Developmental differences in the understanding of beliefs and desires

Seventy-two children between the ages of 3 and 5 took part in an investigation of the relations between the development of understanding of the two core concepts of theory-of-mind - desires and beliefs. Desire understanding was assessed by tasks requiring fulfilled or unfulfilled desires to be recalled and to predict desire-related emotions. Belief understanding was measured using false-belief task in standard and social version. Results showed that 3-year-olds have difficulty with the understanding of unfulfilled desires and false beliefs. In addition, specific links were found between the understanding of unfulfilled desires and false belief performance. These links suggest that the understanding of unfulfilled desires may be some kind of developmental bridge between the understanding of simple 'contentive' and more complex 'indicative' form of mental representations. The implications of these results for theory-of-mind development are discussed.