The Role of Ambiguity in the Interpretation of Noun-Noun Compounds

The Role of Ambiguity in the Interpretation of Noun-Noun Compounds Phil Maguire (phil.maguire@ucd.ie) Arthur W.S. Cater (arthur.cater@ucd.ie) School of Computer Science and Informatics University College Dublin, Ireland Edward J. Wisniewski (edw@uncg.edu) Department of Psychology, University of North Carolina at Greensboro, USA Abstract Gagne and Shoben (1997) proposed that people are aware of how concepts are typically used to modify other concepts and that this modifier relation frequency influences the ease with which concepts can be combined. However, Wisniewski and Murphy (2005) suggested that Gagne and Shoben’s conditions of relation frequency were confounded with plausibility. We conducted an experiment which investigated whether ratings of plausibility respond to relation frequency, a possibility that has been suggested by Gagne and Spalding (in press). We found that, when participants were provided with full descriptions of the combinations’ referents, differences in plausibility between conditions of modifier relation frequency disappeared. A second experiment investigated why this should be the case. We found that many combinations were interpreted with a variety of relations, contrary to assumptions made by Gagne and Shoben (1997). Correlation analyses revealed strong associations between combination plausibility and measures of objective and subjective ambiguity, suggesting that the differences observed in Experiment 1 were most likely due to differences in combination ambiguity. We discuss the influence of ambiguity and the implications for Gagne and Shoben’s (1997) CARIN theory. Keywords: Conceptual combination; noun-noun compounds; plausibility ratings; ambiguity; CARIN theory. Introduction Concept combination is a ubiquitous phenomenon, as evidenced by the volume of lexicalized compounds entering the English language (e.g. soccer mom, beer gut) and the frequent spontaneous use of such phrases in reference to novel concepts or ideas (e.g. peasant dance, penguin film). Not only can people understand concepts like chocolate or rabbit in isolation, they can also understand them in combination (i.e. chocolate rabbit). Recently, the area of conceptual combination has attracted much attention in cognitive science because of its potential to further our understanding of conceptual representation as well as language production and comprehension in general. In their Competition Among Relations in Nominals (CARIN) theory, Gagne and Shoben (1997) proposed that the interpretation of a noun-noun combination occurs when a relation linking the two concepts is identified. According to this theory, the ease of interpretation of a combination is principally influenced by the relative frequency with which the appropriate relation has been previously used with the modifier noun. For example, since combinations involving the modifier mountain frequently use the relation, then it should be easy to interpret a combination like mountain goat while mountain magazine (a magazine mountains) should be more difficult. As support for their theory, Gagne and Shoben (1997) demonstrated that when participants made speeded sensicality judgments for a set of combinations, those involving low modifier frequency relations took longer to interpret than those involving high modifier frequency relations, while the head noun’s relation frequency had no discernible effect. Wisniewski and Murphy (2005) challenged the reliability of these results by suggesting that the observed patterns in response time were primarily due to differences in the familiarity and plausibility of the stimuli. When they asked participants to rate the plausibility and familiarity of Gagne and Shoben’s combinations, they found that low relation frequency items were rated as reliably less plausible and less familiar than the high frequency ones. Furthermore, these variables accounted for a far greater portion of the variance in sensicality judgment response time than did modifier relation frequency. Gagne and Spalding (in press) countered this argument. They demonstrated that subjective familiarity can be influenced by relation frequency and that relation strength emerges as a significant predictor variable in multiple regressions involving measures of objective familiarity. Similarly, they defended the confounding of relation frequency and plausibility by interpreting the latter as a dependent variable. According to their view, plausibility is what theories of conceptual combination should seek to explain and therefore, on the pain of circularity, it should not be conceived of as an explanatory variable. As an explanation for why low frequency items were rated as less plausible, Gagne and Spalding suggested that plausibility might be responding to modifier relation frequency. However, we believe that plausibility is very much an independent variable, and one which should intuitively influence ease of interpretation. The combination plastic toy is plausible by virtue of the fact that many toys are made of plastic. In contrast, cooking treatment is less plausible since the action of cooking does not suggest how it might be used as a treatment. Because this combination is unsupported by world knowledge it is more elusive and consequently, less plausible.