Who Moved My Cheese?

Food presented to the North 60% of the time
Relying on cues yields rewards 65% of the time
If the reliability of the cue strategy drops below the 60% threshold, the subject is better off ignoring cues and always going North
How long of an unlucky streak will subject tolerate before abandoning a cue and switching to the strategy of just always going North?
What if probability of food to North changes?

Food presented to the North 60% of the time