Experiment 3

Task:

Rats were given two signals one with high pay and the other with low pay. In the high pay condition rewards are always dropped while in low pay condition rewards are given in treatment probablities of 1, .5. and .25. The begin of a trial could randomly between 1-60 seconds and ended once the first reponse was given.

The idea is that the signal in the low pay condition would indicate decreased anticipation leading to increased response variation.

Figure 7

The data shows the effect but only weakly.

The authors argue that the reason is because after the rats respond they know that in due time a new trial with a new oppurtinity to get award is coming. Therefore they are still anticipating a reward which is keeping why response variation is supressed.

 Figure 8

The top panel shows the intertrial button response. As the time neared the next trial the resposne variation decreased indicating that the rats trackign time since last response.

The bottom panels shows that the response variation increases as the probablity of reward decreases.

Experiment 3 failed to show a strong effect supporting the hypothesis that as reward anticpation is reduced response variation increases. The resason given for this is becasue the task enabled rats to track the time between responses. Since the rat knew another trial was imminent after response they still were able to anticpate a reward.