ORIGINAL PAPER Preserved Proactive Interference in Autism Spectrum Disorder Joana C. Carmo 1 • Elsa Duarte 1 • Sandra Pinho 2 • Carlos N. Filipe 3 • J. Frederico Marques 1 Ó Springer Science+Business Media New York 2015 Abstract In this study, we aimed to evaluate further the functioning and structuring of the semantic system in aut- ism spectrum disorders (ASD). We analyzed the perfor- mance of 19 high-functioning young adults with ASD and a group of 20 age-, verbal IQ- and education-matched individuals with the Proactive Interference (PI) Paradigm to evaluate semantic functioning in ASD (Experiment 1). In Experiment 2, we analyzed the performances of both groups in a PI paradigm with manipulation of the level of typicality. In both experiments, we observed significant effects of trial and group but no trial by group interactions, which we interpreted as robust evidence of preserved PI (build up effect) that indicated the preservation of semantic mechanisms of encoding and retrieval. Keywords Autism spectrum disorder Á Semantic memory Á Categorization Á Typicality Á Episodic memory Introduction Autism spectrum disorder (ASD) is a developmental dis- order that is currently characterized by the presence of both persistent deficits in communication and social interaction in combination with a pattern of restricted, repetitive behaviors and interests in which symptoms must be present from early childhood (DSM–V, American Psychiatric Association 2013). Specifically, the social interaction symptoms might manifest as an inability to maintain competent conversation, whereas the social communication symptoms comprises both verbal and non-verbal commu- nication deficits. It is well known that verbal communica- tion heavily depends on categorization and conceptual knowledge or semantic memory (e.g., Lakoff 1987; Barsalou 1992; Murphy 2004). However, the hypothesis that the language and communication impairments com- monly found in ASD could be explained in terms of deficits at this level was abandoned for some time (Tager-Flusberg 1996). This present study sought to contribute to the evaluation of this hypothesis by analyzing in a finer manner the functioning of categorization and semantic processing in ASD. Research evaluating the general functioning of the long- term memory system (LTM) in ASD has generally found a pattern of preserved function in terms of overall recollec- tion performance (Minshew and Goldstein 1993; Renner et al. 2000). However, several lines of evidence suggest that although the overall levels of free recall might be unimpaired in individuals with ASD, these individuals exhibit an atypical pattern of semantic processing in memory facilitation (i.e., a pattern that leads to superior recall) (e.g., Toichio 2008). An initial line of evidence in favor of this hypothesis came from a study by Tager- Flusberg (1991) in which the participants were required to Electronic supplementary material The online version of this article (doi:10.1007/s10803-015-2540-4) contains supplementary material, which is available to authorized users. & Joana C. Carmo joanacostadocarmo@gmail.com 1 Faculdade de Psicologia, Universidade de Lisboa, Alameda da Cidade Universita ´ria, 1649-013 Lisbon, Portugal 2 Centro de Apoio ao Desenvolvimento Infantil, Edifı ´cio CADIn, Estrada da Malveira, 2750-782 Cascais, Portugal 3 Nova Medical School, Faculdade de Cie ˆncias Me ´dicas, Universidade Nova de Lisboa, Campo Ma ´rtires da Pa ´tria, 130, 1169-056 Lisbon, Portugal 123 J Autism Dev Disord DOI 10.1007/s10803-015-2540-4