RT Journal Article
SR Electronic
T1 Policies or Knowledge: Priors differ between perceptual and sensorimotor tasks
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 132829
DO 10.1101/132829
A1 Claire Chambers
A1 Hugo Fernandes
A1 Konrad Paul Kording
YR 2018
UL http://biorxiv.org/content/early/2018/01/15/132829.abstract
AB If the brain abstractly represents probability distributions as knowledge, then the modality of a decision, e.g. movement vs perception, should not matter. If on the other hand, learned representations are policies, they may be specific to the task where learning takes place. Here, we test this by asking if a learned spatial prior generalizes from a sensorimotor estimation task to a two-alternative-forced choice (2-Afc) perceptual comparison task. A model and simulation-based analysis revealed that while participants learn the experimentally-imposed prior distribution in the sensorimotor estimation task, measured priors are consistently broader than expected in the 2-Afc task. That the prior does not fully generalize suggests that sensorimotor priors strongly resemble policies. In disagreement with standard Bayesian thought, the modality of the decision has a strong influence on the implied prior distribution.NEW AND NOTEWORTHY We do not know if the brain represents abstract and generalizable knowledge or task-specific policies that map internal states to actions. We find that learning in a sensorimotor task does not generalize strongly to a perceptual task, suggesting that humans learned policies and did not truly acquire knowledge. Priors differ across tasks, thus casting doubt on the central tenet of may Bayesian models, that the brain’s representation of the world is built on generalizable knowledge.