FR-3 and FR-5

Goal (1): To start Shirley on an FR-3 schedule, meaning that after 3 consecutive presses on the bar Shirley would receive a reinforcement.
Goal (2): To start Shirley on an FR-5 schedule, meaning that after 5 consecutive presses on the bar Shirley would receive a reinforcement.

Procedure- An FR schedule is also known as a Fixed Ratio schedule. This means that after a certain number of responses (in this case 3 and 5) the behavior will be reinforced. Today's FR- 3 session started at 2:30 p.m. and lasted 30 minutes. Shirley weighed 215.5 grams (on both days of FR-3) and which is 7.5 grams above her goal weight. Shirley was to press the bar down 3 consecutive times in order to receive her reinforcement. The total training session resulted in 97 food presentations (290 bar presses). The second day of FR-3 resulted in 83 food presentations (250 bar presses).
The FR-5 training session was only one day long and started at 2:30 p.m. as well and lasted 30 minutes. Shirley weighed 216.5 grams and which is 8.5 grams above her goal weight. Shirley was to press the bar down 5 consecutive times in order to receive her reinforcement. The total training session resulted in 53 food presentations (267 bar presses).

Results and Discussion:

On the training day that Shirley was on the FR-3 schedule she was placed in the box and again went directly to the bar and started pressing. She kept pressing the bar down two times and checking the food hopper for a pellet. It took her a little while to catch on to pressing the bar down 3 times in order to receive a pellet, the same way she did for the FR-2 schedule. However, she did catch on faster to pressing three times in a row before checking the hopper than on the previous schedule. Sometimes during this training session she would press the bar down only one time and then leave and roam around the cage for a little while before returning to finish and getting a reward. This was the first time that she had done this. Usually Shirley works hard to get a reward, so this behavior was somewhat unusual for her. Later on into the session, however, Shirley would get a burst of energy and run to the bar and press down as much as she could before getting a reward. Because this behavior was so strange and Shirley was still not pressing three times consecutively, Carolyn and I decided to put her on an FR-3 schedule for a second day to see if her behavior changed. On the second day of FR-3 Shirley is much more engaged with the bar and presses it three times in a row more consistently. Although, she did not press as many times in the second day as the first her behavior was much more normal and she did receive a large amount of pellets. After the second day Carolyn and I decided Shirley would be fine to move on to FR-5.

In FR-5 Shirley went straight to the bar and pressed it multiple times with in the first few minutes of the session. With this schedule Shirley now presses the bar as many times consecutively as she can before receiving a reward. Carolyn and I asked Dr. Trench about this behavior and found out that it was normal for the rats to check the food hopper for their reward in-between presses in the normal schedule.  Had we known this we probably would not have held Shirley back on the FR-2 and FR-3 schedules. On the FR-5 schedule Shirley pressed the bar down over 100 times with in the first five minutes of training. Today she is also starting to show what looks like aggression toward the bar. She presses down vigorously and uses her teeth at some points which is something she has not been doing. I am thinking that this could be a sign of frustration for not being rewarded as frequently as she was in the past schedules.