I had to personally train a rat to press a bar. In my Intro to Psych class, we set up metal boxes with only a bar with a treat tray next to it and a glass window. When the rat pressed the bar or we pressed a button, a treat would fall into the tray. The lab used pretty basic conditioning and 99 percent of the rats pressed the bar by the end of the two weeks. We each paired up and visited our rat every day for two weeks. All we had to do was press the button every time she got near the bar until she understood she should press it herself.
Easy enough, right? Wrong.
We got our rat, nicknamed her Mozzy (short for Mozzerella) and we visited her every day. She seemed to warm up to us and got in and out of the box easily.
But she never pressed the bar.
Listen, we did everything we could, okay? We fed her the exact amount she was supposed to be fed. We held her gently so she wouldn’t be afraid. We dimmed the lights since rats are nocturnal.
She slept. She turned her back to the lever.
We trained her to get into the transfer bucket just fine. She saw what the other rats were doing and she seemed to understand that we would give her treats if she went near the lever.
Oh, she knew what she was doing, that little punk. She may not have had any idea of the anxiety she was causing us to have but if she did, then those cute red eyes truly represented her devilishness. She probably laughed about it with the twenty other rats who actually did what they were supposed to.
I finally understood why rats eat their young.
Matt, our rat TA, tried to help us as much as he could. He taught us any tricks he knew to get Mozzy to cooperate.
At the end of the two weeks we had a “Rat Parade” where everyone showed off how well they trained their rat. We went in the order of success. The first rat had gotten to press the bar 300 times in 15 minutes. All fifteen other rats were just as successful.
And then there was Mozzy.
Matt waited until everyone else had left to bring Mozzy out. She performed just as well as she had the last two weeks: not at all.
After fifteen minutes of her almost pressing the bar (probably just to mock us) we gave up. We put her away, said goodbye, and left little Mozzy with the other rats.
We got a good grade, because we documented Mozzy and her misadventures as well as we could. Still, our adopted rat child let us down.