Infrequent, but not frequent, reinforcers produce more variable responding and deficient sustained attention in young children with attention-deficit/hyperactivity disorder (ADHD)
Article first published online: 9 JUN 2005
Journal of Child Psychology and Psychiatry
Volume 47, Issue 5, pages 457–471, May 2006
How to Cite
Aase, H. and Sagvolden, T. (2006), Infrequent, but not frequent, reinforcers produce more variable responding and deficient sustained attention in young children with attention-deficit/hyperactivity disorder (ADHD). Journal of Child Psychology and Psychiatry, 47: 457–471. doi: 10.1111/j.1469-7610.2005.01468.x
- Issue published online: 9 JUN 2005
- Article first published online: 9 JUN 2005
- Manuscript accepted 13 January 2005
- Hyperkinetic disorder;
- computer task;
- operant analysis
Background: The underlying behavioral/psychological processes of attention-deficit/hyperactivity disorder are unclear. Motivational factors, related to dopamine dysfunction, may play an important role in the development of the behavioral symptoms. Particularly, infrequent, but not frequent, reinforcers have been suggested to be associated with altered responding and deviant behavior in children with ADHD. The present study was designed to analyze the influence of reinforcement frequency on operationalized measures of hyperactivity, impulsiveness, sustained attention, and response variability.
Methods: Fifty-six boys, half of whom were diagnosed with ADHD, completed a computerized task presented as a game with two squares on the screen. One square was associated with reinforcement. The task required responses by the computer mouse under contingencies alternating between variable interval schedules of short (mean 2 s) and long (mean 20 s) durations. Reinforcers were cartoon pictures and small trinkets.
Results: Overall, there was no difference between children with ADHD and comparison children when reinforcers were given frequently. Statistically significant differences on measures of sustained attention and variability, but not hyperactivity and impulsiveness, were found during infrequent reinforcement only. Age effects interacted with group effects on sustained attention, showing that group differences were found in the young children only. Surprisingly, older comparison children showed increased response variability and no learning.
Conclusions: When reinforcers are infrequent, children with ADHD show deficient sustained attention and increased variability in responding. Computer experience may have interfered with measures of hyperactivity and impulsiveness. The unexpectedly poor performance of the older comparison children may have been due to inefficient reinforcers or to verbally governed behavior overruling reinforcer effects. Reinforcer characteristics and experimental procedures are important factors influencing findings in studies investigating motivational factors. The study provides some support for the dynamic developmental theory of ADHD predicting relationships between neurobiological deficits, altered reinforcement mechanisms, and treatment recommendations.