The participants' perception of schadenfreude laughter was especially interesting. It was heard as being dominant but not quite so dominant as taunting; senders who engaged in such laughter were judged as being in a positive state, more so than taunting but less than tickling. Schadenfreude laughter was heard as being neither aggressive nor friendly toward the receiver but as neutral. According to the authors, whose interpretations of these data again were inspired by evolutionary logic: “Schadenfreude laughter might therefore represent a precise (and socially tolerated) tool to dominate the listener without concurrently segregating him from group context.”
I would like to think I was witnessing pure, unadulterated joy in King those many years ago, but of course my brain isn't made to decipher distinct emotive states in gorillas. He has since been laughing, apparently, at Ellen DeGeneres while watching her on television in his cage; two is a small sample size, I realize, but perhaps he finds homosexual human beings particularly comical. In any event, it brings me joy to think of the evolution of joy. And I've got to say, those rat data have me seriously considering a return to my old vegetarianism days—not that I dine on rats, of course, but laughing animals do make the prospect of animal suffering unusually salient and uncomfortable in my mind.
If only dead pigs weren't so spectacularly delicious.