Second, I suppose we could end up at optimal designs for what we wanted through iterative A/B testing. Given enough time, enough variations, and enough traffic, you could conceivably come to the ideal webpage for conversion (of whatever metric you wanted). Of course, as people change, the page would have to change as well. The Gladwell article posted earlier today is a good companion read to this piece, I thought.
I'm not certain if this was a premeditated design choice, but it actually played out very nicely.
For example, mother turkeys, who are known to be caring parents (as far as birds go), tend to respond only to the "cheep-cheep" sound of their chicks.
"Hearing the cheep-cheep, the mother turkey coddles and cares for the young turkey chick. It is a short-cut response that nature has given turkeys to know how to behave. It tends to work well in nature. But, tricky scientists recorded the cheep-cheep sound and placed the recording into a stuffed Polecat, the natural enemy of the turkey, and found that the mother turkeys adopted the stuffed polecat. Coddled it and cared for it."
* Chomsky - Language and Responsibility - p52
Incidentally, that's why I never liked ball games.
[edit: Wiesel, not Weisel]
(cue pun about "duck typing")
I think you are right that this has implications for a lot of things, not least graphic design. If you have a good grasp of how people respond to different elements you could guide their actions even more than now.
I first learned about the research from a brief footnote in the book Phantoms in the Brain by V.S. Ramachandran (highly recommended). Then I spent quite a long time looking for the article sourced, by Tinbergen, which is:
Tinbergen N., and Perdeck, A.C. (1950). On the stimulus situation releasing the begging response in the newly hatched Herring Gull chick (Larus Argentatus argentalus Pont). Behavior 3:1-39
Took me forever to track this article down, so if you want a copy, ping me.
Also, it's copyrighted so I figured linking to it might be morally dubious.