The first thing that you need to understand about humans

Humans aren't rational -- they rationalize. And I don't just mean "some of them" or "other people". I'm talking about everyone. We have a "logic engine" in our brains, but for the most part, it's not the one in the driver's seat -- instead it operates after the fact, generating rationalizations and excuses for our behavior.

I first realized this fact several years ago when I read something about "split brain" people. These people have had their corpus collosum, the structure which connects the left and right brain hemispheres, cut or damaged, leaving the two halves of the brain largely unable to communicate with each other. I don't recall where I read that, but a quick Google turned up this similar article:

"A split-brain patient shown a photograph of Hitler only in the right hemisphere, for example, might exhibit facial expressions indicating anger or disgust. But when asked to explain those emotions, the patient will often invent an answer, such as 'I was thinking about a time when someone made me angry.'" (Newberg and D'Aquili 2001, p. 23)

Kenneth Heilman offers another, more concrete example, writing about the research of Dr. Michael Gazzaniga and his colleagues. In one experiment, they showed sexually suggestive pictures to a woman with callosal disconnection, flashing them only on the left half of a screen so only her right hemisphere could perceive them. The woman giggled and blushed, but when asked why she was doing so, she replied that she was thinking of something embarrassing (Heilman 2002, p. 129).

Are these people lying? In one sense of the word, perhaps; but it seems clear that there is no conscious intent to deceive. Rather, researchers have concluded, what is happening is that the right hemisphere, upon seeing an image with strong emotional connotations, generates the appropriate response. However, due to the callosal disconnection, it cannot transmit the associated sensory data to the left hemisphere and its language centers. The left hemisphere perceives a change in the body's state, but does not know why - and so it "fills in" the missing details, fabricating a logical reason for the emotional reaction. This happens at a subconscious level, so that the person genuinely believes the verbal explanation they provide. In the language of psychology, this filling-in process of unconscious invention is called confabulation.

The important realization is that this process of "confabulation" is not limited to people with brain damage -- everyone does it -- people with "split brain" are just a little more obvious.

It's tempting to think that "most people" have this problem, but that you or I are different, to think that our actions are all logical. That is a mistake -- denying the truth is irrational and dangerous. By accepting that people are fundamentally irrational, we can deal with ourselves and others in a more rational and effective manner. We can learn to manage our irrational selves (somewhat). If, however, we insist that all of our actions and feelings are rational, then we will never be able to deal with them honestly, and are more likely to cling to irrational beliefs and limitations. If we are going to be honest, then we must admit the possibility that everything we know and believe is, in fact, incorrect.

The fascinating (and easy to read) book "Influence: Science and Practice" has some great examples and explanations of how people actually work. Here's a great quote about the effect of attractiveness, and how unaware people are of their true decision making process:

A study of the 1974 Canadian federal elections found that attractive candidates received more than two and a half times as many votes as unattractive candidates (Efran & Patterson, 1976). Despite such evidence of favoritism toward handsome politicians, follow-up research demonstrated that voters did not realize their bias. In fact, 73 percent of Canadian voters surveyed denied in the strongest possible terms that their votes had been influenced by physical appearance; only 14 percent even allowed for the possibility of such influence (Efran & Patterson, 1976). Voters can deny the impact of attractiveness on electability all they want, but evidence has continued to confirm its troubling presence (Budesheim & DePaola, 1994).

A similar effect has been found in hiring situations. In one study, good grooming of applicants in a simulated employment interview accounted for more favorable hiring decisions than did job qualifications—this, even though the interviewers claimed that appearance played a small role in their choices (Mack & Rainey, 1990). The advantage given to attractive workers extends past hiring day to payday. Economists examining U.S. and Canadian samples have found that attractive individuals get paid an average of 12-14 percent more than their unattractive coworkers (Hammermesh & Biddle, 1994).

Equally unsettling research indicates that our judicial process is similarly susceptible to the influences of body dimensions and bone structure. It now appears that good looking people are likely to receive highly favorable treatment in the legal system (see Castellow, Wuensch, & Moore, 1991; and Downs & Lyons, 1990, for reviews). For example, in a Pennsylvania study (Stewart, 1980), researchers rated the physical attractiveness of 74 separate male defendants at the start of their criminal trials. When, much later, the researchers checked court records for the results of these cases, they found that the handsome men had received significantly lighter sentences. In fact, attractive defendants were twice as likely to avoid jail as unattractive defendants. In another study —- this one on the damages awarded in a staged negligence trial -- a defendant who was better looking than his victim was assessed an average amount of $5,623; but when the victim was more attractive of the two, the average compensation was $10,051. What's more, both male and female jurors exhibited the attractiveness-based favoritism (Kulka & Kessler, 1978).

Other experiments have demonstrated that attractive people are more likely to obtain help when in need (Benson, Karabenic, & Lerner, 1976) and are more persuasive in changing the opinions of an audience (Chaiken, 1979).

Understanding our irrational nature is also critical to product design. How can you expect to make something for humans if you don't understand how they think or make decisions?

Another book, "The Culture Code", has some great examples based on the author's experience helping companies improve the design and marketing of their products.

The people at Chrysler had indeed asked hundreds of questions; they just hadn't asked the right ones. They kept listening to what people said. This is always a mistake. As a result, they had theories about moving the Wrangler in multiple directions (more luxurious, more like a traditional car, without removable doors, enclosed rather than convertible, and so on) with no clear path to follow.
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When I put groups of consumers together, I asked them different questions. I didn't ask them what they wanted in a Jeep; I asked them to tell me about their earliest memories of Jeeps.
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I returned to those wary Chrysler executives and told them that the Code for Jeep in America is HORSE. Their notion of turning the Wrangler into just another SUV was ill advised.
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The executives weren't particularly moved. After all, they had vast research that told them consumers said they wanted something else. ... I asked them to test my theory by making a relatively minor adjustment to the car's design: replacing the square headlights with round ones. Why? Because horses have round eyes, not square ones.
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They tested the new design and the response was instantly positive. Wrangler sales rose and the new "face" of the Wrangler became its most prominent and marketable feature. In fact, the car's logo has incorporated its grille and round headlights ever since.

Using surveys and focus groups to design your product is a great way to produce boring and mediocre products that are the same as everything else.

Another great quote from "The Culture Code" connects us back to the "split brain" example that I started with:

What do Americans look for in a car? I've heard many answers when I've asked this question. The answers include excellent safety ratings, great gas mileage, handling, and cornering ability, among others. I don't believe any of these. That's because the first principle of the Culture Code is that the only effective way to understand what people truly mean is to ignore what they say. This is not to suggest that people intentionally lie or misrepresent themselves. What it means is that, when asked direct questions about their interests and preferences, people tend to give answers they believe the questioner wants to hear. Again, this is not because they intend to mislead. It is because people respond to these questions with their cortexes, the parts of their brains that control intelligence rather than emotion or instinct. They ponder a question, they process a question, and when they deliver an answer, it is the product of deliberation. They believe they are telling the truth. A lie detector would confirm this. In most cases, however, they aren't saying what they mean.

The reason for this is simple: most people don't know why they do the things they do. In a classic study, the nineteenth-century scientist Jean-Martin Charcot hypnotized a female patient, handed her an umbrella, and asked her to open it. After this, he slowly brought the woman out of her hypnotic state. When she came to, she was surprised by the object she held in her hand. Charcot then asked her why she was carrying an open umbrella indoors. The woman was utterly confused by the question. She of course had no idea of what she had been through and no memories of Charcot's instructions. Baffled, she looked at the ceiling. Then she looked back at Charcot and said, "It was raining."
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Even the most self-examining of us are rarely in close contact with our subconscious. ... Therefore, we give answers to questions that sound logical and are even what the questioner expected, but which don't reveal the unconscious forced that precondition our feelings. This is why polls and surveys are so often misleading and useless.

Of course this understanding is important to more than just product design. It's critical to anything involving humans, which is everything involving us. How does it apply to your life and work? Are you still making decisions with the assumption that we are rational?