Wednesday, October 10, 2012

Extinction - Day 14 & 15






On day 14 and 15 of training, Monica did not receive any reinforcement for pressing the bar in order to extinguish the previously learned behavior.  This process is known as extinction.  When Monica entered the operant box, she went directly to the bar and began pressing.  After every few presses, she would stop and sniff the magazine in search of her reward.  Monica showed signs of frustration after about 40 presses and moved to the opposite corner of the box where she sniffed and gazed out of the clear wall.  
At first she spent about 30 seconds not paying attention to the bar and sitting in the opposite corner, but as the session continued, she completed longer time periods without pressing the bar.  On one occasion, Monica stared out of the box for two minutes straight, completely ignoring the bar and magazine.  
An extinction burst is the abrupt increase in a previously reinforced behavior after the reinforcement is removed.  The extinction burst was evident at the beginning of both extinction training sessions.  In the first five minutes, she pressed the bar 174 times on day 14 and 117 on day 15.  Monica's bar pressing behavior increased when her reinforcement was removed.   She also exhibited frustration by being more aggressive towards the bar.  As seen in the video clip, she exhorts great effort to press the bar and spins around the sides trying to figure out how to get reinforced.
Spontaneous recovery occurs when an organism is put back in a training situation and an extinguished behavior reappears.  I did not see this occur with Monica.  In the last minute interval on day 14, she pressed the bar 55 times; therefore, I do not believe that the behavior was yet extinguished.  During the same interval on day 15, she only pressed the lever 7 times, This drastic decrease in the bar pressing behavior shows that the behavior has been extinguished.  I believe that if Monica is placed in the operant box in the near future, spontaneous recovery would occur; she would press the bar again.




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