HBS professor Gerald Zaltman says that 95% of consumers' purchase decision making takes place in the subconscious mind. If that's true, how can a marketer influence consumer choice? Zaltman explains his theory in a recent Q&A with Manda Mahoney of HBS's Working Knowledge.

One way, contends Zaltman, is to double check "stated beliefs" with "actual behavior." For instance, when a consumer says he or she compares brands and pricing, how does that stack up to his or her trip to the store? In many instances, consumers don't even look at alternatives to the chosen brand. Another approach: study the metaphors consumers use to express their particular thoughts and feelings about a product. This is most effectively done, Zaltman says, through one-on-one interviews with customers, which according many researchers, "are superior to focus groups."