Poster #35 - Reasoning About Forces and Motion Through Thought Experiments

• In Event: 3-003 - Poster Session 09
  In Poster Session: PS 09 Section - Cognitive Processes

Integrative Statement

Scientific Thought Experiments (TEs) are hypothesis testing experiments that are carried out in the mind. Although TEs have been at the forefront of many scientific and mathematical advances (Kuhn, 1977), there has been no systematic empirical work within cognitive and developmental science focusing on how scientific TEs advance knowledge. In particular, it is not clear how TEs that stem from the mind, and not from observation of the world, lead to new knowledge about the world. Historians and philosophers of science have offered several different, but not mutually exclusive answers to this paradox: i) TEs evoke mental simulations that tap into embodied perceptual and motor procedures, where seeing the outcome of the simulation can be considered similar to the process of data collection (Gendler, 1998); ii) TEs are arguments where the learner begins from known premises and executes an inductive or a deductive argument that leads to new knowledge (Norton, 1996); iii) TEs highlight contradictions among beliefs, which can in turn illuminate the exact way in which nature does not agree with the currently held beliefs (Kuhn, 1977); and iv) TEs invite the construction of a mental model that can be used to draw inferences from (Nersessian, 1992).
We began testing some of these hypotheses in the context of a well-documented misconception about forces and motion according to which objects set in motion receive an impetus (a force inside the object while it is moving), which slowly dissipates and becomes weaker, leading to the slowing down and eventual stopping of the object (McCloskey, 1983). We asked whether and under what circumstances can TEs attenuate the impetus misconception. A total of 382 adult participants were recruited on MTurk and participated in two conditions in a Pre-Intervention – Intervention – Post-Intervention design. In both conditions, the Pre and Post-Intervention TEs were identical and were designed to elicit impetus responses. Similarly, in both conditions, the Intervention TEs were identical and evoked perceptual-motor procedures consistent with Newtonian mechanics. In one condition only (Inference Condition), participants were asked to agree or disagree with an explicit inference that followed from the Intervention TEs. The inference was in direct conflict with the impetus responses.
The results showed that the majority of incorrect responses at pre-training were indeed impetus responses. Furthermore, although participants gave more responses consistent with Newtonian mechanics on the Intervention TEs compared to Pre-Intervention TEs (p<.001), they did not spontaneously notice a conflict between the outcomes of their Pre-Intervention and Intervention TEs. That is, there was no significant change between Pre- and Post-Intervention TEs (p=.45). Only participants in the Inference Condition who were explicitly reasoning about the inference that followed from the Intervention TEs changed between Pre- and Post-Intervention TEs (p<.001). These results were replicated with slightly modified TEs and a new sample of 383 participants. The present findings will be discussed in light of the proposals about how TEs can lead to new knowledge and in light of an existing literature on explanation and its role in learning (Lombrozo, 2012).

Authors

• Igor Bascandziev, Reed College
  Presenting Author

• Susan Carey, Harvard University
  Non-Presenting Author