The decline of the rational appeal

Saw this NYT op-ed (June 4): "Is Persuasion Dead?" by Matt Miller (hat tip: SPUG Forum), which got me thinking. Let's begin with the definition. The entry on dictionary.com says:

per·suade (tr.v.): To induce to undertake a course of action or embrace a point of view by means of argument, reasoning, or entreaty: "to make children fit to live in a society by persuading them to learn and accept its codes" (Alan W. Watts). See Usage Note at convince.

According to the Usage Note on convince, the traditional rule is that one persuades someone to act but convinces someone of the truth of a statement or proposition. This distinction, however, is loosing ground today.

In any case, the salient point is nicely captured by the dictionary.com definition: "by means of argument, reasoning, or entreaty"--in other words, a cognitive element is involved. Miller's thesis can thus be rephrased the death of the rational appeal. In the meantime, people--advertisers, politicians, whatnot--still need to get our assent on various things, still need to induce us to act in various ways more so than ever. They do so increasing by use of the sub-rational/non-rational appeals.

This reminds me of something I read in Neil Postman's Amusing Ourselves to Death about the decline of the rational appeal in advertising over the past two and a half centuries:

(An advertisement in the Boston Gazette, 1768 read:)

Whereas many person are so unfortunate as to lose their fore-Teech by Accident, and otherways, to their great Detriment, not only in Looks, but Speaking both in Public and Private:--This is to inform all such, that they may have them re-placed with false Ones, that look as well as the Natural, and Answers the End of Speaking to all Intents, by Paul revere, Goldsmith, near the Head of Dr. Clark's Wharf, Boston.

...

In the 1890's advertisers adopted the technique of using slogans...(for example) "You press the button; we do the rest"... At about the same time, jingles started to be used. In 1892, Procter and Gamble invited the public to submit rhymes to advertise Ivory Soap. In 1896, H-O employed, for the first time, a picture of a baby in a high chair, the bowl of cereal before him, his spoon in hand, his face estatic. By the turn of the century, advertisers no longer assumed rationality on the part of their potential customers. Advertising became one part depth psychology, one part aesthetic theory... (emphasis mine; Postman, 59-60)