It turns out, if you believe the account on Snopes, which I gather is a usually reliable source, that the conventional account is not merely debatable, it is false—the result of deliberate fraud by one James Vicary. From Snopes:
" You see, Vicary lied about the results of his experiment. When he was challenged to repeat the test by the president of the Psychological Corporation,
"As numerous studies over the last few decades have demonstrated, subliminal advertising doesn't work; in fact, it never worked, and the whole premise was based on a lie from the very beginning. James Vicary's legacy was to ensure that a great many people will never be convinced otherwise, however."
What struck me as interesting about the account is that Vicary's fraud worked. I don't know what its long term effects were on his career, but the long term effect on our culture was to strengthen the idea that human beings are not all that rational, that what appears to be voluntary choice is often really due to fraud or coercion. Vicary's flashing messages provide a memorable and convincing argument against freedom of choice on the marketplace, and one that I see echoed in many arguments. And the fraud continues to work long after it was exposed.
For another, and perhaps more debatable, example of the same pattern, consider Margaret Mead's Coming of Age in Samoa. It was a very popular book, widely used in college courses. Part of its implicit message was that the traditional pattern of sexual behavior in our society was a mistake—an unnecessary and damaging repression of natural impulses, as demonstrated by the happy and sexually liberated youth of Samoa. While the changes in sexual behavior during the course of the 20th century surely had multiple causes, it's reasonable to view Mead's book as one of them.
Many years later, Derek Freeman, in Margaret Mead and Samoa: The Making and Unmaking of an Anthropological Myth, convincingly argued that Mead's entire account was bogus. Mead did not know the language when she arrived in Samoa, was not particularly skilled in languages, and it is at least debatable whether she ever became fluent. She did not live with the people she was studying but with an American family in the village. By Freeman's account, she was heavily dependent on what she was told by a couple of teenaged informants through a translator; he thinks they were deliberately misleading her in the direction of what she wanted to believe, for their own entertainment. And she made no attempt to check the available crime statistics, which would have shown that her peaceful paradise had high rates of murder and rape.
Freeman's book set off an extensive controversy, with some anthropologists accepting his view, others defending Mead. The most interesting response I saw was by a friend and ex-colleague of Mead, who accepted Freeman's factual claim and argued that what Mead was really doing was not research but the creation of a myth, and that the spreading of that myth in our culture had good, not bad, effects.
After reading some of the controversy I think Freeman is probably correct; I remain uncertain as to whether, if so, Mead was a victim of her informants, as Freeman suggests, or deliberately dishonest. But either way, however false her account of Samoa, the effect on Europe and America, good or bad, remains. Lies can succeed.