Together these studies might indicate whether similar traits across disorders link to similar patterns of sensitivity to reward and punishment, or whether differences in such sensitivity is commonly related to the phenomenology of the symptoms of each disorder.
Tripp and Alsop (1999) found rewards in a signal-detection task had different influences on the performance of boys with ADHD than boys without ADHD. Once the boys without ADHD (control) created a pattern of response bias towards the option that was more frequently rewarded, they continued to follow this pattern even when there were sometimes local changes in the reward frequencies. In contrast, the boys with ADHD did not establish a stable pattern of response bias. They tended to show shifts in their response bias to rewards based on local changes in reward frequency. They had more difficulty remaining on task and tended to act more impulsively than controls in an attempt to acquire some sort of immediate satisfaction. This supports the notion that the behaviour of individuals with ADHD is likely to be reinforced via immediate reinforcers more so than history of reinforcement, as well as needing large amounts of instant reinforcers to more effectively encourage on-task behaviours in these individuals (Tripp & Alsop,