If I were to suggest that almost every conversation you have about brands is influenced by the thinking of a Viennese psychologist, you'd probably think I was talking about Sigmund Freud. You'd be almost right, but not quite. Actually, I'm referring to the man who was sometimes known as the 'Sigmund Freud of the supermarket age' - a certain Ernest Dichter.

Ernest Dichter was one of the many extraordinary individuals who escaped Nazi Germany and went on to change postwar culture. Arriving in America in 1938, Dichter became part of what was known as the Motivation Research movement, which flourished in the 1940s and 1950s. The research techniques Dichter pioneered, and we are so familiar with today - including focus groups and depths - were developed to understand why people were attracted to certain products and lifestyle choices.

In just a few years, Dichter turned his research expertise into a global business, first by setting up the Institute of Motivational Research and then by launching Ernest Dichter Associates International. He worked for major American corporations, big food brands (Cadbury and Nestlé, for example), international airline brands such as Air France and Japan Airlines, and he conducted research for major advertising agencies including J. Walter Thompson, Young & Rubicam and McCann Erickson. In his Handbook of Consumer Motivations (1964), Dichter explained why he was so sought after by marketers and agencies: "In modern communication we have to penetrate to the deeper meaning which products, services, and objects that surround us have for the individual. Only by this deep insight can we truly be creative and communicate effectively." While Dichter wasn't the first researcher or the only advertising person to talk about unconscious desires or the symbolic significance of products and brands, he was definitely one of the best, ever, at it.

Perhaps, then, it is hardly a surprise that some of his work has had such a long shelf-life. Consider his work for Chrysler, for example. Dichter was the first to identify that convertibles were seen as symbols of youth and freedom and could influence perceptions of a brand, even among the 98% of consumers who would never consider actually buying a convertible. Today's car marketers are still following this advice, even though they don't know that it was Dichter who first gave it.

Back in the 1950s and 1960s, no business consultant was better known or more influential, and yet today Dichter is rarely read and even less frequently referred to. He has disappeared. So, what happened?

What happened was that the social critic and author Vance Packard got his teeth and his considerable flair for publicity into Dichter - the man he called "the most feared of the depth probers". In the preface to his global bestseller The Hidden Persuaders, first published in 1957, Packard warned readers that "the kind of tomorrow we may be tending toward ... may be exemplified by the depth probing of little girls to discover their vulnerability to advertising messages. No one, literally no one, evidently is to be spared from the all-seeing, Big Brotherish eye of the motivational analyst."

Remember this was in the late 1950s and early 1960s - a period of Cold War anxiety and paranoia when public opinion expressed a great deal of fear about the vulnerability of citizens and consumers and the ethical dilemmas involved in the rise of governmental and commercial propaganda - so Packard's critique fell on the opposite of deafears. In such a climate, Dichter and his associates came under intense scrutiny, got caught up in the hoo-ha about subliminal advertising and became somewhat tarnished.

However, while the man may have disappeared, his deeper meanings persist, sometimes to the bewilderment of those who debate them. As a client of mine once said to me in a brainstorming session about defining his brand: "Why does it have to have a meaning? Can't it just work?" And it doesn't take very long for any conversation about any brand to become a conversation about the kind of deeper meanings Dichter was so good at unearthing. Drinking a Coke really means drinking happiness; using Persil shows that you know there's a good side to dirt; and Snickers is more than just a nutty snack - it helps you feel more like yourself again. The deeper meanings of brands are a central part of what academics would call our industry's 'discourse'.

So, while Dichter's influence has waned, his way of thinking about products and brands tenaciously persists. Maybe this is exactly what Vance Packard was so worried about.