I think of it this way. If a dog, for example, gets too close to a fire, it gets burned and will usually avoid fire afterward. But if it's being trained and gets a reward whenever it does something right, it usually takes a few times for it to make the connection between the action and the reward.

I guess what I'm getting at is that living creatures survive by avoiding the bad things, so they have to learn fast, and remember for a long time. But the good things tend to be harder to remember when they aren't tied to survival.

Okay. I'm done.