Thursday, October 10, 2013

Extinction of Learned Behavior


Extinction Day 1:


Date: 10/7/13
Start Time: 1:54
End Time: 2:24
Session Duration: 30:00
Number of Bar Presses: 129
Number of Rewards: 0
Snickerpuss’ Weight: 211

Extinction Day 2:
Date: 10/8/13
Start Time: 1:59
End Time: 2:09
Session Duration: 30:00
Number of Bar Presses: 40
Number of Rewards: 0
Snickerpuss’ Weight: 211



Goal:
Our goal was to extinct the behavior of bar pressing that we had previously taught Snickerpuss. During extinction no rewards were given for lever presses. We would consider Nicky to have successfully extinct the behavior of bar pressing when she pressed the bar less than 50 times during a 30 minute training session.

Procedure:

Extinction Day 1:
Nicky weighed 211 grams, which is two grams above her target weight, on the day of training. For the thirteenth day of training, we put Nicky on extinction, which would not reward Nicky for any lever presses.

Extinction Day 2:
Nicky weighed 211 grams, which is two grams above her target weight, on the day of training. For the fourteenth day of training, we again put Nicky on extinction again, which would not reward her for any lever presses

Results:

Extinction Day 1:
Nicky pressed the lever 129 times during our 30 minute training session, resulting in 0 rewards. We did not consider Nicky’s behavior to be extinct because she responded at a rate much higher than we set for our goal for the 30 minute session. Therefore we decided to repeat extinction again to see if a second day of training would increase response rate.

Number of responses per 5 minute increments for Extinction Day 1          
Time 
Bar Presses
0-5
13
6-10
14
11-15
26
16-20
12
21-25
40
26-30
24


Extinction Day 2:
Nicky pressed the lever 40 times during our 30 minute training session, resulting in 0 rewards. Nicky pressed the lever 89 times less than during yesterday’s extinction session, indicating that the process of extinction was working. Since Nicky pressed the lever less than 50 times during the 30 minute session, we considered extinction to be successful.

Number of responses per 5 minute increments for Extinction Day 2
Time 
Bar Presses
0-5
0
6-10
4
11-15
25
16-20
9
21-25
2
26-30
0


Discussion:
            Exctincting Snickerpuss’ learned behavior of bar pressing was a rather easy task for us. Nicky has a history of giving up on lever pressing when she was not rewarded quickly enough, as seen in her FR-10 training. On day 1 of extinction Nicky displayed a lot of frustrated behavior (self-grooming and rearing up), however, on the second day she showed less of this type of behavior. Day 1 had a fluctuating rate of responding for each 5 minute period, with a small extinction burst occurring between the 21st and 25th minutes. Day 2 of extinction saw a rather constant low rate of responding with 0 responses in the first and last 5 minute increments and a small extinction burst between the 11th and 15th minutes. We considered extinction to be successful because Nicky responded only 40 times on the second day of training. We were especially happy to see 0 responses during the last 5 minutes of extinction. Nicky’s lack of responding likely indicates that she has learned no matter the number of bar presses, no rewards are coming, which was exactly the goal of today’s session.

A video of Nicky during Extinction Day 1. Here she shows frustrated behavior such as biting the food hopper and repeatedly checking for food.

A video of Nicky during Extinction Day 2. Here she shows less frustrated behavior.

Cumulative Record for Extinction Day 1


Cumulative Record for Extinction Day 2

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