FACT FICTION AND EXPERIMENTER BIAS EFFECT

Critically analyzes 31 studies which attempted to demonstrate that Es' expectancies and desires significantly affect the experimental outcome (E bias effect). The majority of studies do not clearly demonstrate the effect. Many of these studies are criticized for inadequacies in the analysis of results, e.g., failure to perform an overall statistical analysis to exclude the null hypothesis and failure to avoid probability pyramiding when postmortem tests are performed. 2 conclusions are drawn: (1) The E bias effect appears to be more difficult to demonstrate and less pervasive than was implied in previous reviews in this journal. (2) In those instances in which the effect was obtained, it was apparently due to one or more of the following: the student Es misjudged, misrecorded or misreported the results; they verbally reinforced their Ss for expected responses; or they intentionally or unintentionally transmitted their expectancies and desires by paralinguistic or kinesic cues. (2 p. ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1968 American Psychological Association.