People's Negation Behavior: The Power of Content

People’s Negation Behavior: The Power of Content Cengiz Alacaci (alacaci@fiu.edu) Department of Curriculum and Instruction, Florida International University 11200 SW 8 th Street, Miami, FL 33199 USA Ana Pasztor (pasztora@fiu.edu) School of Computer Science, Florida International University 11200 SW 8 th Street, Miami, FL 33199 USA on correct negation rates; comparing correct negation rates of Co- and NCo-sentences allowed us to assess the content effect on negation behavior before and after formal training. Keywords: negation; quantifiers; content effect. The Problem In this paper, we present a study on the effect of content on people’s ability to negate quantified sentences. Most results on people’s difficulties in reasoning with negation occur as part of research on deductive reasoning. While rule-based theories agree that deductive reasoning is content-dependent (Manktelow & Over, 1990), recent mental model theories use the principle of truth to explain/predict reasoning errors, whereby people have difficulty mentally representing what is false according to the premises. This is particularly true in the case of quantified reasoning (Yang & Johnson-Laird, In an earlier study (Pasztor & Alacaci, 2005), we showed that in the case of quantified sentences, not only do people not build mental models of their negations, but more often they don’t know how to negate them correctly in the first place. To our surprise, we also found little evidence of con- tent effect, a fact that we attributed to the lack of semantic connection between the sentences in our instrument. To fur- ther test the power of content on people’s negation behavior, in our new study we embedded the sentences in a story con- text that created a strong semantic link among them. Results and Discussion Table 1. Correct negation rates for Co- and NCo-sentences before and after formal instruction. Co1 Co2 Co3 Co4 Co5 Pretest Posttest NCo1 NCo2 NCo3 NCo4 Pretest Posttest Methods Although the rates of correct negation of Co-sentences were relatively low before instruction, they increased signifi- cantly after (11.8 vs. 22; df=39, p 0.1), which may be due to the ceiling effect. Our instrument contains a story in which King Bumaga, the king of an exotic island, gives a speech to foreign dignitaries to promote tourism. However, he suffers from a disease called negatitis: sometimes he utters sentences that contra- dict the sentences he actually means to say. Nine such sen- tences are embedded into the text. Participants were invited to translate these into what the king actually meant to say before negatitis affected them. Five have negations that are believable but counter-intuitive regarding the goal of pro- moting tourism. We call these Co-sentences. Their purpose is to create a conflict between having to choose sentences that intuitively fit the story content and having to produce formally correct negations. The remaining four (henceforth NCo-) sentences do not carry this potential for conflict. The nine sentences were given in mixed order. Forty junior computer science students participated in the study. They were tested at the beginning and at the end of a semester-long formal logic course. The pre-post compari- sons allowed us to assess the effect of formal logic training Acknowledgments Pasztor’s work was partially supported by NSF grants EIA- 9906600, HRD-0317692, and CNS-042615, and ONR grant N00014-99-1-0952 with the CATE Center at FIU. References Manktelow, K. I. , & Over, D. E. (1990). Inference and Un- derstanding. A Philosophical and Psychological Perspec- tive. London: Routledge. Pasztor, A. , & Alacaci, C. (2005). On people’s incorrect ei- ther-or patterns in negating quantified statements: A study. Proceedings of the 27th Annual Conference of the Cognitive Science Society. Hillsdale, NJ: Erlbaum. Yang, Y. , & P.N. Johnson-Laird (2000). How to eliminate illusions in quantified reasoning. Memory and Cognition 28, pp. 1050-1059.