Do children with autism use the speaker's direction of gaze strategy to crack the code of language?

Normal toddlers infer the referent of a novel word by consulting the speaker's direction of gaze. That is, they use the Speaker's Direction of Gaze (SDG) strategy. This is a far more powerful strategy than the alternative, the Listener's Direction of Gaze (LDG) strategy. In Study 1 we tested if children with autism, who have well-documented impairments in joint attention, used the SDG or the LDG strategy to learn a novel word for a novel object. Results showed that although 70.6% of children with mental handicap passed the test by making the correct mapping between a novel word and a novel object, via the SDG strategy, only 29.4% of children with autism did so. Instead, their reliance on the LDG strategy led to mapping errors. In Study 2 a group of normal children, whose chronological age (24 months old) was equated with the verbal mental age of the 2 clinical groups in Study 1, was tested using a similar procedure. Results showed that 79% of this normal group passed the test by making the correct mapping between a novel word and a novel object using the SDG strategy. Taken together, the results from both studies suggest that children with autism are relatively insensitive to a speaker's gaze direction as an index of the speaker's intention to refer. This result is consistent with previous findings showing that children with autism are relatively "blind" to the mentalistic significance of the eyes. Discussion centers on how the absence of an SDG strategy might disrupt specific aspects of language development in autism.