Does a Third Party Observer Affect Neuropsychological Test Performance? It Depends

Abstract

This study is a meta-analysis of available literature examining the effect of an observer on cognitive task performance. Of the 210 identified relevant articles, 62 met inclusion criteria yielding a final sample with 4405 individuals (2496 observed cases, 1909 not observed). The overall effect size was significant (d = −0.24), i.e., the presence of an observer was associated with poorer performance. However results were moderated by the effect size calculation method, cognitive domain, visibility of the observer, and number of observers. Attention, learning/memory, and delayed recall tasks were most adversely impacted by the presence of an observer.

Keywords:

• Third party observer
• TPO
• Social facilitation
• Social inhibition

Notes

¹ Wagstaff et al. (2008) assessed visual memory in an eyewitness format, which is qualitatively different from neuropsychological literature and therefore removed. Two other studies (Cox, 1966; Sawyer & Noel, 2000) were removed because the study effect size was greater than 3 SD from the effect sizes of other studies employing similar tasks. Removal of these two latter motor tasks resulted in an overall motor domain effect size that appeared to be a more accurate representation of the combined effect of all the motor studies.

² One study examined the effects of a TPO on effort testing (Yantz & McCaffrey, 2007). The combined, unweighted effect size for these measures, i.e., computerized Test of Memory and Malingering (Tombaugh & MHS Staff, 2001) and Word Memory Test (Green, 2003) revealed a facilitating effect of a TPO (immediate recall: d = 0.26; delayed recall: d = 0.21). Because these tests are typically used to measure effort and not cognition (i.e., memory), they were not included in this meta-analysis.