Achievement Motivation and Intelligence Test Scores: A Test of the Yerkes-Dodson Hypothesis

The old Yerkes-Dodson hypothesis of an inverted t -shaped relationship between strength of motivation and level of performance is tested for intelligence test scores. Resultant Achievement motive is measured with the Mehrabian-scales. Four motive groups (quartiles) arc formed. Intelligence is measured with Drouth’s “Test voor Niet-Verbale Abstractie” (non-verbal abstraction) in a neutral and in a high ego-involvement condition. The latter condition is supposed to arouse the achievement-related motives strongly. As hypothesized the most highly motivated group in the high ego-involvement condition performs significantly lower than the less highly motivated subject group. In the neutral condition an inverted U-shaped relationship is neither expected nor found. Secondary analyses using the data from all eight subject groups correspond with the hypothesis. Important practical implications are discussed.