Diep inzicht van wat mensen beweegt is niet van recente datum. In 1876 publiceerde Mark Twain’s The adventures of Tom Sawyer. Tom, een jongen met veel fantasie, wordt in het begin van het boek betrokken bij een vechtpartij. Voor straf moet hij het hek rond het huis schilderen. Al snel wordt duidelijk dat Tom heel goed door heeft wat mensen beweegt…

“Hi-yi! You’re up a stump, ain’t you!”twain-tom-sawyer
No answer. Tom surveyed his last touch with the eye of an artist; then he gave his brush another gentle sweep and surveyed the result, as before. Ben ranged up alongside of him. Tom’s mouth watered for the apple, but he stuck to his work. Ben said: “Hello, old chap, you got to work, hey?
Tom wheeled suddenly and said:
“Why it’s you Ben! I warn’t noticing.”
“Say––I’m going in a swimming, I am. Don’t you wish you could?
But of course you’d druther work––wouldn’t you? Course you would!”
Tom contemplated the boy a bit, and said:
“What do you call work?”
“Why ain’t that work?”
Tom resumed his whitewashing, and answered carelessly:

“Well, maybe it is, and maybe it ain’t. All I know, is, it suits Tom Sawyer.”

“Oh come, now, you don’t mean to let on that you like it?”
The brush continued to move.
“Like it? Well I don’t see why I oughtn’t to like it. Does a boy get a chance to whitewash a fence every day?”
That put the thing in a new light. Ben stopped nibbling his apple. Tom swept his brush daintily back and forth––stepped back to note the effect––added a touch here and there––criticised the effect again––Ben watching every move and getting more and more interested, more and more absorbed. Presently he said:
“Say, Tom, let me whitewash a little.
Tom considered, was about to consent; but he altered his mind:
“No––no––I reckon it wouldn’t hardly do, Ben. You see, Aunt Polly’s awful particular about this fence––right here on the street, you know––but if it was the back fence I wouldn’t mind and she wouldn’t. Yes, she’s awful particular about this fence; it’s got to be done very careful; I reckon there ain’t one boy in a thousand, maybe two thousand, that can do it the way it’s got to be done.”
“No––is that so? Oh come, now––lemme just try. Only just a little––I’d let you, if you was me, Tom.”
“Ben, I’d like to, honest injun; but Aunt Polly––well Jim wanted to do it, but she wouldn’t let him; Sid wanted to do it, and she wouldn’t let Sid. Now don’t you see how I’m fixed? If you was to tackle this fence and anything was to happen to it––”
“Oh, shucks, I’ll be just as careful. Now lemme try. Say––I’ll give you the core of my apple.”
“Well, here––. No, Ben, now don’t. I’m afeard––”
“I’ll give you all of it!”
Tom gave up the brush with reluctance in his face but alacrity in his heart.
Tom said to himself that it was not such a hollow world, after all. He had discovered a great law of human action, without knowing it — namely, that in order to make a man or a boy covet a thing, it is only necessary to make the thing difficult to attain.

MARK TWAIN(Mark Twain, The adventures of Tom Sawyer, 1876 p.20-22)

Je kunt het boek op internet overal vinden. Bijvoorbeeld hier: http://etext.lib.virginia.edu/toc/modeng/public/Twa2Tom.html