He said they had control groups where some of the foxes were selected for aggression and some weren't selected at all. I think he didn't explicitly mention it but presumably the traits associated with domestication didn't appear in the control groups. Interesting about the rabbits - but wouldn't there be less inbreeding if their numbers are huge? It could just be indicating that there's a relaxed selection, indicated by the huge numbers, and more of the variants survive. Could be those patchy ones are less aggressive?

@@hywelgriffiths5747 You are correct about Balyaev's foxes, the traits typical of our domesticated animals did not develop in the group that was selected for enhanced aggression, and you are also right about inbreeding being less likely to occur in larger populations, obviously.

No, these are two distinct types of aggression familiar even from domesticated species (dogs, for example - some dog breeders refer to reactive aggression as "defensive" aggression, but that does not mean it is benign, since it is not premeditated and can be very unpredictable), and they have different biochemical bases. (Breeders routinely breed out reactive aggression if only for their own safety, but also so their livestock will not kill each other.) That is why you can breed for or against one kind of aggression while not affecting the frequency of the other type at all. ADDENDUM: Having listened to more of his lecture, I would add that while the speaker would not say that proactive aggression is a form of reactive aggression (it is clearly different in a fundamental way), he IS saying that the curbing of reactive aggression in man is the evolutionary result of proactive aggression.

@@michaels4255 well, i'm not sure i'm buying that you can breed different types of aggression into dogs. pitbulls and dobermans are bred for opposite types of aggression, but the truth is that both are unpredictable and both display both types of aggression. i would need somebody to actually identify the genes (or even the hormones) before i took the idea of a biochemical difference seriously, even if the practice is widespread. but, my point wasn't to question the definitional change being presented, it's to question if the change is illusory or not. another somewhat related example would be trying to separate between idealism and pragmatism, which i utterly reject. idealism is really just a type of pragmatism, in the sense that it's just a different attempt to reach an ends that is desirable to the person tactically making decisions. this idea of means v ends is just semantic gobbledygook, in the end - all there is is ends and different ways to justify those ends. likewise, proactive aggression is _always_ just a means to get ahead of reactive aggression, in the end. all aggression is self-defence; otherwise, it's an inefficient use of resources, and should be selected out for _that_ reason. so, yes - i know these are supposed to be two different ideas. but, i'm challenging whether they really are or not. think about it a little before you respond, if you choose to.