To finalize the shaping process of Tessa the Rat until she was consistently pressing the bar on a continuous reinforcement schedule. Successive approximations of bar-pressing behaviors were reinforced, and Tessa was reinforced for each bar press.
Procedure:
Training Session Three: Tessa was rewarded for any behavior resembling bar-pressing. This included rearing behaviors as well as approaches to the bar. Tessa was reinforced for placing her paws on the bar. This continued for a total of twenty minutes.
Training Session Four: Tessa was manually rewarded when she returned to the bar after leaving that side of the Operant box. She was reinforced for all bar-presses until she was consistently pressing the bar on an FR1 schedule. This continued for twenty-one minutes.
Results:
Training Session Three: Tessa received a total of 28 manual reinforcements for behaviors resembling bar-pressing. For example, Tessa was reinforced for approaching the bar from above but not from below. Likewise, rearing behaviors were only reinforced as she returned to her normal stance and crossed the bar threshold. Tessa pressed the bar 78 times, receiving a reinforcement for each bar-press.
Training Session Four: Tessa pressed the bar a total of 124 times and received a reinforcement for each bar-press. Manual reinforcements were used to encourage her to return to the bar after over thirty seconds of exploring other parts of the Operant box. Manual reinforcements were also given to encourage Tessa to approach the bar from above while not exploring the top of the cage (this was done by reinforcing rearing behavior as she returned to the height of the bar). She received a total of 6 manual reinforcements for such behaviors.
Discussion:
Training Session Three: Tessa became satiated quickly after receiving an adequate amount of reinforcements. This may have been caused by an increase in food intake from previous days of shaping when she performed at a much higher rate, received more reinforcements, and was fed an adequate amount of rat chow (around 5 grams each day in addition to consumed reinforcements). She performed at a rate of 30 bar-presses per five-minutes for the first ten minutes, then the rate dropped to zero by the end of twenty minutes.
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| Cumulative Record for Training Day Three |
Training Session Four: Tessa developed a clear association between the bar-pressing behavior and the immediate reinforcement of the behavior. She performed at a high rate for the majority of the training session, but she became satiated during the last three minutes of training. I felt confident to stretch the ratio of Tessa's reinforcement schedule after observing her progress in the Operant box. A video of her behavior on the FR1 schedule is below:
Training Session Three was performed at 3:00 on September 22nd, 2012.
Training Session Four was performed at 3:00 on September 24th, 2012.
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