The speaker says humans reach theoretical limits on some psychometric tasks, such as detecting whether a photon is present or absent.

“possible you could find better i mean humans are pretty good data efficiency wise but i doubt that they're at the like theoretical limits there are some things in psychometrics where people really are at the theoretical limits so like we can notice the presence or absence i think of a photon like you can't do better than that so um there are things where we're at the theoretical limits there are things where we're not like we are constrained”