Does Response Variability Predict Distractibility Among Adults With Attention-Deficit/Hyperactivity Disorder?

Zachary W. Adams, Walter M. Roberts, Richard Milich, Mark T. Fillmore

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


Increased intraindividual variability in response time (RTSD) has been observed reliably in attention-deficit/hyperactivity disorder (ADHD) and has often been used as a measure of inattention. RTSD is assumed to reflect attentional lapses and distractibility, though evidence for the validity of this connection is lacking. We assessed whether RTSD is an indicator of inattention by comparing RTSD on the stop-signal task (SST) with performance on the delayed oculomotor response (DOR) task, a measure of distractibility. Participants included 30 adults with ADHD and 28 controls. Participants completed the SST and the DOR task, which measured subjects' ability to maintain attention and avoid distraction by inhibiting reflexive saccades toward distractors. On the SST, the ADHD group was slower to inhibit than were controls, indicating poorer inhibitory control in ADHD. The ADHD group also displayed slower reaction times (RTs), greater RTSD, and more omission errors. On the DOR task, the ADHD group displayed more premature saccades (i.e., greater distractibility) than did controls. Greater variability in RT was associated with increased distraction on the DOR task, but only in ADHD participants. Results suggest that RTSD is linked to distractibility among adults with ADHD and support the use of RTSD as a valid measure of inattention in ADHD.

Original languageEnglish
Pages (from-to)427-436
Number of pages10
JournalPsychological Assessment
Issue number2
StatePublished - Jun 2011


  • ADHD
  • Adults
  • Eye movements
  • Variable attention

ASJC Scopus subject areas

  • Clinical Psychology
  • Psychiatry and Mental health


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