results are consistent with previous research demonstrating the value-enhancing effects of both prior contingent delivery and effort, and offer evidence that these histories influence sensitivity to loss.

Comparing rapid assessments of delay discounting with real and hypothetical rewards in children.

Recent advances in assessment methodology have resulted in a highly efficient procedure for obtaining delay discounting rates for adults: a 5-trial adjusting delay task (ADT-5) examining intertemporal choice for hypothetical rewards. The low participant burden of this task makes it potentially useful for children, with whom delay discounting research is relatively limited. However, it is unknown whether results from this task match choice for real rewards. The present study assessed delay discounting for real and hypothetical monetary rewards using a modified ADT-5 with 9 children admitted to a psychiatric day treatment program. Participants completed up to 3 tasks with each reward type in alternating order. No difference in discounting rate, via log(k), was observed between the first task of each reward type. This finding was replicated across subsequent tasks for the subset of participants (n = 6) who completed all 6 tasks. However, delay discounting of real and hypothetical rewards was not found to be statistically equivalent. These results suggest that a modified ADT-5 using hypothetical rewards may be a viable option for assessing delay discounting in children with psychiatric diagnoses, but additional research is needed to explicitly examine whether hypothetical and real rewards are discounted equivalently in this population.

Erratum to: Effects of mands on instructional control: A laboratory simulation.

[This corrects the article DOI: 10.1007/s40616-014-0015-x.].

Exploring the relationship between preferences for high fat foods and efficacy of the ketogenic and modified Atkins diets among children with seizure disorders.

PURPOSE: Previous research has indicated that children with seizures may prefer high fat foods - a preference compatible with ketogenic and modified Atkins dietary therapies. The purpose of this prospective study was to examine the relationship between fat preference and efficacy of therapeutic diets in treating intractable seizures among a pediatric population. METHODS: Preference for high fat foods was directly assessed in a sample of 30 children prior to commencing either the ketogenic or modified Atkins diet. Seizure control was assessed at 1, 3, 6, and 12 months following diet initiation. Using an intent-to-treat analysis, correlations between fat preference and diet efficacy were examined at each follow-up and across the follow-up period. RESULTS: At individual follow-ups, correlations between fat preference and diet efficacy varied in terms of both strength and significance; however, modest, positive correlations with fat preference were significant when examining high levels of efficacy (100% seizure reduction, ≥90% seizure reduction) across a 1-year follow-up period. CONCLUSION: These findings provide preliminary evidence that fat preference, when directly assessed, may be a useful predictor of treatment efficacy for the ketogenic and modified Atkins diets; however, further research is necessary.

Effects of Mands on Instructional Control: A Laboratory Simulation.

The effects of two types of mands on participants' adherence to instructions were examined across two groups using procedures based on Hackenberg and Joker (Journal of the Experimental Analysis of Behavior 62:367-383, 1994). Participants were presented with instructions describing a pattern of responding for producing points later exchanged for money and were exposed to choice trials in which a progressive-time (PT) and a fixed-time (FT) schedule were concurrently available. The instructions initially described how to optimize point production; however, the PT schedule was manipulated over the course of the experiment such that response patterns maximizing point production differed across conditions. All participants experienced the same experimental arrangement, and the two groups differed only in the form of the mand contained in the instructions presented to them. The instructions for the directive group contained the mand "you must…" (i.e., command) preceding the instructed response pattern, whereas the non-directive group instructions contained the mand "you might consider…" (i.e., suggestion) preceding the instructed response pattern. Results indicated that instruction type influenced response patterns across changing contingencies. The directive group exhibited greater adherence to the instruction than the non-directive group when instruction following was less profitable. Results are interpreted in terms of Skinner's analysis of verbal behavior, and implications for practical application are discussed.

An experimental analysis of negative reinforcement contingencies for adult-delivered reprimands.

Seven adults participated in simulated teaching sessions with an experimenter who role played as a student with developmental disabilities. The experimenter engaged in problem behavior and either (a) terminated problem behavior contingent on participant reprimands (negative reinforcement) or (b) did not terminate problem behavior contingent on reprimands (extinction). Results suggested that reprimands were sensitive to negative reinforcement in the form of the immediate cessation of problem behavior. These preliminary findings support role play as a potentially viable laboratory model for analyzing behaviors of typical adults.