When should salespeople sell with facts and figures, and when should we try to speak to the buyer’s emotional subconscious, instead? When do you talk to Mr. Intuitive, and when to Mr. Rational?

I’d argue that too often, selling to Mr. Rational leads to analysis paralysis, especially for complex products or services. And yet many of us continue to market almost exclusively to Mr. Rational. The result is that we spend too much time chasing sales opportunities that eventually stall out. We need to improve our ability to sell to Mr. Intuitive.

We default to selling to Mr. Rational because when we think of ourselves, we identify with our conscious rational mind. We can’t imagine that serious executives would make decisions based on emotion, because we view our emotional decisions as irrational and irresponsible.

But what if Mr. Intuitive has a logic of his own? In recent years, psychologists and behavioral economists have shown that our emotional decisions are neither irrational nor irresponsible. In fact, we now understand that our unconscious decisions follow a logic of their own. They are based on a deeply empirical mental processing system that is capable of effortlessly processing millions of bits of data without getting overwhelmed. Our conscious mind, on the other hand, has a strict bottleneck, because it can only process three or four new pieces of information at a time due to the limitations of our working memory.

The Iowa Gambling Task study, for example, highlights how effective the emotional brain is at effortlessly figuring out the probability of success for maximum gain. Subjects were given an imaginary budget and four stacks of cards. The objective of the game was to win as much money as possible, and to do so, subjects were instructed to draw cards from any of the four decks.

The subjects were not aware that the decks were carefully prepared. Drawing from two of the decks led to consistent wins, while the other two had high payouts but carried oversized punishments. The logical choice was to avoid the dangerous decks, and after about 50 cards, people did stop drawing from the risky decks. It wasn’t until the 80th card, however, that people could explain why. Logic is slow.

But the researchers tracked the subjects’ anxiety and found that people started to become nervous when reaching for the risky deck after only drawing 10 cards. Intuition is fast.

Harvard Business School professor Gerald Zaltman says that 95% of our purchase decisions take place unconsciously – but why, then, are we not able to look back through our decision history, and find countless examples of emotional decisions? Because our conscious mind will always make up reasons to justify our unconscious decisions.

In a study of people who had had the left and right hemisphere of their brains severed in order to prevent future epileptic seizures, scientists were able to deliver a message to the right side of the brain to “Go to the water fountain down the hall and get a drink.” After seeing the message, the subject would get up and start to leave the room, and that’s when the scientist would deliver a message to the opposite, left side of the brain asking “Where are you going?” Now remember, the left side of the brain never saw the message about the fountain. But did the left brain admit it didn’t know the answer? No. Instead it shamelessly fabricated a rational reason, something like, “It’s cold in here. I’m going to get my jacket.”

So if you can’t reliably use your own decision-making history as a guide, when do you know you should be selling based on logic, or on emotion?

Here’s the short rule of thumb: sell to Mr. Rational for simple sales, and Mr. Intuitive for complex sales.

This conclusion is backed by a 2011 study based on subjects selecting the best used car from a selection of four cars. Each car was rated in four different categories (such as gas mileage). But one car clearly had the best attributes. In this “easy” situation with only four variables, the conscious deciders were 15% better at choosing the best car than the unconscious deciders. When the researchers made the decision more complex – ratcheting the number of variables up to 12 — unconscious deciders were 42% better than conscious deciders at selecting the best car. Many other studies have shown how our conscious minds become overloaded by too much information.

If you want to influence how a customer feels about your product, provide an experience that creates the desired emotion. One of the best ways for a customer to experience your complex product is by sharing a vivid customer story. Research has shown that stories can activate the region of the brain that processes sights, sounds, tastes, and movement. Contrast this approach to a salesperson delivering a data dump in the form of an 85-slide power point presentation.

Rather than thinking of the emotional mind as irrational, think of it this way: an emotion is simply the way the unconscious communicates its decision to the conscious mind.

Michael Harris is CEO of Insight Demand and author of Insight Selling.