Bruno Bara, mental models, and syllogisms

We describe the history of psychological studies of syllogistic reasoning, focusing on Bruno Bara’s contributions to them. We point out the methodological problems in the early studies from 1908 until the first experiments that called for participants to draw their own conclusions from premises. This procedure led to theories of the mental processes underlying reasoning, and Bara was one of their pioneers. By the 1980s, there were (too) many theories, but in the current century, it was possible to winnow them. The most recent version of the theory based on mental models appears to give the best current explanation of syllogistic reasoning, but there remain unanswered questions, e.g., the processes underlying modal syllogisms, which concern possibilities.