Dr. Christine Hughes, Graduate Coordinator & Professor
I have several lines of behavior-analytic research in which students participate. Currently, my research involves the experimental analysis of behavior in rats and pigeons in areas of translational science.
Aversive Aspects of Positive Reinforcement. Although completing work can be reinforced by finishing the task and receiving compensation for doing so, the work itself can be aversive. Indeed, we often delay doing work even though we know it has to be done. Signals, prompts, or reminders of the work that has to be done can in turn become aversive and might disrupt ongoing behavior when they are presented. Transitioning from periods of leisure or less work to periods of more work, which are signaled, occur in many contexts and also can be aversive. For example, a child must transition from recess back inside to class when the teacher announces the end of recess, a worker must transition from the weekend to Monday morning back at work, etc. During these transitions, aberrant behavior (e.g., aggression, escape, self-injury) might occur. The function of signals or prompts to complete work is not fully understood and is under-researched. In a series of experiments, we have been examining the effects of signals of upcoming work and of different transitions on ongoing behavior of pigeons that is maintained by food presentation.
Punishment: Timeout from Positive Reinforcement. Although timeout often is used in homes and schools to decrease unwanted behavior, there is still the need for research on variables that alter timeout's effectiveness. Currently, we are examining the effects of different timeout durations on behavior maintained by different rates of reinforcement. I also am interested in effects of different types of timeouts, how timeout affects other unpunished behaviors, and how other reinforcement variables (e.g., deprivation) alter timeout's effects. Future research will extend these variables to the examination of response cost. Given that many children are taking prescription medications, such as Ritalin, and experience timeout, I also am interested in effects of drugs on behavior punished by timeout and/or response cost.
Drugs and Impulsivity. Drugs of abuse can affect decision making. Stimulant drugs (e.g., amphetamine) often decrease "impulsive" choices, that is, instead of choosing an immediate, but small reinforcer ("impulsivity"), subjects tend to choose a delayed but larger reinforcer ("self-control") more often. Other drugs tend to increase impulsive choices. In our lab, we investigate both acute and chronic effects of drugs such as methylphenidate (i.e., Ritalin), amphetamine, morphine, and oxycodone on impulsive choices. In addition, we examine effects of drug withdrawal on impulsive behavior and how components of impulsive choices - reinforcement delay and magnitude - contribute to the drugs' effects.
Recent Publications (student co-authors indicated by *)
*Retzlaff, B. J., *Parthum, E. T. P., Pitts, R. C., & Hughes, C. E. (accepted). Escape from rich-to-lean transitions: Stimulus change and timeout. Journal of the Experimental Analysis of Behavior
Pitts, R. C., *Cummings, C. W., *Cummings, C., & Hughes, C. E. (2016). Methylphenidate and impulsive choice: Potential roles of sensitivity to reinforcement delay and sensitivity to reinforcement amount. Experimental and Clinical Psychopharmacology, 24.
Aparicio, C. F., Baum, W. M., Hughes, C. E., & Pitts, R. C. (2016). Limits to preference and the sensitivity of choice to rate and amount of food. Journal of the Experimental Analysis of Behavior, 105, 322-337.
*Smith, T. T., McLean, A. P., Shull, R. L., Hughes, C. E., & Pitts, R. C. (2014). Concurrent performance as bouts of behavior, Journal of the Experimental Analysis of Behavior, 102,102-125.
McLean, A. P., Grace, R. C., Pitts, R. C., & Hughes, C. E. (2014). Preference pulses without reinforcers. Journal of the Experimental Analysis of Behavior, 101, 317-336.
Aparicio, C. F., Hughes, C. E., & Pitts, R. C. (2013). Impulsive choice in Lewis and Fischer 344 rats: Effects of extended training. Conductual, International Journal of Interbehaviorism and Behavior Analysis, 1(3), 22-46.
*Rodewald, A. M., Hughes, C. E., & Pitts, R. C. (2010). Choice in a variable environment: Effects of d-amphetamine on sensitivity to reinforcement. Behavioural Processes, 84, 460-464.
*Maguire, D. R., *Rodewald, A. M., Hughes, C. E., & Pitts, R. C. (2009). Rapid-acquisition of preference in concurrent schedules: Effects of d-amphetamine on sensitivity to reinforcement amount. Behavioural Processes, 81, 238-243.
*TA, W. -M., Pitts, R. C., Hughes, C. E., McLean, A. P., & Grace, R. C. (2008). Rapid acquisition of preference in concurrent chains: Effects of d-amphetamine on sensitivity to reinforcement delay. Journal of the Experimental Analysis of Behavior, 80, 71-91.