In a classic demonstration of the experimenter expectancy effect, Robert Rosenthal and Kermit Fode (1963) had psychology students train genetically similar rats to run a maze. Students who were falsely told their rats were bred to be 'maze-bright' reported significantly faster learning times than students told their rats were 'maze-dull.' Data revealed that students expecting smarter rats unconsciously handled them more warmly and positively, proving that an experimenter's expectations can alter subject behavior and skew research outcomes.