Businesses have long been cognizant of the 80/20 rule that describes many phenomena faced by management (for example, 20% of your customers account for 80% of sales). But as companies try to refine their marketing strategies, they’re beginning to focus on the 10% of influential “apostle” customers who really drive sales through word-of-mouth recommendations to their friends. “The identification and ‘employment’ of a relatively small number of these customers on behalf of a product or service can greatly improve both the efficiency and effectiveness of a marketing strategy,” says author Jim Heskett. But that strategy can be even further refined, according to Gerald Zaltman, author of a new book called “How Customers Think: Essential Insights into the Mind of the Market.” Zaltman recommends mining the subconscious—what he calls the mind/brain—where 95% of our thinking takes place. By conducting relatively small numbers of in-depth individual interviews to specially selected customers, insights on how best to position and promote a product can be gained, while at the same time reining in costs. “All of this suggests that what we experience as consumers may be influenced by fewer and fewer ‘voices’ from the market,” says Heskett. “The promise is that we will like what we experience, because it will involve such things as fewer irrelevant messages, better availability of products and services, and product performance geared to our needs.” However, Heskett cautions that while the strategy is certainly appealing after years of wasted marketing dollars, it may backfire by limiting too narrowly the opportunities for consumer feedback.