Investigating syntax in autism: Comparisons with SLI, links with cognition Recent work exploring syntax in autism spectrum disorders (ASD) has identified morphosyntactic deficits and argued that these are independent of non-verbal reasoning. More specifically, researchers have now claimed that subgroups with ASD have syntactic profiles reminiscent of Specific Language Impairment (SLI), the latter showing a dissociation between language deficits and non-verbal intelligence. With this work, we investigate the nature of syntactic impairment in ASD, its parallelism with SLI and its potential relation to other aspects of cognition, namely non-verbal intelligence, working memory and theory of mind (ToM). We focus on a clinical marker of SLI that has scarcely been studied in ASD, namely 3rd person accusative clitic production, which has moreover been hypothesized to solicit working memory Downloaded by [La Trobe University] at 13:53 31 May 2016A c c e p t e d M a n u s c r i p t 2 resources. We also explore 1st person accusative clitic production, largely preserved in SLI but hypothesized to be specifically affected in ASD due to reported difficulties with pronouns of the 1st and 2nd person, arguably related to difficulties in ToM.Our participants included 21 individuals with ASD (aged 5-16), 22 individuals with SLI (aged 5-16) of similar age, as well as age-matched and younger controls. Experimental tasks were conducted to evaluate the production of 1st and 3rd person accusative clitics, the latter being a clinical marker of syntactic impairment. We also administered standardized tasks assessing general morphosyntax, verbal working memory (digit-span tasks and non-word repetition), nonverbal reasoning (Raven's Progressive Matrices) and ToM (Sally-Anne).Overall scores for both clinical groups reveal quantitatively similar deficits for 3rd person accusative clitics and general morphosyntax. However upon closer inspection a significant subgroup of children with ASD showed intact grammatical skills. The only weakness identified across the entire ASD population was for 1st person clitics, which was mastered by children with SLI. However the task used to elicit these required perspective shifting and thus the lower scores which resulted can be accounted for in terms of the well-documented ToM deficits in ASD. This is further supported by the observation that better scores at ToM tasks led to improved performance with 1st person accusative clitics. In addition, difficulties on all working memory measures were revealed for ASD and SLI and crucially found to correlate only with performance on 3rd person clitics in both groups. In contrast, non-verbal reasoning did not correlate with any syntactic measures.