yes, I always find defining by the negative to be a hysterical
  thing. If someone says, "God does not exist", one must first
  have a God, then have it not exist.

  There is a trick used in Marketing very frequently. Look for it
  and you'll spot it, I'll give an example:

  When cigarette manufacturers had to make signs saying that it's
  against the law for adults to buy cigarettes for people under
  the age of 18, they were very clever about their campaign.

  A known fact in advertising is that the "negative" is _very
  very_ weak psychologically: If I tell you, "DON'T THINK OF A
  PINK ELEPHANT DANCING ON TOP OF A WHITE GRAND PIANO FALLING INTO
  A VOLCANO"... you first have to first *think* about it... then
  push THAT out of your mind.

  I knew this from Anthony Robbins tapes from the 1990s. [his
  brand of neurolinguistic programming but it's basic advertsiing
  psychology.. which is often ahead of scientific psychology
  because it's directly financially motivated].

  What the cigarette manufacturers said were things along these
  lines:

  DON'T BUY CIGARETTES FOR MINORS.

  They had "don't" off to the left and "buy cigarettes" and "for
  minors" were indented perfectly lined up under head other, so
  that at first glance it reads:

  BUY CIGARETTES
  FOR MINORS

  and it's only AFTERWARDS, about 400ms afterwards - almost a
  whole 1/2 of a second, that we notice the "don't" and try to
  incorporate it.

  There were many variations of that, but the basic idea is well
  known.

  I love this kind of stuff and it's easy to find examples
  everywhere. Maybe not all are engineered reverse psychology but
  considering the amount of money they pour into ad campaigns -
  whatever the business or campaign is ["they" means anybody
  trying to promote something - not limiting to tobbacco companies
  - or even to companies. Works equally well anywhere] - I imagine
  it's used on a conscience level at least somewhat. Certainly by
  tobacco companies, who had some brilliant people working for
  them. I knew a couple of them when I worked for Schering-Plough
  - ex-Phillip Morris employees would jump over to Pharma because
  the corporate structures were similar and they're really in
  similar businesses. [controlled products for public
  consumption].

  Brilliant brilliant people.