Sniffy

*Dr. Trench: This post includes both the "Sniffy" post and the "Real Rat vs. Virtual Rat" post

Sniffy is the name of my virtual rat. In order to prepare for training Li'l Swanson, my real rat, I used a computer program that simulates training a rat in an operant box. The virtual box and rat were much like my box and rat: 

 

The small golden-brown nugget-like object that Sniffy is sniffing is the reward (food) and it is sitting in the box's magazine. Directly above the magazine is the lever that I shaped Sniffy to press. Just like Li'l Swanson, I had to first magazine train Sniffy (train him to associate a particular sound with food arriving in the magazine), then shape Sniffy by using that learned association to reward him for performing successive approximations of pressing the lever. Magazine training Sniffy took me about 25 minutes, and shaping him took me about 45 minutes. Magazine training Sniffy and Swanson were very similar, and both fairly easy. They both took around the same amount of time (20-25 minutes); the biggest difference was the number of times I had to activate the magazine--I had to feed Sniffy many more pellets before he associated the noise and food than I had to feed Swanson. Because I had never trained a rat before, I found shaping Sniffy to be more difficult than shaping Li'l Swanson even though it took me much less time to shape Sniffy (45 minutes vs. 2-ish hours). Shaping Li'l Swanson was probably easier because I somewhat knew what to expect because of my practice with Sniffy. It was also more difficult to shape Sniffy because it was hard to tell sometimes when Sniffy was performing one of the successive approximations of the target behavior--for example, I began by reinforcing Sniffy whenever he faced the bar, but sometimes the computer would lag for a second and I wouldn't get the timing of the reinforcing perfectly right, or it would be difficult to tell if Sniffy was actually facing the bar (his body would be pointed towards it but his face would be at a slight angle away from the bar), and I had a hard time determining if the computer recognized that I was rewarding the desired behavior. 

After Sniffy was completely shaped (was pressing the bar voluntarily and often in order to receive food), I put him on a VI5 schedule of reinforcement. A VI5 schedule, or variable interval 5 schedule, reinforces the rat when it presses the bar for the first time after an interval of about 5 seconds has passed (the interval could actually be anywhere from about 3-7 seconds, but the average amount of time that would have to pass before Sniffy could get rewarded for pressing the bar was 5 seconds). This is Sniffy's cumulative record for the VI5 schedule:

And this is Swanson's cumulative record for FR5, to compare:

Notice how, at the beginning, Sniffy pressed the bar over and over, expecting a reward. However, after trial and error--pressing the bar and not getting rewarded unless about 5 seconds had passed since the last reward, Sniffy eventually started pressing the bar about every 5 seconds, causing the cumulative record increase at a constant rate (see 2nd image above). Li'l Swanson's bar pressing is more irregular than Sniffy's bar pressing (after he had gotten used to the schedule, that is). This difference could be simply because of the variations in Swanson's behavior because Swanson is a real rat, or because of the differences between fixed ratio and variable interval schedules.

After Sniffy had mastered the VI5 schedule of reinforcement, I bumped him up to a VI10 schedule of reinforcement, where he would get reinforced the first time he pressed the bar after approximately 10 seconds had passed since the last reinforcement. This is the VI10 cumulative record:

Notice how, again, as time goes on, Sniffy's responses (bar presses) become more regular as he learns the schedule of reinforcement. 

There are both strengths and weaknesses of using live and virtual rats. The virtual rats are much easier to deal with--you don't have to feed them, or weigh them, or change their bedding. However, the computer program does not factor in the differing personalities you get in different rats, or the variations in the rats' behavior. Training Sniffy was fairly straightforward, and training Swanson was a little more complicated--I had to make sure that I didn't train Swanson to fixate too much on the light in the box, which wasn't something that Sniffy would have done. I think Sniffy was a perfect training tool to practice on before we trained our real rats, and I would recommend continuing to use both--I think that the experience you get training Sniffy before your real rat is invaluable.