Intelligence and personality characteristics associated with accuracy in rating a co-twinʹs personality

The relationship between measured intelligence and personality and accuracy in rating the personality traits of a same sex co-twin was examined. Participants completed a standard timed adult intelligence test, a personality inventory measuring 20 personality traits and personality adjectives corresponding to the 20 personality scales. Participants also completed the personality adjectives in a manner in which they felt would be descriptive of their co-twin. The results suggest that, in general, accuracy in personality judgments is related to verbal intelligence and to personality characteristics associated with an intellectual personality and not due to a twin projecting their personality onto their co-twin or due to actual similarity between twins.