As a philosopher of mind, I have often imagined myself in exotic surroundings, engaged in one fantastic thought experiment or another--stranded on Mars or living as a brain in a vat or attempting to decipher the alien tongue of apparently intelligent creatures--but in June 1983 I had an opportunity to set aside thought experiments in favor of real experiments designed to explore the minds--and "language"--of some real alien creatures: vervet monkeys, living not in lab cages or enclosures but fending for themselves against a daunting array of predators in the beautiful, dangerous world of the East African savannah.
What makes vervet monkeys particularly interesting to a philosopher--or to anyone interested in the origins of human language and consciousness--is that they have the rudiments of a language, which serves them well in circumstances that must be quite similar to the world our ancestors faced at the dawn of human language and culture. Vervets have a variety of different vocalizations--calls and grunts--which seem to have clearly definable meanings. The most obvious (to an alien observer) are the alarm calls: one for snakes, another for eagles, a third for leopards, and each call evokes its own distinct and appropriate sort of behavior--for instance, scanning the sky and heading for cover in response to the eagle alarm. These might have been nothing more than instinctual cries, of course, no more like real, versatile human language than the famous dance of the honeybee, or the alarm calls of birds, but there is some tantalizing evidence suggesting that something more is going on with these monkeys. Unlike the birds and the bees, vervets seem to be engaged in a practice that could involve learning, insincerity, trustworthiness, deception, divided loyalty. While it would be wildly romantic to suppose that a vervet could tell a joke, it is not so clear that there isn't room in their way of life for one to tell a lie.
For instance, two bands or groups of vervets were once observed in a territorial skirmish; one group was losing ground and one of the losing-side monkeys, temporarily out of the fray, seemed to get a bright idea: it suddenly issued a leopard-alarm (in the absence of any leopards), leading all the vervets to head for the trees--creating a truce and regaining the ground his side has been losing. Does this anecdote reveal real cleverness and versatility among the speakers of Vervetese or was it just a coincidence or a bit of dumb luck for the losing-side monkeys--or a case of over-eager interpretation on the part of the observers? Could further observation--or better experiments--shed light on these questions? This is what I had come to Kenya to investigate.
(The whole paper is now available in Daniel Dennett, Brainchildren, Essays on Designing Minds, MIT Press and Penguin, 1998.)