Table 2.

Definitions for the testing stages of the training phase.

Stage	Description
1*	Reward offered by hand centered between the two wells
2	Reward placed uncovered in front of the right or left well
3	Reward placed in the right or left well, not covered by stimulus object
4	Reward placed in the right or left well, stimulus object placed behind the well containing the reward
5	Reward placed in the right or left well with a stimulus object covering half the well with the reward
6	Reward placed in the right or left well with stimulus object fully covering the baited well

^*This stage is used only if an animal balks at Stage 2 for one week (5 consecutive training sessions).

Stimulus object: appropriate-sized object, a toy in this case, used to cover a well containing a reward