How old is the laugh? Well, it’s a funny story...

We’ve been trying to unlock the laugh for over half a century, and we’re finally forming some idea of where it comes from. “It is immediately clear and engaging and this is why it is still active.” Bubbling up The first truly human laugh may have emerged only about two million years ago, when early hominids developed the ability to wilfully control facial motor systems. It is from this point on that the “dark side” of laughter, unique to humans, emerged, say researchers from Binghamton University, in a 2005 study published in the Quarterly Review of Biology. “Humans can now voluntarily access the laughter program and utilise it for their own ends, including smoothing conversational interaction, appeasing others, inducing favourable stances in them, or downright laughing at people that are not liked,” the Binghamton biologists Matthew Gervais and David Sloan Wilson noted, in a statement. “Some scholars have suggested that this kind of vocal behaviour is shared across many animals who play, and as such, laughter is our human version of an evolutionarily old vocal play signal.” Rats, reportedly, “laugh” quite a lot.