Contamination sensitivity in autism, Down syndrome, and typical development § Efrosini Kalyva a,1 , Sandra Pellizzoni b,1 , Alessandro Tavano c , Paola Iannello d , Michael Siegal b,e, * a City College, Thessaloniki, Greece b University of Trieste, Italy c Scientific Institute E. Medea, Udine, Italy d Catholic University of Milan, Italy e University of Sheffield, UK Research in Autism Spectrum Disorders 4 (2010) 43–50 ARTICLE INFO Article history: Received 3 July 2009 Accepted 27 July 2009 Keywords: Autism Contamination Disgust Representation Theory of mind ABSTRACT Although typically developing children are attuned early to others’ communicative signals, one of the very first noticeable impair- ments in children with autism is in attending to voices and speech. Yet it is through conversations with others that children are made aware that apparently edible substances may in reality be contaminated. In two experiments, we examined contamination sensitivity in children with autism, typically developing children, and a group of children with Down syndrome. In Experiment 1, many children with autism who ranged in age from 4 to 10 years were prepared to drink liquids that had been contaminated by insects. There was evidence for a developmental delay as contamination sensitivity in autism was associated with increas- ing age. In Experiment 2, children with autism were prepared to drink liquids that had been contaminated by human hair or had insects in close proximity. By contrast, in both experiments, both typically developing children and children with Down syndrome demonstrated strong contamination sensitivity. We discuss the results in terms of constraints on the early learning of the edible– inedible distinction. ß 2010 Elsevier Ltd. All rights reserved. § This article was prepared with the support of a European Union Sixth Framework Marie Curie Chair and a grant from the Fondazione Benefica Kathleen Foreman-Casali. * Corresponding author at: Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TP, UK. E-mail address: M.Siegal@Sheffield.ac.uk (M. Siegal). 1 These authors contributed equally to the research reported here. Contents lists available at ScienceDirect Research in Autism Spectrum Disorders Journal homepage: http://ees.elsevier.com/RASD/default.asp 1750-9467/$ – see front matter ß 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.rasd.2009.07.005