Principal component analysis study of visual and verbal metaphoric comprehension in children with autism and learning disabilities

This research extends previous studies regarding the metaphoric competence of autistic and learning disable children on different measures of visual and verbal non-literal language comprehension, as well as cognitive abilities that include semantic knowledge, executive functions, similarities, and reading fluency. Thirty seven children with autism (ASD), 20 children with learning disabilities (LD), and 21 typically developed (TD) children participated in the study. Principal components analysis was used to examine the interrelationship among the various tests in each group. Results showed different patterns in the data according to group. In particular, the results revealed that there is no dichotomy between visual and verbal metaphors in TD children but rather metaphor are classified according to their familiarity level. In the LD group visual metaphors were classified independently of the verbal metaphors. Verbal metaphoric understanding in the ASD group resembled the LD group. In addition, our results revealed the relative weakness of the ASD and LD children in suppressing irrelevant information.

► Metaphors are classified according to their familiarity level in TD children.
► Metaphors are classified according to their type: visual or verbal in LD children.
► Most of the variance in the TD group is explained by the semantic knowledge.
► Results revealed the weakness of ASD and LD in suppressing meaningless information.