I feel like it's one of these studies where there is deep importance not to read more into the conclusion than what it states.

So while expectation of time would be a factor, it wouldn't be the only factor and that alone couldn't break out of the physical constraints of the system.

I think hunger is comparable: one can be hungry over time as a result of the natural changes in their body, or they can become hungry merely by looking at appetising food. I think psychology can play a useful, but complicated role.