Behavioral and emotional responding to reinforcement and punishment in children with ADHD: improving our understanding of the condition

Several theoretical accounts propose altered motivational processing to underly ADHD symptoms and propose emotional responding to play a role herein. However, empirical evidence is limited. The main goal of this dissertation was to increase our understanding of the behavioral and emotional responding of children with ADHD to reinforcement and punishment. The first aim was to conduct a systematic review of the experimental evidence on instrumental learning in ADHD. The second aim was to add to the limited evidence by conducting two studies on instrumental learning in ADHD using different reinforcement schedules, whilst also assessing emotional responding to these schedules in one of these studies. The last aim was to examine both behavioral and emotional responding to punishment, and the potential interaction between the two. 

In chapter one, the theoretical accounts assuming altered motivational processing in ADHD are outlined and current experimental evidence related to the theories’ predictions is described. 

Chapter two describes the systematic review on instrumental learning deficits in children with ADHD, showing very few and highly heterogenous studies with methodological limitations and inconsistent findings. Chapter three reports an experimental study on the effects of reinforcement schedule on instrumental learning in children with ADHD, showing clear instrumental learning deficits in children with ADHD across both continuous and partial (20%) reinforcement, and faster extinction after partial reinforcement. In chapter four, both the behavioral performance and the emotional responding of children with ADHD to different reinforcement schedules is investigated. The findings of slower learning under continuous and partial reinforcement were not replicated when a denser reinforcement schedule (33%) was used and the reduced behavioral persistence after partial reinforcement was not found. However, children with ADHD did show more negative emotional expressions during both learning and extinction, irrespective of reinforcement schedule. Chapter five reports a study regarding the behavioral and emotional responding of children with ADHD to punishment, showing both children with and without ADHD acted to avoid punishment with no group differences. Children with ADHD did however show more positive and negative emotional expressions, which was related to slower response times following reward and punishment. 

Finally, in chapter six, a general summary and discussion of the different findings across all studies is provided. Theoretical and clinical implications are discussed and suggestions for future research are made.