limits on the phenomena that are valuable to study within aBayesianparadigm.Somephenomenawill surely be more satisfying to address at an al- gorithmic or neurocomputational level. For example, that a certain behavior takes peo- ple an average of 450 milliseconds to pro- duce, measured from the onset of a visual stimulus, or that this reaction time increases when the stimulus is moved to a different part of the visual field or decreases when the same information content is presented audi- torily, are not facts that a rational computa- tional theory is likely to predict.