square at the right side of the front of the box. The door was at the left side of the front. On January 12th I put this box in No. 3's cage, the door of the box being open. I put a bit of food in the box. No. 3 reached in and took it. This was repeated three times. I then put in a bit of food and closed the door. No. 3 pulled and bit the box, turned it over, fingered and bit at the hole where the lever was, but did not succeed in getting the door open. After ten minutes I took the box out. The monkey having failed by his own impulsive efforts to depress the lever, I began the tuition. I took No. 3 out and let him sit on my knees (I sitting on the floor with the box in front of us). I would then put my hand out toward the box and when he was looking at it would insert my finger and depress the lever with as evident a movement as I could. The door, of course, opened, and No. 3 put his arm in and took the bit of food. I then put in another, closed the door and depressed the lever as before. No. 3 watched my hand pretty constantly, as all his experiences with me had made such watching profitable. After ten such trials he was put back in the cage and the box put in with a large piece of food in it and its door closed. No. 3 failed in the course of five minutes to get the door open. His behavior was just the same as it had been before he had seen me open the door ten times. He had not profited at all by my example. Later I showed him 15 times more and then tried him by himself. He failed as before.
The two monkeys. No. 1 and No. 3, were given a number of such chances to learn acts from seeing me. Other, boxes were used, the doors of which could be opened by pulling up a bolt, pulling out a plug, pushing a bar back into a slot, unwinding a wire and pulling a loop off from a nail. I had also certain pieces of apparatus arranged which would throw a bit of food down a chute into the cage when some simple mechanisms were operated; when for instance a nail was pulled out of a hole or a loop pulled off a nail or a bar pushed in. These could be set up outside the cages so that the monkeys could reach them through the wire netting and could easily see me operate them.
No. 1 had in all eight chances to learn from seeing me. In seven of the cases he failed utterly after seeing me operate the mechanisms 21, 5, 10, 4, 15, 40 and 15 times respectively. He did succeed in one case where the act required was to pull a wire loop off a nail. This must, I think, have been an accident. The other monkey failed utterly to learn to do the same thing though he had continued tuition.
No. 3 had seven chances to learn from seeing me. In five out of the seven he failed after seeing me operate the mechanisms 40, 30, 25, 5 and 30 times respectively. In the case of the other two, although he succeeded in getting the door open, it was not by doing as I had shown him. I opened a door 25 times by pulling a bolt up, but he opened it by pulling and pushing at the door itself until he worked the bolt up out
