Logical thinking serves as an essential skill useful in any situation. When people are asked to define what it means to think logically, however, their responses are often vague. In one of her latest publications, Professor Masako Watanabe of Nagoya University's Graduate School of Education and Human Development addresses this ambiguity from a sociological perspective. After its release in October 2024, "Ronriteki shikō to wa nani ka" 論理的思考とは何か (What is logical thinking?) caught the public's attention, selling over 50,000 copies within just four months. We spoke with Professor Watanabe about her research on logical thinking and what inspired her to pursue this topic.

Experiencing an "Invisible Cultural Clash" at an American University

Walk into any bookstore and you will find shelves filled with books on logical thinking. Although most of them contain advice along the lines of "state your conclusions first, then present supporting arguments," Professor Watanabe points out that this is simply "American-style" logical thinking. Through over 35 years of research, she has shown that this style is just one among many. Logical thinking, she explains, is shaped by factors such as culture and communication purpose.

Her research on logical thinking began in New York City. When she entered Columbia University, the first essay she submitted was rejected as "ungradable." Despite repeated revisions, it was returned with comments like "unclear" and "explain more." That was when she encountered the American writing model. Once she adapted to it, her grades improved dramatically. "The content had not changed, but just switching how I wrote made all the difference." This shocking experience led her to explore the differences between logical and non-logical thinking, and what truly defines logical thought.

Professor Watanabe has been a faculty member at the Graduate School of Education and Human Development since 2007.

Observing Classrooms and Educational Approaches in Different Countries

First, to compare the U.S. and Japan, Professor Watanabe conducted writing experiments in each country. Students were shown the same four-panel comic, and she examined how they explained and justified its sequence. She also analyzed language and history classes, as well as textbooks to explore how writing instruction influences children's thought and expression.

After earning her Ph.D. from Columbia University, she returned to Japan and continued her research at the University of Tokyo's Institute of Social Science and the International Research Center for Japanese Studies. During this time, she discovered that France had its own distinct logic and expressive style, leading her to include it as a comparative point. She conducted fieldwork in France over the course of 15 years, observing elementary through high school classes. Once her research there was complete, she turned to Iran as the fourth country for study. "I read language and history textbooks from Grade 1 through Grade 12 in all four countries and observed the classes," she explains. Her research findings grew steadily with each passing year.

An English language class in the U.S. (Provided by Professor Watanabe)

A history class in Japan (Provided by Professor Watanabe)

Due to political instability, Professor Watanabe was only able to visit Iran once. She said that it took about five years to gather sufficient comparative data. (Provided by Professor Watanabe)

The "Logic" of Logical Thinking Is Not Universal

Based on her fieldwork in these four countries, Professor Watanabe categorized the respective styles of thought and expression: the U.S. as "economic," France as "political," Iran as "legal-technical," and Japan as "social."

The American style aims to persuade through efficient argumentation, placing importance on whether communication is efficient. In contrast, the French style focuses on examining all possibilities, resolving contradictions, and applying the outcomes for the public good, placing value on the depth of deliberation.

The approach in Iran places emphasis on upholding truth and adhering to norms, using proverbs and poetry to reach religious or moral conclusions. The key criterion is alignment with truth. In Japan, as demonstrated by the type of book reports assigned in elementary school, the emphasis is on whether the writing evokes sympathy, focusing on shared experience and the maintenance of social order.

Through this analysis, Professor Watanabe asserts that "logical thinking is neither universal nor fixed. I encourage people to adapt their logic to suit the purpose at hand."

Creating a Beginner-Friendly Guide in Response to High Demand

The book is an adaptation of "'Ronriteki shikō' no bunkateki kiban: Yottsu noshikō hyōgen sutairu" 「論理的思考」の文化的基盤：４つの思考表現スタイル (The Cultural Foundations of "Logical Thinking": 4 Styles of Logical Expression), a monograph by Professor Watanabe from 2023 that was written with specialists in mind. Although the earlier book garnered media attention, its high price as an academic-oriented publication made it less accessible. "There were requests to publish the material in a form that could reach a broader audience," says Professor Watanabe, "so I reworked it as a paperback." Even before its release, pre-orders poured in, prompting a reprint decision ahead of publication.

Readers have described the book as eye-opening: "I have often been told that Japanese people are illogical, and I was bothered by that, but now I understand things better." The book is also set to be adopted as a first-year education textbook at several universities starting next academic year.

Professor Watanabe is already planning her next projects: "After outlining the structure of this new society that we describe as 'postmodern,' I would like to think about what that type of society needs from its education system. I want to write a policy proposal on how and when the four styles of logical expression should be introduced, covering a wide range from elementary school through university. Also, I hope to publish the previous academic monograph that formed the basis for this book in English."

Researchers from fields beyond sociology and education have also expressed that the study has served as a source of inspiration for their own work.

This article was originally written in Japanese by Tatsuhiko Maruyama for the "Public Relations Meidai" web magazine and published on February 10, 2025. The Nagoya University International Communications Office has translated and edited it for clarity while preserving the original content's intent. Certain information might be outdated. For the original Japanese version, please see here.