Frank,

I think mammals are definitely further along than the other classes of animals. I have always had dogs and besides training I have had a lot of interaction with them. I have observed a lot of behavior that doesn't quite fit conditioning. For example, I have witnessed what seems to be best described as emotion and I have also ... I think ... observed them reacting to dreams when they sleep. With conditioning, we expect the response to be to avoid a negative outcome or to achieve a positive one. Yet I have observed behavior where there seemed no resultant outcome fitting this criteria. In some cases, like the expression of jealousy, the outcome they achieve is a negative one and yet they not infrequently continue to express the behavior even though they receive negative stimuli. So it's difficult to really understand what is going on in their gray matter but that is part of the enjoyment of having them around. With regards to fish, the conditioned behaviors do the same and make having them around much more fun. So its kind of like the difference between dog that share the house with the humans. The interaction between the species is much richer. So the difference is comparable to a person who has a pond he feeds and a person whose experience with fish is fishing for them at the local lake. The complexity of interaction between the species is richer in the pond where the owner feeds his fish.