Figure 11. Behavioral predictions of the model.
(A) Differential predictions of the multiplicative (linear) and drive-reduction (non-linear) forms of reward. In our model, assuming that the internal state is at (A), outcomes larger than result in overshooting the setpoint and thus a declining trend of the rewarding value (B). Previous models, however, predict the rewarding value to increase linearly as the outcome increases in magnitude. (C) Our model predicts that when given a choice between two options with equal net effects on the internal state, animals choose the option that first results in reducing the homeostatic deviation and then is followed by an increase in deviation (green), as compared to a reversed-order option (red).