Date of Award


Document Type


Degree Name

Master of Arts (MA)




Several studies suggest) that experimenters may influence subjects in experimental situations and thereby obtain the predicted results (Rosenthal, 1966). Thus, the results obtained in research may reflect (1) independent, and (2) bi. resulting from the communication of expectancies by the experimenter.

Although numerous investiga^ ons have considered characteristics of experir nters and subjects that facilitate expectancy communication, the experimenter effect remains inadequately explained (Fode, 1967). It was felt that the Investigation of an additional variable, internal-external locus of ontrol, (Rotter, 1954) might contribute further informationL Past research suggested that internal subjects are better influencers (Pharos, 1965), and that they are also more resistant to external influence (Crowne & Liverant, 1963).

Ninety-six subjects were asked to rate ten pictured individuals (previously standardized to be neutral) on a success-failure continuum. A 2 x 2 x 3 design was used, with two types of experimenteres (internal and external), two types of subjects (internal and external), and three treatment conditions (+5, -5, no bias). Twelve experimenters were assigned to a +5 expectancy, a -5 expectancy, or a no expectancy condition and ran four internal and four external subjects.

It was expected that internal experimenters would obtain more biasing than would external experimenters. Further, external subjects would be more susceptible to bias than internal subjects. The dependent va . Lable was tl. mean photo rating of each subject. A three-way analysis of variance supported none 'of the hypotheses. However, there was a tendency for internal subjects to ate photos more positively than external subjects.