EFFECTS OF REWARD AND RESPONSE COSTS ON INHIBITION IN ADHD CHILDREN

This study examined effects of reward and response costs on the abilit y of 19 attention-deficit hyperactivity disorder (ADHD) and 17 control children to inhibit responding. Children were tested under 4 reinforc ement conditions on a go/no-go learning task developed by J.P. Newman, C.S. Widom, and S. Nathan (1985). Two conditions involved both reward and response costs, 1 response costs only, and 1 reward only. ADHD ch ildren made more commission errors than controls across the 4 conditio ns. Analyses of learning curves indicated that group differences becam e larger on later trials. Thus, impaired inhibition was more generaliz ed in ADHD children than in the psychopaths and extraverts studied by Newman and colleagues, and it became most evident when the children we re required to improve learning across trials.