The effect of experimenter bias on the performance of the albino rat
Rosenthal and Fode gave twelve students from a senior experimental psychology course groups of naive albino rats to train in a maze. Six students were told their rats were maze-bright and six that theirs were maze-dull, though the rats had been assigned to the labels at random. The main analysis covered sixty rats, thirty under each label. The rats labelled bright performed better overall, with a rising learning curve against a levelling one for the rats labelled dull, and they made correct choices faster overall. The authors observed some prodding of rats in both groups and judged it unlikely to explain the difference.
Rosenthal and Fode gave twelve students from a senior experimental psychology course groups of naive albino rats to train in a maze. Six students were told their rats were maze-bright and six that theirs were maze-dull, though the rats had been assigned to the labels at random. The main analysis covered sixty rats, thirty under each label. The rats labelled bright performed better overall, with a rising learning curve against a levelling one for the rats labelled dull, and they made correct choices faster overall. The authors observed some prodding of rats in both groups and judged it unlikely to explain the difference.
Written from the full text, 2026-11-02.
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Rosenthal, R., & Fode, K. L. (1963). The effect of experimenter bias on the performance of the albino rat. Behavioral Science, 8(3), 183-189. doi:10.1002/bs.3830080302 https://doi.org/10.1002/bs.3830080302