Curiosity Learning

Up until now, we have considered just the extrinsic or external rewards an agent may receive in an environment. The Hallway example, for instance, gives a +1 external reward when the agent reaches the goal, and a -1 external reward if it gets the wrong goal. However, real animals like us can actually learn based on internal motivations, or by using an internal reward function. A great example of this is a baby (a cat, a human, or whatever) that has an obvious natural motivation to be curious through play. The curiosity of playing provides the baby with an internal or intrinsic reward, but the actual act itself gives it a negative external or extrinsic reward. After all, the baby is expending energy, a negative external reward, yet it plays on and on in order to learn more general information about its environment. This, in turn, allows it to explore more of...