March 4, 5, and 6, 2016.
For these training days, I put Remy on a Fixed Ratio 2 schedule of reinforcement. You may be wondering what that sentence means, so here are a few quick definitions. According to the definition from our class lecture, a schedule of reinforcement determines when a response (bar press) will be followed by a reinforcement (receiving food in the magazine). Schedules are important because reinforcements in real-life learning situations are rarely given every time that a wanted behavior occurs.
There are quite a few different types of schedules of reinforcement, but for Remy I will begin by administering a Fixed Ratio (FR) schedule, which is dependent on the number of responses indicated after the letters FR. So, FR2, which I started with Remy today, means that she only gets a reinforcement every OTHER time she presses the lever. It is a fixed ratio (2:1) between the number of bar presses (2) and receiving food in the magazine (1). (Technically when I was shaping Remy, I was using the FR1 schedule--still a ratio of bar presses and receiving food in the magazine, it's just 1:1).
Thus, my goal for these three days of training has been for Remy to still consistently press the bar and not become discouraged by the lack of reinforcement for every odd number of bar presses. The purpose of this is to get Remy to tolerate schedules of reinforcement which show that she has truly learned the behavior.
Now that Remy is shaped, I don't have to do much in the way of procedure to get her to do what she knows she is supposed to in the operant box--pressing the bar for reinforcement. Although, it is still important to manage her and make sure she stays close to her target weight. This way she will be food motivated for each training session. On each day, the training sessions took place at 4:30 PM. Remy's weight fluctuated between 198.1 grams and 201.9 grams, about 90% of her starting weight and within 2 grams of her target weight of 200 grams.
The results of Remy being on FR2 were largely successful. On March 4, she had 94 bar presses (47 reinforcements); on March 5, 74 bar presses (37 reinforcements); and March 6, 127 bar presses (63 reinforcements). Respective cumulative records showing her progress are below.
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| March 4 Cumulative Record |
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| March 5 Cumulative Record |
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| March 6 Cumulative Record |
Discussion:
The cumulative records for each of these show a few interesting things that I would like to point out. First, Remy's performance day-to-day tended to fluctuate. I attribute this to differences in motivation, probably based on levels of general interest and/or her seemingly ever-present anxiety. For example, on the second day (March 5) of FR2, she seemed very agitated and spent much of her time in the front corner of the box after 20 minutes of the session--you can see this in the cumulative record tapering off. Also, there are parts of these cumulative records generally indicative of an FR schedule called a post-reinforcement pause--they can be visualized on the graphs by stretches of horizontal lines. Post-reinforcement pauses usually happen after each reinforcement, but with Remy they tended to happen between the first and second bar press. She would walk around the cage or groom herself as a way of taking a break before going back to work. Humans do this type of thing a lot, too; we know it as procrastination!
Overall, Remy has done pretty well so far in regards to my goal for tolerating schedules of reinforcement. I will attempt to stretch the ratio (gradually shaping Remy to work longer/harder for reinforcement) in the following training days to further test the strength of her learned association between a bar press and reinforcement. While you readers anxiously await the next installment of this gripping saga, here's a picture of Remy after getting a carrot (thanks Dr. Trench!) and a video of her being rambunctious just because that's how she is sometimes...
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| Snack time!! |
Until next time!
-Jessica
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