To place Shirley on a FR-2 schedule. The purpose of this schedule is to have Shirley press the bar two consecutive times before she is rewarded with a chocolate pellet.
Procedure: Day 1
An FR schedule is also known as a Fixed Ratio schedule. This means that after a certain number of responses (in this case 2) the behavior will be reinforced. Todays session started at 2:30 p.m. and lasted 22 minutes. Shirley weighed 217.3 grams which is 9.3 grams above her goal weight. Shirley was to press the bar down two consecutive times in order to receive her reinforcement. I pressed the hand switch one time at the very beginning of the session to remind her that pressing the bar would result in a chocolate pellet. The total training session resulted in 113 food presentations (225 bar presses) not including the initial pellet that I presented to her.
The session on day 2 began at 2:30 p.m. and lasted 25 minutes. Shirley weighed 224.2 grams which is 16.2 grams above her goal weight. Shirley again needed to press the bar two consecutive times in order to receive a reward. There was no need to remind Shirley to press the bar- as soon as she was placed in the box she began to press the bar. This training session resulted in 86 food presentations (171 bar presses).
Results and Discussion:
Shirley was placed in the box on day one and after the first food presentation remembered that she needed to press the bar in order to receive food. She remembered very quickly that she had to press the bar down in order to receive a reward. However, many times she would press the bar down one time and check the hopper for a pellet and then when she realized there was not one she would go back to the bar and press it again, which would result in the presentation of the pellet. Shirley would also hold the bar down after one press and then check the food hopper, which made me wonder if she actually understood that she needed to press the bar down two times. Her routine on the first day would be to press, look in the hopper, press again, and then eat the pellet. Also she would press the bar, then hold it down for a second or two, then check the hopper and go back to the bar when there was nothing in there. It took her a little while to start pressing the bar down two times in a row before checking for pellets, however it was not consistent. She was more intrigued by the bar today and spent more time with it than during the previous days of training, and I was thinking this could be due to the fact that it is not rewarding her every time and therefore she is trying to figure out what is going on. Her behavior today was also a little bit crazy- she was literally jumping at the wall at one point during the session, which looked like she was trying to escape. I was not sure if this was a sign of frustration or if she was beginning to get satiated and therefore this was a sign of boredom (because it was occurring near the end of the session). This session only lasted 22 minutes because she was losing interest with the bar and was beginning to show signs of satiation. She would go to the front left corner and sit or sniff for a few minutes after pressing the bar in the beginning, but now the period of time she was spending in the corner was getting longer. We thought it would be best to quit while we were ahead today.
We decided to place Shirley on a FR-2 schedule again today even though she was rewarded over 60 times yesterday because we were not sure whether or not it was ok if she was not pressing the bar down twice before checking the food hopper. We thought that if she had a little more practice at this schedule then she would pick up on pressing it twice. In fact, she did press it twice before checking the hopper more frequently today. After being placed in the box, Shirley went straight to the bar and started pressing it down. Towards the end of the session she was pressing the bar down three times in a row which was a sign to us that she was ready to move on to an FR-3 schedule the next day. This training day did result in less food presentations, even though the session lasted longer than the previous day. Towards the end of today she was also going back to the front left corner of the box and sitting for long periods of time. After 25 minutes she was not frequently pressing the bar and we thought it would be best to end the session and move on to a new schedule tomorrow.
Shirley sitting in the front left corner of the box far away from the bar. This is her favorite spot to sniff.
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