Understanding intention and desire in the second year : developmental changes and relations among these abilities

The present experiments investigated the developmental change in infants' concept of intention, and the link between intention and desire understanding in the second year. In Experiment 1, we compared 14- and 18-month-old infants' ability to differentiate between intentional and accidental actions. In Experiment 2, we compared 18-month-olds' ability to infer subjective desires for objects and their performance on the previous task. Also, performance on these theory of mind tasks was correlated with mental lexicon six months later. A developmental progression in infants' understanding of intention was observed. Surprisingly, 18-month-old infants were unable to infer subjective desires for objects. No relationship was found between infants' understanding of intention, desire, and their mental lexicon. These results have methodological and theoretical implications for research exploring theory of mind in infancy

Infants' concept of intention : investigating inter-task relations and development continuities

The objective of the present thesis was to examine infants' understanding of other people's intentions. The first paper was designed to systematically investigate whether the tasks currently being used to tap into infants' understanding of intentional action are actually measuring the same underlying abilities. Infants completed two visual attention tasks when they were 10 months of age: a goal-detection task and an action-parsing task. Approximately four months later, infants were invited back to the laboratory to complete two imitation tasks: a behavioral re-enactment task and a selective action imitation task. Infants' concurrent performances on the visual attention tasks were linked; however, no association between their performances on the imitation tasks was observed. Interestingly, infants' performances on the visual attention tasks at 10 months predicted their performance on the behavioural re-enactment task, but not their performance on the selective action imitation task, at 14 months. In the second paper, the issue of developmental continuities was explored. The goal of this paper was to investigate whether infants' performance on the selective imitation of intentional actions task would predict their use of internal state language and/or their theory of mind abilities later on. Towards this purpose, 14- and 18-month-olds completed an imitation task that required them to distinguish intentional from accidental actions. At approximately 32 months, children's use of internal state terms was assessed via parental report. Finally, when children were 4 years of age, they were retested with an interactive game measuring intention understanding, a battery of general theory of mind tasks, and the Peabody Picture Vocabulary Test. Importantly, infants' performance on the selective action imitation task was linked to their performance on the preschool intention task. Moreover, children's use of internal state language at 32 months predicted their theory of mind skills at 4 years of age. Taken together, the results of the present thesis support the hypothesis that there is developmental continuity in children's understanding of intention from infancy through the preschool years. Results from these two papers also provide evidence to support the validity of various experimental procedures that are currently being used to tap infants' understanding of intentional actio

The role of gaze direction and mutual exclusivity in guiding 24-month-olds' word mappings

In these studies, we examined how a default assumption about word meaning, the mutual exclusivity assumption and an intentional cue, gaze direction, interacted to guide 24-month-olds' object-word mappings. In Expt 1, when the experimenter's gaze was consistent with the mutual exclusivity assumption, novel word mappings were facilitated. When the experimenter's eye-gaze was in conflict with the mutual exclusivity cue, children demonstrated a tendency to rely on the mutual exclusivity assumption rather than follow the experimenter's gaze to map the label to the object. In Expt 2, children relied on the experimenter's gaze direction to successfully map both a first label to a novel object and a second label to a familiar object. Moreover, infants mapped second labels to familiar objects to the same degree that they mapped first labels to novel objects. These findings are discussed with regard to children's use of convergent and divergent cues in indirect word mapping contexts