Extinction: Sometimes Life is Unfair

   Today was the second day of extinction for Lilly, and I'll tell you this: she was NOT a fan. The goal of the second day was to drastically reduce the number of times Lilly actually pressed the bar, because she had learned that engaging in bar pressing would no longer provide rewards. On the first day of extinction, Lilly still consistently tried to press the bar, although it was at a much lower rate. By the time we got to our second session, you can see from the graph that she had drastically reduced her bar-pressing.
  When Lilly first understood that she wasn't going to get anymore treats, she began exhibiting some really interesting behaviors. First, she started pressing the bar like her life depended on it, which was an excellent example of an extinction burst. I could see that she was frustrated, and her behavior mirrored that frustration. After Lilly attempted to press the bar so many times, she took a little break and started biting on the plastic front of the cage, which was a behavior I hadn't observed in her before. She also started jumping at the light over the bar, as if she thought it would give her a treat if she did something to it. In addition, the number of times she pressed the bar decreased significantly as the session went on. After about 25 minutes of the session, she had almost completely stopped pressing the bar. Today, she's only pressed the bar 51 times in eight minutes (so far) which is a huge decline from her earlier records. I eventually terminated the training session after 23 minutes, because she hadn't pressed the bar in quite some time. I think Lilly might be getting the message- no more treats for her! Although I'm sure she didn't like it, I enjoyed watching her try a variety of behaviors to receive treats again. The graph of responses demonstrates her drastic decline in lever-pressing behavior, and you can see how much her behavior changed, especially on the second day. Sometimes life is rough for a rat!

	Extinction
Extinction Day 1
	5 Minutes	98
	10 Minutes	165
	15 Minutes	194
	20 Minutes	198
	25 Minutes	223
Extinction Day 2
	5 Minutes	42
	10 Minutes	51
	15 Minutes	51
	20 Minutes	51