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Altered reinforcement mechanisms in attention-deficit/hyperactivity disorder
T Sagvolden1, H Aase, P Zeiner
1Department of Neurophysiology, University of Oslo, Norway.
Behavioural Brain Research
|August 26, 1998
Summary
Children with attention-deficit/hyperactivity disorder (ADHD) exhibit impulsiveness and sustained-attention deficits. These behaviors are linked to a steeper and shorter delay-of-reinforcement gradient compared to neurotypical children.
Area of Science:
- Neuroscience
- Child Psychology
Background:
- Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder.
- Impulsiveness and sustained attention deficits are key behavioral characteristics of ADHD.
Purpose of the Study:
- To investigate if ADHD is associated with a steeper and shorter delay-of-reinforcement gradient.
- To examine the behavioral differences between children with ADHD and a comparison group during a reinforcement schedule task.
Main Methods:
- A two-component reinforcement schedule was employed with 8 boys diagnosed with ADHD and 12 neurotypical boys (aged 7-12).
- One component utilized a 30-s fixed interval (FI) schedule, while the other was an extinction (EXT) component.
- Reinforcers (trinkets or coins) were delivered in a game-like setting.
Main Results:
- Children with ADHD displayed hyperactivity, characterized by response bursts with short interresponse times (IRTs) during both FI and EXT components.
- ADHD children exhibited a sustained-attention deficit, resuming responding during extinction as if reinforcement were still available.
- The comparison group ceased responding during extinction and did not exhibit impulsiveness.
Conclusions:
- Findings support the hypothesis that ADHD is associated with a steeper and shorter delay-of-reinforcement gradient.
- The observed response bursts in ADHD children may represent impulsiveness, a core ADHD trait.
- Behavior during extinction suggests a deficit in sustained attention in children with ADHD.