To many, the poster child for David Marr's famous three levels of scientific inquiry is reinforcement learning – a computational theory of reward optimization, which readily prescribes algorithmic solutions that evidence striking resemblance to signals found in the brain, suggesting a straightforward neural implementation. Here we review questions that remain open at each level of analysis, concluding that the path forward to their resolution calls for inspiration across levels, rather than a focus on mutual constraints.
This page contains links to original data from experiments run at the Princeton Neuroscience Institute. These data are available to others for educational purposes. If they are used in publications, please cite the source of the data by indicating the published reference and the address of this website