Anyone who's ever seen a monkey at a zoo, or on tv knows that monkeys have a sense of humor disturbingly similar to that of boys age 3-30 or so. The similarities in behavioral genetics are so undeniable, it's hard to see how anyone could deny them. But now, science has gone quite a bit farther, and there's been quite a media buzz about it.
It's been suggested before that human laughter grew out of primate roots. But ape laughter doesn't sound like the human version. It may be rapid panting, or slower noisy breathing or a short series of grunts.
So what does that have to do with the human ha-ha?
To investigate that, Marina Davila Ross of the University of Portsmouth in England and colleagues carried out a detailed analysis of the sounds evoked by tickling three human babies and 21 orangutans, gorillas, chimps and bonobos.
After measuring 11 traits in the sound from each species, they mapped out how these sounds appeared to be related to each other. The result looked like a family tree. Significantly, that tree matched the way the species themselves are related, the scientists reported online Thursday in the journal Current Biology.
The article goes on to note work by Jaak Panksepp of Washington State University, which goes even farther:
Panksepp's own work concludes that even rats produce a version of laughter in response to play and tickling, with chirps too high-pitched for people to hear. So he believes laughter goes even farther back in the mammalian family tree than the new paper proposes.
And Kent Jones on Rachel Maddow Thursday goes even farther still: