Separating the chaff from the oats: Evidence for a conceptual distinction between count noun and mass noun aggregates q Erica L. Middleton, a, * Edward J. Wisniewski, b Kelly A. Trindel, b and Mutsumi Imai c a Department of Psychology, University of Illinois at Urbana-Champaign, 603 East Daniel St., Champaign, IL 61820, USA b University of North Carolina at Greensboro, USA c Keio University, USA Received 10 December 2002; revision received 20 February 2004 Abstract The English language makes a grammatical distinction between count nouns and mass nouns. For example, count nouns but not mass nouns can be pluralized and can appear with the indefinite article. Some scholars dismiss the distinction as an arbitrary convention of language whereas others suggest that it is conceptually based. The present studies examined this issue with respect to aggregates (i.e., entities composed of multiple constituents that are generally homogenous). Experiment 1 demonstrated that participants rate the elements of familiar count noun aggregates (e.g., grapes and toothpicks) as more perceptually distinguishable than those of familiar mass noun aggregates (e.g., rice and confetti). They also were more likely to interact with one or a few elements of count noun aggregates but with multiple elements of mass noun aggregates. Experiment 2 replicated these results using a different sample of aggregates. In Experiments 3 and 4 manipulation of these factors predicted whether participants labeled a novel aggregate with a novel count or mass noun. These results show that for aggregates, count and mass noun usage is to a large degree con- ceptually based. The conceptual basis is consistent with the principle of cognitive individuation: speakers conceptualize the referents of count nouns as distinct individuals and the referents of mass nouns as non-individuated entities. However, we also identified exceptions to this view and suggest that they arise from linguistic convention or competing linguistic functions. Ó 2004 Elsevier Inc. All rights reserved. Keywords: Count noun; Mass noun; Cognitive individuation; Individual; Concept; Number; Syntax In the English language, most nouns are classified as either count or mass depending on their grammatical behavior. 1 For example, mass nouns (but not count nouns) can be preceded by quantifiers such as ‘‘much’’ q This research was funded by NSF Grant BCS-9975198 given to the second author. The first author thanks John Dunlosky for his suggestions in the writing of this article, Chris Lamb for his technical support, and Katherine Rawson for her patient and adroit advice in all matters relating to the first authorÕs future career as a scientist. The second author thanks Bob Dylan for providing some of the inspiration for this work. * Corresponding author. E-mail address: emiddlet@s.psych.uiuc.edu (E.L. Middle- ton). 1 Many languages in addition to English distinguish count nouns from mass nouns. However, not all languages make this distinction, particularly classifier languages such as Japanese and some Native American languages. 0749-596X/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.jml.2004.02.005 Journal of Memory and Language 50 (2004) 371–394 Journal of Memory and Language www.elsevier.com/locate/jml