Incidence and functions of self-reported private speech in young adults: A self-verbalization questionnaire.
A self-report questionnaire assessing the use of self-directed speech was administered to 1,132 undergraduate university students. In general, self-verbalization scores were high. Exploratory factor analysis produced a four-factor solution that was readily interpretable in terms of Vygotskian theory. Consistent with the view that private speech serves as a cognitive tool system, the highest scores were reported for questionnaire items loading highly on a factor consisting of cognitive, mnemonic, and attentional uses of self-verbalization. The scales appear to have good internal consistency, high test-retest reliability, and good content and criterion validity.