Should Chimpanzees Have Moral Standing? An Interview with Frans de Waal

Liza Gross in PLoS Blogs:

Gross: What are some of the seminal experiments that revealed similarities in cognitive or behavioral traits between apes and humans, suggesting we’re not in fact unique, as many like to think?

ScreenHunter_01 Mar. 30 14.00De Waal: There are many. For example, tool use used to be considered uniquely human. And then when it was found in captivity by Köhler, this is in the 1920s, people would say, “Well, but at least in the wild they never do it.” And then it was found in the wild, and then they would say, “Well, at least they don’t make tools.” And then it was found that they actually also make tools.

So tool use was one of those dividing lines. Mirror self-recognition is a key experiment that was first conducted on the apes. The language experiments, even though we now doubt what the apes do is actually what we would call “language,” they certainly put a dent in that whole claim that symbolic communication is uniquely human.

My own studies on, let’s call it “politics,” and reconciliation behavior and pro-social behavior have put a dent in things. And so I think over the years every postulate of difference between humans and apes has been at least questioned, if not knocked over. As a result, we are now in a situation that most of the differences are considered gradual rather than qualitative.

And the same is true, let’s say, between a chimp and a monkey. There are many differences between chimps and monkeys in cognitive capacities, but we consider them mostly gradual differences.

The more we look at it, even if you take the difference between, let’s say, a human and a snake or a fish, yes, between those species the differences are very radical and huge, but even these species rely on some of the learning processes and reactions that we also know of in humans.

More here.