Introduction

Episodic memory impairments in individuals with autistic spectrum disorders (ASDs) are quite selective and can be interpreted in terms of both retrieval and encoding impairments. For example, whilst recall of test items without specific cues (free recall) is often impaired in children with autism in relation to comparison groups, performance is relatively unimpaired when appropriate retrieval cues are provided at the test stage of the procedure (Boucher & Lewis, 1989; Boucher & Warrington, 1976; Tager-Flusberg, 1991). Bowler, Matthews and Gardiner (1997) found that adults with Asperger syndrome (AS), defined as high-functioning individuals on the autistic spectrum that met the International Classification of Diseases, 10th edition (ICD-10; World Health Organization, 1993) criteria for AS excluding the language criteria, were also unimpaired in cued-recall in comparison to typical adults. Impaired free recall and intact cued recall is consistent with a retrieval deficit and Bowler and colleagues proposed a ‘task support hypothesis’, in which they suggested that many of the mild memory impairments found in individuals with ASDs would be alleviated with appropriate support, particularly at retrieval.

Free recall is not always impaired in individuals with ASDs. For example, whilst children with low-functioning autism (LFA) were unimpaired in their recall of unstructured word-strings presented in the form of sentences, in relation to comparison samples, they were impaired in their recall of grammatically correct, structured sentences (Hermelin & O'Connor, 1967).