Psychographic segmentation is an evolution of psychoanalysis; in particular Jaques Lacan, whose work in the 50s took the general ideas of Freudian psychoanalysis and applied them to larger phenomenon -- namely how language and symbolism can be used to pluck emotional strings and influence the minds of groups of like-minded people. An ad man in the 1950s would certainly have been aware of his work. The folks from CA have gone on record about the influence of Lacan, so it's not remotely a stretch.

Edit: For a reference, https://pdfs.semanticscholar.org/75bb/e8a5de1fef2b9da44ca1ed... (dense as heck, but imagine you're an ad man from the 50s when reading it)