Fig 1.
Different types of rake-shaped tools.
(A) Rakes A and B used during training. These two rakes had guides on each end of the blade to prevent the reward from rolling out from the inside of the blade. (B) Rake C used in the positional discrimination test.
Fig 2.
Flowchart of the food-obtaining training, the rake-pulling training, the rake-choice training, and the positional discrimination test.
The operation of the sliding door of the experimental box was introduced irrespective of the phase that each rat reached. Each daily experimental session comprised 40 trials throughout this experiment.
Fig 3.
Arrangements of the reward in Phases 1, 2, and 5 of the food-obtaining training.
Each red circle indicates the position of the reward.
Fig 4.
Arrangements of rakes and rewards during the rake-pulling training, the rake-choice training, and the positional discrimination test.
Each red circle indicates the reward position. (A) The arrangements of Rake A or B and the reward in the rake-pulling training. (B) An example of the arrangement of Rakes A and B and rewards in the rake-choice training. (C) The arrangement of Rakes A and B and rewards in pre-trials during rake-choice training. (D) The arrangement of Rake C and the reward in the positional discrimination test.
Fig 5.
The spatial arrangements of the rakes and rewards in the rake-choice training.
Each red circle indicates the position of the reward. (A) The spatial arrangements of the rakes and rewards of the appropriate options. (B) The spatial arrangements of the rakes and rewards of the inappropriate options. Regarding the first three options, the experimenter presented only the rake without presenting the reward.
Fig 6.
Individual (BN41–BN48) success and choice rates of the appropriate rake in the rake-choice training, and individual success rates in the positional discrimination test.
Each black circle indicates the success rate during the training, and each white circle indicates the success rate in the test. Each gray circle indicates the choice rate of the appropriate rake in the positional discrimination test.
Fig 7.
Individual (BN41–BN48) correct-direction rates in the positional discrimination test.
The broken line indicates chance level (*p < 0.05, **p < 0.01).
Table 1.
Individual rates of the ipsilateral trials in the positional discrimination test.