Animist thinking in the elderly and in patients with Alzheimer’s disease Deborah Zaitchik Massachusetts General Hospital, Boston, MA, USA, and Harvard Medical School, Boston, MA, USA Gregg E. A. Solomon National Science Foundation, Arlington, VA, USA Some patients with Alzheimer’s disease (AD) reveal low-level impairment in their concepts of living things (i.e., forgetting that zebras are striped). To test for more profound impairment, we investigated the concept alive—a “higher order” concept spanning every member of the domain. Many elderly con- trols were animists, attributing life to inanimates capable of self-generated activity (the sun, fire). Most AD patients were animists, with half even attributing life to inanimates whose activity is not self-generated (cars, lamps). Adult animists, like young children who have not yet acquired biological concepts, overattributed life to active inanimates. We believe this reflects an innate disposition to view active entities as agents, and that agency interferes with the biological concept alive. This interference, we suggest, reflects degradation of biological concepts in the face of spared perception of agents. It sheds light on the nature of fundamental questions concerning conceptual organization, innate endowment, and conceptual change. Keywords: Folkbiology; Conceptual change; Domain-specificity; Aging; Alzheimer’s disease. Numerous studies of brain-damaged patients support a claim of category-specific impairment in the domain of living things (Capitani, Laiacona, Mahon, & Caramazza, 2003; Caramazza & Shelton, 1998; Forde & Humphreys, 1999; Humphreys & Forde, 2001; Tyler & Moss, 2001). This category appears to fractionate into two distinct subcategories: animals and fruits/ vegetables (Capitani et al., 2003). The suggestion has been made that, for evolutionary reasons, knowledge about animals (as predators and prey), as well as fruits and vegetables (as food and toxins), have special status in the conceptual system, special locations in the brain, and consequently special vulnerabilities to certain kinds of brain damage (Caramazza & Shelton, 1998). Several studies of patients with Alzheimer’s disease (AD) have reported the presence of a cat- egory-specific impairment for living things (Whatmough & Chertkow, 2002). Tasks on which patients have shown category effects include identification questions, picture naming, Correspondence should be addressed to Deborah Zaitchik, Gerontology Research Unit, MGH-East (149–2691), 149 13th Street, Charlestown, MA 02129–2000, USA (E-mail dzaitchiksamet@partners). We thank Marilyn Albert, Susan Carey, Sarah Helmstadter, Jerry Samet, Yaakov Stern, and the Hebrew Rehabilitation Center for the Aged. The first author was supported by a grant from the National Institutes of Health (NIH/NIA AG020548), and the second author was supported by the National Science Foundation. # 2008 Psychology Press, an imprint of the Taylor & Francis Group, an Informa business 27 http://www.psypress.com/cogneuropsychology DOI:10.1080/02643290801904059 COGNITIVE NEUROPSYCHOLOGY, 2008, 25 (1), 27 – 37