Is an extra reward system why homo evolved extraordinary smarts?

(Another shower-stall moment.)

I surfed the science abstracts the other day on the topic of amphetamines (speed) and how they affect learning , memory and cognition in general. (Comes up because amphetamines make ADD kids better students and as contraband they're being called "smart pills"). The findings are a mess--is my tentative conclusion--and that's sort of to be expected given that the way to test intelligence is anybody's guess and that permission to drug healthy people is hard to get. In lieu of such subjects the reports tell us what happens when you give speed to schizophrenics, substance abusers, brain lesion victims and people with sleep disorders, plus a Noah's Ark of animals: Rats, chickens, horses, monkeys, fish...the list may go on a lot longer for all I know. Rats win the most attention hands down, of course. Anyway, I found a 1987 paper that matter-of-factly states by way of introduction (with reference to a string of citations) that the effect of speed on these species was zip, at least with regard to increasing a couple kinds of sharpness tested. So non-human animals seem to become no smarter on speed...traditionally...maybe. Yet all kinds of smartening emerges when you give speed to people--that is, to human beings who, while not "normal and healthy" in every test reported to a science journal, nevertheless may not be sick or weird in anyway that matters to the question at hand...far as I know, at least. Might this mean the human animal is special with regard to smarts? You know we'd like to think so.

Maybe what makes us special is an extra "reward circuit" in our brains. The characteristic addictiveness of speed and other stimulants gets pinned on dopamine and its action in the so-called "pleasure" or "reward" center of the brain. Maybe what distinguished early homo was that a banana or any other stimulus outside the skull was not all our ancestral brains could look to for reinforcing (ala Pavlov) a behavior or way of cogitating. What if a mutation sent some nerve astray during development in utero or postnatally and created a new input into the reward center? It was bound to happen, in fact, and what if on a particular occasion the stray originated from an area with great acoustics for what was going on overall in the brain. What if this line got livelier when several circuits resonated and such resonance signaled mental concepts cohering? That homo would get an internal reward--a splash of dopamine--every time she put two and two together. That is, she'd get the splash even if her immediate surroundings offered her no application for her insight. In particular, notice that pairing "two and two" would reward her, while not "two and three," say, because combination like that don't harmonize. To an individual of such an evolutionary lineage, suddenly logical coherence (cognitive resonance?) is its own reward.

Notice also that if you can receive a reward on the road, you become able to plan. Perhaps it would be wise to bring a stick or something club-like to the banana grove this time? It's easy to imagine that being able to plan even a little more elaborately could broaden a lot the spectrum of things that become easier with thought. So any homo with even a slightly bigger brain might be sure to compete more effectively and produce more progeny than the others, and our line would be on its way to a bigger and fancier brain. Meanwhile pongo (chimps) deriving no pleasure from a good proof are monopolizing mates each time mostly with such variations as super lustrous hair. Passing pongo homo can only remark "Too bad about the brain, but may I say what a fine coat you've got? Did someone just turn down the heat? Crap. I better come up with something quick."

The rest is history.

Note I don't imagine a just-so story like this one wholly displacing others that have been floated famously: Like that we surged toward fancier brains when we evolved the capacity for subtle vocalizing and/or invented language. But I find it uniquely pleasing. It explains the evolution of our ancestors into ourselves by a way of a process that seems contemporary and so might persist to this day. It also seems morally superior. Any lineage could have emerged smarter by flapping its lips. But maybe we got this way because we like to learn and choose to do so. Ever wondered why so many species can learn to act so smartly after you toss them a few biscuits or bananas or fish, but won't write so much as a novella if left to themselves?