Mental Models and Reasoning Lab

Welcome

“Deduction is that mode of reasoning which examines the state of things asserted in the premisses, forms a diagram of that state of things, perceives in the parts of the diagram relations not explicitly mentioned in the premisses, satisfies itself by mental experiments upon the diagram that these relations would always subsist, …and concludes their necessary, or probable, truth.” – Charles Sanders Peirce

At Princeton’s Mental Models and Reasoning Lab, we investigate the strengths and failures of human reasoning. The MMR Lab focuses on basic research and experimental data, as well as developing computational models of higher-level cognitive processes.

Experimental data in cognitive psychology suggest that rather than using rule-based, proof-theoretic reasoning, humans reason and solve problems through the use of internal representations that can be mentally scrutinized and processed. The theory that posits the existence of such models and the mechanization thereof, known as mental models theory, was established by Philip Johnson-Laird (1983) and has proven extremely powerful in predicting and explaining higher-level cognition in humans.

This theory departs from the standard view, which assumes that there is a formal logical or probabilistic calculus in the mind. “Formal rules of inference play no part in inferences,” says Johnson-Laird, “though from Piaget onwards, psychologists have proposed theories based on them.”