Effects of methylphenidate on sensitivity to reinforcement in children diagnosed with attention deficit hyperactivity disorder: an application of the matching law.
MPH makes kids with ADHD more responsive to reinforcement schedules—track response rates with matching-law analysis to see the change.
01Research in Context
What this study did
Researchers gave kids with ADHD methylphenidate (MPH) while they worked on two levers that paid off at different rates.
The team used the matching law to see if the drug changed how closely the kids’ button presses tracked the real payoff odds.
Each child served as his own control in a single-case lab design.
What they found
On MPH the children pressed faster and their choice pattern fit the matching law more tightly.
In plain words, the drug made the kids better at noticing which lever gave more points and then acting on that difference.
How this fits with other research
Morris et al. (2022) later used the same math to map how autistic children split their time between two play partners.
Together the two papers show the matching law works for both ADHD reinforcement sensitivity and autism sociability.
Older animal work backs the method: DeCarlo (1985) pigeons and Bland et al. (2018) pigeons also followed the matching law under lab schedules, giving confidence that the equation holds across species and settings.
Why it matters
If a child on MPH suddenly looks more “tuned in,” the matching-law slope gives you a number that proves the drug is sharpening reinforcement control, not just slowing hyperactivity.
You can run a five-minute two-choice task, plot the data, and use the fit score to help parents and prescribers see whether the dose is working.
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02At a glance
03Original abstract
The behavior of children diagnosed with attention deficit hyperactivity disorder (ADHD) has been hypothesized to be the result of decreased sensitivity to consequences compared to typical children. The present study examined sensitivity to reinforcement in 2 boys diagnosed with ADHD using the matching law to provide more precise and quantitative measurement of this construct. This experiment also evaluated the effects of methylphenidate (MPH) on sensitivity to reinforcement of children with ADHD. Subjects completed math problems to earn tokens under four different variable-interval (VI) schedules of reinforcement presented in random order under both medicated and nonmedicated conditions. Results showed that, in the medicated condition, the matching functions for both subjects resulted in higher asymptotic values, indicating an overall elevation of behavior rate under these conditions. The variance accounted for by the matching law was also higher under the medicated conditions, suggesting that their behavior more closely tracked the changing rates of reinforcement while taking MPH compared to placebo. Under medicated conditions, the reinforcing efficacy of response-contingent tokens decreased. Results are discussed with respect to quantifying behavioral changes and the extent to which the drug interacts with prevailing contingencies (i.e., schedule values) to influence behavioral variability.
Journal of applied behavior analysis, 2000 · doi:10.1901/jaba.2000.33-573