Children with ADHD encounter multiple academic and interpersonal problems presumably due to insuf cient executive functions. In two studies we measured executive functions (i.e., shifting, resistance to distraction) and assessed whether children with ADHD can empower these functions by forming implementation intentions (i.e., if-then plans; Gollwitzer, 1999). Children with ADHD made fewer perseverative errors on a shifting task (Study 1) when instructed to make if-then plans. They also bene ted from if-then plans in solving math problems that required both working memory and the inhibition of distractions (Study 2). Results concerning implications for research on if-then planning in children with ADHD are discussed.1. For ease of exposition in this paper, the term ADHD is used constantly as an abbreviation for Attention-Deficit/Hyperactivity Disorder according to the DSM-IV combined subtype of ADHD and the ICD-10 category of Hyperkinetic Disorder.
PLANS BENEFIT EXECUTIVE FUNCTIONS IN ADHD 617Inattentiveness, impulsivity, and hyperactivity are the core symptoms of Attention Deficit Hyperactivity Disorder (ADHD).1 Children with ADHD are easily distracted by extraneous stimuli, have problems organizing activities, and lack inhibitory control. Prominent theories on ADHD suggest that ADHD-symptoms arise from deficits in executive functions because these deficits reliably differentiate children with ADHD from children without ADHD (Barkley, 1997). For instance, children with ADHD show worse performances compared to children without ADHD on tasks requiring planning, inhibition, task shifting, and working memory (Lijffijt, Kenemans, Verbaten, & van Engeland, 2005).Executive functions are commonly grouped into three types: (a) inhibition, (b) shifting, and (c) working memory (Miyake, Friedman, Emerson, Witzki, & Howerter, 2000).Inhibition involves the ability to inhibit dominant, automatic, or pre-potent responses. A typical inhibition task is the Stop Signal task (SST; Logan & Cowan, 1984), in which participants learn to discriminate between two different stimuli (i.e., X versus O) and in one-third of the trials an auditive stop signal is presented with a time delay after the presentation of the stimulus (e.g., 250 ms). In trials with a stop signal, participants are required to inhibit their response. Children with ADHD have difficulties to inhibit their response on stop trials and show a prolonged reaction time on Go trials as compared to children without ADHD and without any psychiatric diagnosis (Lijffijt et al., 2005).Another type of executive function encompasses the shifting back and forth between multiple tasks or mental sets (Monsell, 1996). Also referred to as task switching, shifting has been identified as an executive function that may play a role in failures of cognitive control in patients with brain injuries and psychiatric disorders (Miyake et al., 2000). Children with ADHD also have difficulties performing tasks that require shifting between mental sets and therefore consistently exhibit poorer performan...