Autism and inner speech: a computational model of language functions in autistic flexible behaviour

Abstract

Experimental and computational studies propose that inner speech boosts categorisation skills and executive functions, making human behaviour more focused and flexible. In addition, many clinical studies highlight a relationship between poor inner-speech and an executive impairment in autism spectrum condition (ASC), but contrasting findings are reported. Here we investigate the latter issue through a previously implemented and validated computational model of the Wisconsin Cards Sorting Tests. In particular, the model was applied to detect the individual differences in cognitive flexibility and inner speech contribution in ASC and neurotypical participants. Our results suggest that the use of inner-speech increases along the life-span of neurotypical participants but is absent in ASC ones. Although we found more attentional failures in autistic children/teenagers and more perseverative behaviours in autistic young/older adults, only ASC children and ASC older adults exhibited a lower performance than matched control groups. Overall, our results corroborate the idea that the lower use of inner speech in ASC teenagers and young adults is compensated by alternative cognitive strategies (e.g., visual thinking), but it could represent a disadvantage for children (for the missing support of development) and older adults (for the missing compensation of cognitive decline). Moreover, the results suggest that cognitive-behavioural therapies should focus on developing inner speech skills in ASC children as this could provide cognitive support along their whole life span.