Five attempts to replicate the experimenter bias effect.

Abstract

Five investigations, involving SOI Ss and SI £s, were conducted to crossvalidate an earlier study (Rosenthal & Fode, 1963, Exp. 1) that bad clearly demonstrated the Experimenter Bias Effect. Each of the five investigations failed to demonstrate that £s' expectancy-biases influence their results (overall F<1.0). The five investigations are related to other studies in this area, the majority of which also failed to demonstrate the Experimenter Bias Effect. It is concluded that the effect is more difficult to demonstrate than was implied in several recent reviews and that, at the present time, it is not known what preconditions are necessary to obtain it.A recent text (Rosenthal, 1966) delineated several ways that an experimenter might inadvertently influence the results of his research. These "experimenter effects" include an Experimenter Personal-Attributes Effect in which the characteristics or personality traits of the experimenter-for example, his sex, age, race, anxiety, need for approval, hostility, and dominance-influence his 5s' performance. They also include an Experimenter Bias Effect in which E's expectancies, hypotheses, desires, or biases affect the results. For instance, an Experimenter Bias Effect would be present if Es obtain significantly higher scores from 5s on a standard test when they expect high rather than low scores.This paper is concerned only with the Experimenter Bias Effect. There is little doubt that Es generally expect or desire to obtain different results from 5s assigned to different 1 These investigations were supported by research grants (MH-07003 and MH-I1S21

Personality

“…This year, Barber and his associates (18) and Wessler & Strauss (349 ) have published the results they obtained from a series of studies attempting to duplicate and document the magnitude of unconscious experimenter determination of experimental outcomes originally reported by Rosenthal in one situational context (stu dent experimenters running other students in a rating study ). Their nega tive fi ndings raise doubts about the pervasiveness of this biasing effect.…”

Teacher Suspiciousness of Experimenter's Intent and the Meditation of Teacher Expectancy Effects

“…In their review, Rosenthal and Rubin (1978) quantitatively combined the results of 345 studies of interpersonal expectancy effects and concluded that the reality of the phenomenon was no longer an issue and that the mean size of the effect was clearly not trivial (i.e., d = .70 or r = .33). ' However, many individual studies have failed to find a significant expectancy effect (e.g., Barber, Calverley, Forgione, McPeake, Chaves, Bowen, 1969;Rosenthal, Persinger, Mulry, Vikan-Kline, & Grothe, 1964;Wessler & Strauss, 1968), and some have even found results in the opposite direction; that is, expected behavior occurred less in those who were expected to display more of it (e.g., Adler, 1973;Claiborn, 1968Claiborn, , 1969. It has been suggested (Rosenthal, 1969;Brophy & Good, 1974) that this failure to find an expectancy effect may be due to the subjects' awareness (or suspiciousness) of the experimental manipulation.…”

Classroom Teacher and Teacher‐in‐Training Susceptibility to Stereotypical Bias

“…Several models have been suggested in which a number of conditions must be met before a biasing factor actually influences the behavior of a child. Barber, Calverley, Forgione, McPeake, Chaves, and Bowen (1969) delineated an eight-step model describing the potential effects of teacher expectancy on child performance: The teacher must attend to, comprehend, and retain the expectancy; the teacher must transmit the expectancy to the child; the child must attend to, comprehend, retain, and act on the expectancy. Researchers have begun the task of investigating various components of the Barber et al model to determine the effects of expectancy in the classroom setting.…”

“…Laboratory experiments not directly related to the educational milieu have suggested that the status difference between the agent and subject (Barber et al, 1969) and the sex of the agent (Rosenthal, 1964) may relate to the establishment of a bias effect. Within an educational framework, Schain (1972) suggested that the sophistication of the teacher population may influence the bias effect, and Carter (1969) found that internal versus external locus of control influenced the way teachers-in-training reacted to a biasing influence.…”