the skeleton key to people’s brains

I’m reading Freud on Madison Avenue by Lawrence R. Samuel.  It is an interesting, not-too-dry history of depth psychology and motivational research in advertising.  This is something I’ve long been fascinated with- the use of psychology in ads (at it’s height in the 1950s and 60s?), but I’ve never before come across a book devoted to it exclusively.

There was a phrase I liked in the introduction.  Samuel writes of (the common perception that) admen possessed “the skeleton key to people’s brains.”  The image this creates in my brain is striking.  I picture something graphic, black and white: a white head and an ornate black key.  Maybe it’s just that skeleton key is such a great expression I would like it any way it was used.  But mixed with 50s paranoia it’s phenomenal.