KOSTAS HATZIKIRIAKOU and PANAYIOTA METALLIDOU TEACHING DEDUCTIVE REASONING TO PRE-SERVICE TEACHERS: PROMISES AND CONSTRAINTS Received: 22 June 2006; Accepted: 13 November 2007 ABSTRACT. This paper broadly addresses the question of whether university students whose major does not require expertise in logic can improve their ability in deductive reasoning by taking an introductory course in logic. In particular, our study aims to evaluate a course in deductive logic offered by one of the authors in a department of elementary education. Two experiments were conducted by using a pretest-posttest design with an experimental and a control group as well as a follow-up test after 6 months on the experimental group. The results of the analyses showed that the course mainly succeeded in strengthening students’ general logical ability in the experimental group and these gains were retained 6 months later in the follow-up test. Promises and constraints of the study are discussed in the educational context. KEY WORDS: arguments, deductive reasoning, logical thinking, pre-service teachers, tableau method, truth tables, Venn diagrams INTRODUCTION This paper broadly addresses the question of whether university students whose major does not require expertise in logic can improve their ability in deductive reasoning by taking an introductory course in logic. In particular, we evaluate a course in deductive logic offered by one of the authors in a department of elementary education in Greece, where a course in deductive logic is not usually offered by departments of elementary education. The situation seems to be similar in the U.S., where, though the NCTM Principles and Standards of School Mathematics asks for the promotion of the reasoning abilities of the students, the prospective teachers “do not have a feeling for what is or is not a valid deduction or what it means for statements of various forms to be true or false”. The lack of specific training in logic for both in service and prospective teachers is also noted by Pier Luigi Ferrari and Carlo Marchini (1996) in their review article on educational research on teaching and learning logic in Italy. It is not unreasonable to hypothesize that this widespread situation is partially due to the excesses of the New Math The names of the authors are listed alphabetically. International Journal of Science and Mathematics Education (2009) 7: 81Y101 # National Science Council, Taiwan (2007)