Effects of a significant-other observer on neuropsychological test performance.

The present study examined the effects of a third-party observer on neuropsychological test performance in a sample of 30 university students seeking evaluation for learning disability. A significant-other (defined as a parent, sibling, close friend, spouse, or partner) observed portions of a neuropsychological testing session. Subjects were administered a battery of tests, including seven repeatable measures, chosen to assess diverse neuropsychological functions. In the presence of an observer, performance deficits were found on tests of attention, speed of information processing, and verbal fluency. An observer had no effect on tests of cognitive flexibility or motor speed. Our results suggest that the validity of test results may be compromised by the presence of an observer.