Chimps and bonobos may be missing a few of these elements, but they are doing better than the present generation of artificial-intelligence programs. Even in entities with all the elements, we would expect considerable variation in intelligence because of individual differences in processing speed, in perseverance, in implementing shortcuts and in finding the appropriate level of abstraction when using analogies.
Why are there not more species with such complex mental states? A little intelligence can be a dangerous thing. A beyond-the-apes intelligence must navigate between the twin hazards of dangerous innovation and a conservatism that ignores what the Red Queen explained to Alice in Through the Looking Glass: ...it takes all the running you can do, to keep in the same place. Foresight is our special form of running, essential for the intelligent stewardship that the late Stephen Jay Gould of Harvard University warned is needed for longer-term survival: We have become, by the power of a glorious evolutionary accident called intelligence, the stewards of lifes continuity on earth. We did not ask for this role, but we cannot abjure it. We may not be suited for it, but here we are.
WILLIAM H. CALVIN is a neurobiologist at the University of Washington. He studied physics at Northwestern University but made the transition to neuroscience at the Massachusetts Institute of Technology and Harvard Medical School. He received his Ph.D. in physiology and biophysics from the University of Washington in 1966. Calvin is also the author of several books on science for the general public. His literary efforts include The Throwing Madonna, The River That Flows Uphill, Conversations with Neils Brain, A Brain for All Seasons, A Brief History of the Mind and Almost Us. See www.williamcalvin.com