Daniel Dennett claims (in conversation and I think in his book Kinds of Minds) that a necessary condition for moral agency was having an ability to represent to oneself rules governing how one or others should behave. He further claims that humans are the only animals that can do this. Thus, only humans can be moral agents.
I think you can make a case that representing rules to oneself is not necessary. Maybe humans don't represent rules to themselves either. I something think about the consequences of my actions, but I don't know that I represent rules to myself very often. Still, I'd like to think I'm a moral agent even when I don't do that. Anyway, that's not the point of this little post. I have an example that looks to show that some animals besides humans can represent to themselves rules governing how they should behave.
Here's some background information relevant to the story. Dogs have a dominance hierarchy. They behave in various ways that either establish the hierarchy, enforce it or show what the hierarchy is. One of these behaviors I call the game of chicken. The way our German Shepherds play chicken is that one of dog will charge headlong at the other dog from one side and he/she either swerves at the last moment or the other dog dodges out of the way. I'm not sure whether they do this to establish dominance or to show that dominance once it has been established in some other way. But the rule is fairly simple: the submissive dog gives way to the dominant dog.
Of course, the fact that the dogs follow this rule does not mean that they represent that rule to themselves. Even a rock can follow a rule without representing it. However, I think dogs do represent this rule to themselves. Here's the story.
One day in the yard I call over McCoy, the giant old goof of a German Shepherd. He charges straight toward me with just a little too much enthusiasm. At first I think that he's going to stop or swerve, but after a moment I realize that he cannot stop and his freakishly large, heavy head is headed at a dog-gallop straight at my crotch. Then, at the last moment, he ducks his head and goes through my legs instead of crashing into me. I sigh in relief and turn around.
As I turn around one of the other dogs, Tasha, the dominant dog (or bitch, to be technical), knocks McCoy down growling at him. She almost never asserts dominance over McCoy (this is only the second or third time in several years), so this is unusual. She's clearly enforcing the chicken rule. She has to understand, in some way, what the rule is and that it has normative force.
Unless there is some way she can enforce this rule on the other dog without representing the rule, then Dennett has got to be wrong. And I really don't see how she can behave this way without representing the rule, without knowing what the rule is. She didn't just follow a rule, she acted to enforce a rule that she must have understood. I just don't see how that's possible without some sort of representation of the rule.
It would be tempting to say that there's a rule that dominant animals act in such-and-such a way under such-and-such circumstances, and that this does not require representing the rule and recognizing its normative character. But the problem with seeing it this way is that the circumstances required to follow this rule involve the failure of another dog to follow the rule. That requires some sort of representation of that rule as something the other dog should follow.
I don't know whether representing the rule is necessary for morality, but I don't see this as an insurmountable barrier to animals. The abilities that set us apart from other animals always seem more a matter of degree than of kind.