Biomedical subjects

Mark R Dixon

Publications and source records attributed to Mark R Dixon.

10 recordsLinked to original sources

PubMed2006

Modification of slot-machine preferences through the use of a conditional discrimination paradigm.

The present experiment investigated the impact of contextually trained discriminations on gambling behavior. Nine recreational slot-machine players were initially exposed to concurrently available computerized slot machines that were each programmed on random-ratio schedules of reinforcement and differed only in color. All participants distributed responding equally across the two slot machines. A conditional discrimination procedure was then used to teach the contextual cues representing the arbitrary relations of "greater than" and "less than." Following contextual cue training, participants were reexposed to the concurrent slot-machine task. After training of the contextual cues, a higher proportion of responses were made to the slot machine that shared formal properties (i.e., color) with the contextual cue representing "greater than."

Choice Behavior↗

PubMed2006

An evaluation of response allocations to concurrently available slot machine simulations.

Gambling behavior often involves making choices between concurrently available game options. With regard to slot machine gambling, multiple games allow for choices to be made with respect to which game to play. The authors of the present study used a slot machine simulation created in Visual Basic.NET to examine gambling preference. The specific question addressed was whether gamblers prefer a smaller payout more often (averaging around every 10 spins) over a larger payout less often (averaging around every 50 spins). Two types of reinforcement were examined during the study: frequency of payouts and the amount of credits won. The results indicate that participants had a preference for a slot machine with the more frequent payout as opposed to one with more intermittent payout. These results support existing literature on theories of choice and provide a step toward understanding human gambling behavior.

Computer Simulation↗

PubMed2005

Evaluating the establishment and maintenance of visual-visual and gustatory-visual equivalence relations in adults with developmental disabilities.

Four adults with developmental disabilities were taught to make conditional discriminations between either pictures and their corresponding printed English and Spanish words, or tastes and their corresponding printed English and Spanish words. Participants required more training trials to master the visual-visual conditional discriminations than the gustatory-visual conditional discriminations, and 3 of the 4 participants performed with higher accuracy on visual equivalence class test trials than gustatory-visual equivalence class test trials. A follow-up equivalence test conducted 30 to 40 days later showed substantially greater stability over time for the gustatory-visual classes than for the visual classes, for all participants. That participants acquired gustatory-visual conditional discriminations, as well as equivalence classes based on those conditional discriminations, may have relevance for incorporating gustatory stimuli into mand training sessions, as well as for teaching individuals with sensory impairments in other modalities.

Adult↗

PubMed2004

Preference for progressive delays and concurrent physical therapy exercise in an adult with acquired brain injury.

The purpose of this study was to increase self-control and engagement in a physical therapy task (head holding) for a man with acquired traumatic brain injury. Once impulsivity was observed (i.e., repeated impulsive choices), an experimental condition was introduced that consisted of choices between a small immediate reinforcer, a large fixed-delay reinforcer, and a large progressive-delay reinforcer. The participant showed a preference for the progressive-delay option, even when the duration of the delay exceeded that of the fixed delay. The results have implications for establishing optimal choice making and teaching life-enhancing skills.

Adult↗

PubMed2004

A computerized simulation for investigating gambling behavior during roulette play.

The present paper describes a computerized roulette program for the conducting of psychological research on gambling behavior. The program was designed to simulate an actual roulette game found in casinos and gambling riverboats throughout North America. The roulette program collects detailed trial-by-trial data on player/participant behavior that can easily be transferred into data analysis and graphics programs. This multimedia simulation was designed in the Visual Basic programming language, and it is capable of running on any IBM-compatible personal computer running the Windows 2000 or higher operating system.

Computer Simulation↗

PubMed2003

Enhancing tolerance to delayed reinforcers: the role of intervening activities.

Three participants with moderate to profound mental retardation were exposed to choices between an immediate small amount and a delayed larger amount of a preferred reinforcer. All participants initially showed a relatively high preference for the smaller reinforcer, suggesting impulsive choice making. However this preference reversed, suggesting self-control, when the larger reinforcer was available immediately and, over time, its delay was gradually increased. Results highlight the potential utility of incorporating concurrent activities into self-control training paradigms.

Adaptation, Psychological↗

PubMed2003

Creating a portable data-collection system with Microsoft Embedded Visual Tools for the Pocket PC.

This paper describes an overview and illustrative example for creating a portable data-collection system using Microsoft Embedded Visual Tools for the Pocket PC. A description of the Visual Basic programming language is given, along with examples of computer code procedures for developing data-collection software. Program specifications, strategies for customizing the collection system, and troubleshooting tips are also provided.

Behavior Therapy↗

PubMed2003

Self-control and the preference for delayed reinforcement an example in brain injury.

We investigated the effects of a concurrent physical therapy activity (keeping the hand open) during delays to reinforcement in an adult man with acquired brain injuries. Once a relatively stable level of hand-open behavior was obtained, the participant was asked to choose between a small immediate reinforcer and a larger delayed reinforcer contingent on keeping the hand open at greater-than-baseline duration. Afterwards, the participant was asked to select between a larger delayed reinforcer with no hand-open requirement and the identical larger delayed reinforcer with a progressively increasing hand-open requirement. Results suggest a shift in preference to larger delayed reinforcers and an eventual preference for the hand-open requirement option.

Adult↗

PubMed2003

Delay discounting by pathological gamblers.

Discounting of delayed rewards by pathological gamblers was compared to discounting of delayed rewards by matched control nongambling participants. All participants completed a hypothetical choice task in which they made repeated choices between dollars 1,000 available after a delay and an equal or lesser amount of money available immediately. The delay to the large amount of money was varied from 1 week to 10 years across conditions. Indifference points between immediate money and delayed money were identified at each delay condition by varying the amount of immediate money across choice trials. For the majority of participants, indifference points decreased monotonically across delays. Overall, gamblers discounted the delayed rewards more steeply than did control participants.

Adult↗

PubMed2003

Attendance probabilities of participants in a human experiment.

This study investigated how different prompting strategies affected the attendance probabilities of 60 undergraduate students participating in an experiment. Subjects were randomly assigned to one of three conditions: no prompt, phone-message prompt, or phone-voice prompt. Analysis showed that participants in the no-prompt condition attended the study at a rate of 50%. Participants who received a phone-message prompt attended at a rate of 55%, while participants who received a phone-voice prompt attended at a rate of 100%.

Humans↗