Brain imaging has become an indispensable ingredient of experimental psychology. Until the 1970s or 1980s, it was fashionable to defend the functionalist thesis that psychology and neurobiology were autonomous disciplines, occupying watertight compartments. "The physical nature [of the brain] imposes no constraints on the forms of thought", asserted Philip Johnson-Laird in Mental models in 1983. Today, this idea has been abandoned, as examples of mutual constraints and fruitful interdisciplinary dialogues abound. In one direction, psychology is often the first to study and theorize a cognitive function: witness the example of evidence-based decision-making theory, developed in psychology as early as the 1960s before being confirmed and extended, thirty years later, to the neurophysiological level. For example, learning theory, which began with the behavioral studies of Ebbinghaus, Pavlov, Hull and Rescorla, made considerable progress with the advent of neural models, first speculative (Hebb) then increasingly based on experimentation and modeling in neuroscience (Kandel).
Brain imaging plays an essential role in the study of cognitive functions, as it is the only way to gain non-invasive access to the anatomical and functional organization of human brain circuits. Imaging methods have progressed considerably since their emergence some forty years ago. The aim of the 2018-2019 lecture was to take stock of these technical and methodological advances, to better understand the extent to which these methods succeed in clarifying the nature of mental representations in humans, and to discern their limitations.