Most of us believe we are in control of the decisions we make and the picture of the world we form. Leonard Mlodinow argues that recent research in the field of neuroscience has shown this to be a myth. In Subliminal, Mlodinow demonstrates the enormous influence that our unconscious brain exerts over our everyday affairs.

There’s a revolution taking place in the field of neuroscience, one that’s been mushrooming since the early 2000s. It’s called social neuroscience. Just as quantum mechanics and the theory of relativity have replaced Newtonian physics, so recent breakthroughs in neuroscience are changing the way we understand human behavior.

While we humans like to think of ourselves as distinct from and superior to other animals, we—like fruit flies and tortoises—carry out many behaviors without any prior deliberation. We see the unconscious at play in the minutia of daily life. For example, without thinking about it, we instinctively stand closer to people we know than people we don’t when engaging in a conversation.

Sigmund Freud conducted experiments to explore the interconnections of the brain, but the available technology was not sophisticated enough to support his pursuits. He talked with his patients instead, but was unable to fully access the unconscious. As a result, Freud’s approach and theories were inaccurate.

Talk about the unconscious mind was highly speculative for decades, but thanks to technologies that can isolate the firings of single neurons, we can speak with greater accuracy about the unconscious mind without resorting to vagaries. To distinguish recent developments from more antiquated ideas about the unconscious, social neuroscientists talk about the resurgence of interest in this area as the “new unconscious.” This new unconscious is far less aggressive and incestuous than Freud’s version.

For years, the notion of the unconscious was rejected. The dominant assumption was that humans exerted conscious control over their actions and thoughts. The unconscious was relegated to the trash heap, perhaps in part because the idea that we are not in control of our lives and actions is unnerving. However, it appears that we really aren’t in control, and psychologists and economists are slowly—and in some cases begrudgingly—accepting this. This lack of control raises the question of what, then, is controlling us? The unconscious has returned to the discussion as the likely explanation.

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Some variation of the conscious-unconscious division can be seen as far back as ancient Greek philosophy. More recently, eighteenth-century philosopher Immanuel Kant made important contributions to the subject with his theories about perception. During the Enlightenment era, when rationality was held up as the ideal, Kant argued that we are hardly unbiased observers of the world around us who disinterestedly build a theory of everything. The mind, rather, implicitly builds a worldview based on its particular perceptions.

Kant, however, rejected the view that psychology could become a science; he believed it was impossible to empirically map out the brain’s inner workings. Fortunately, there were people who thought differently. In the early 1800s, E.H. Weber conducted experiments that showed how mental activity could be tested and expressed as mathematical and scientific laws. In 1879, German psychologist Wilhelm Wundt and American Harvard professor William James ran independent experiments on human behavior in informal labs. Their studies eventually won respect and repute and the field of psychology gained some recognition as a legitimate science. 

Thanks to the theories and experiments of Freud, Weber, Wundt, James, and others, psychology has become a well-recognized, fruitful field of study. Among other things, it has led to remarkable findings about the nature of the unconscious.

Psychology’s early pioneers laid important foundations for us to build upon and refine. William Carpenter’s theory of “two distinct trains of mental action,” for example, captured the unconscious-conscious distinction that subsequent generations of psychologists have continued to explore. One significant development is the growing consensus that the unconscious is the far more foundational and influential of the two trains of mental activity.

The unconscious helps us survive and enables us to make quick decisions that our conscious minds would belabor (think fight-or-flight). It interprets vast arrays of visual information seamlessly (over 30 percent of the brain’s energy is devoted to this). It also processes language and allows us to speak reflexively. Scientists now attribute 95 percent of cognitive operations to the unconscious. The unconscious also accounts for the majority of the energy that the brain consumes. Even if you play a rigorous, mentally-demanding chess match, the energy consumed by the parts of the brain that handle conscious cognitive tasks increases by a mere 1 percent.

Language is an amazing tool. The complexity of thought that we, as humans, are able to convey to others is unparalleled in the animal kingdom. Another layer of complexity is the non-verbal communication—a great deal is unconsciously communicated and understood at an emotional and social level. Even infants have this capacity. They can distinguish between anger and happiness in a person’s face without any prior tutorial or explanation. They will instinctively recoil from an angry face leering over the crib but respond happily to a facial expression that is gentle and sweet.

Another manifestation of our instinctive social nature is the way we naturally form support groups. Studies have shown that subjects who believed that they were about to endure painful electric shocks would group together when waiting for their name to be called, even when they had the option of choosing empty rooms. It seemed there was a sense of comfort and camaraderie derived from the presence of other people.

We are social creatures: to be deprived of the company of others for an extended period of time is painful. A study of almost 5,000 individuals found that people with more developed networks of close friends and family tended to live longer, healthier lives. After observing these subjects over the course of nine years, researchers found that those who were more isolated were twice as likely to die as those who were socially well-connected. This was the case even when the study was controlled for lifestyle habits like exercise, smoking, and alcohol.

There is also a demonstrable connection between social ability and intelligence. It is no coincidence that coordinated hunting efforts to bring down dangerous animals emerged at the same time as the earliest art and the observance of religious rites about 50,000 years ago. Culture sprang up when people began to socialize. Based on the remains that have been found, there were no physiological changes in our ancestors, which leads many to conclude that there must have been some change in the brain itself. Intelligence came about to accommodate a social purpose. Sociability increases the chances of survival.

Solomon Shereshevsky had the problem: he remembered everything, down to the minutest detail. While that might sound like a nice problem to have, he was unable to meaningfully integrate all the information, leaving him incapable of completing tasks that our brain is wired to complete automatically. For example, Solomon had a difficult time with facial recognition. If he saw the same person, it would likely be in a different setting, from a slightly different angle, and under different lighting; thus, it would register in his brain as a completely different face belonging to an entirely different person. If his memory of faces were a book, it would be a thick tome filled with photos with no table of contents or index to gather or group the various faces according to whom they belonged. What might have appeared a rare gift was also a curse because Solomon was unable to categorize.

Categorization is another function of the unconscious mind. It helps us navigate situations with greater ease and efficiency. This is a vital task because if it were up to our conscious brain to deal with the deluge of information we are constantly receiving, we would mentally short circuit. We wouldn’t be able to process it fast enough and make good decisions. 

At best, categorization makes differences more pronounced so that we keep the information necessary for survival. At worst, categorization can lead us to perpetuate stereotypes.

One of the earliest uses of the word “stereotype” comes from a book written by Walter Lipmann in 1922, in which he argued that our society is becoming too complex and transient. He suggested that simpler models are needed to make sense of—and function within—our cultural surroundings. Lipmann understood that stereotypes serve an important role and that our culture reinforces them.

But how accurate are these categories that we internalize? We generally base our judgments of others on their individual characteristics, but if we have an encounter with a stranger, we tend to fall back on our preconceived notions based on the person’s gender, ethnicity, style, manner of speech, and so on. Just as the unconscious brain fills in the gaps in our vision, hearing, and memory to make our picture of the world more seamless, so the unconscious fills in the social gaps where information is limited.

Scientists used to consider stereotyping a deliberate, conscious act, but the growing consensus is that stereotyping is an unconscious process, a natural outcome of the brain’s desire for categories. Numerous studies have revealed the unwitting biases of their subjects. Subjects are drawn to certain types of people over others and use differing sets of adjectives to describe people from diverse backgrounds. Participants tend to favor men over women and whites over blacks. On the occasions that researchers point out these discrepancies, subjects often respond with shock, anger, and embarrassment. 

Despite unfortunate events that have their roots in stereotypes, it is best not to throw out the baby with the bathwater. The brain’s ability to categorize is an important tool. The goal is not to stop categorizing—that’s a goal that’s doomed to failure. The goal should be to operate with the acknowledgement that we’re wired that way, and that we must consciously choose to view people as individuals and be aware of the ways in which our personal stereotype could impede that end.

Stereotypes are often used in the absence of concrete experiences with people or places we are not familiar with. Getting to know people from communities we are leery or dismissive of is an excellent way to correct our unconscious biases.

Just as our unconscious naturally categorizes others, it also categorizes us. We unconsciously put ourselves in out-groups and in-groups: those to whom we do or do not belong. This also has a tremendous impact on the way we view ourselves and others. The groups with which we do and don’t identify with help us construct a sense of identity. We alternate between various roles and groups according to the needs of the moment and for the purpose of maximizing happiness. Someone might conceive of herself as a woman, a student, a sister, a mother, a Korean, or a swimmer as each moment requires.

An example of a company that does a masterful job of cultivating an in-group that people are dying to be part of is Apple, particularly with their Mac computers. Apple spends millions to promote the image that the people who use their products are members of a cool, trendy in-group—and that PC users are the out-group losers who can’t quite keep up.

Studies reveal that we tend to have an affinity for those in our in-groups. Even if we highly esteem people from other out-groups, we do not care for them in the same way. We are more likely to overlook the shortcomings of others if they’re part of an in-group. We tolerate idiosyncrasies and mistakes from in-group members that we would likely judge harshly if displayed in an out-group member. We tend to primarily associate with and do business with in-group members, and we tend to give them the benefit of the doubt.

Game theory experiments consistently demonstrate our obsession with differentiating ourselves from others.  We want to feel different than (and superior to) others, even if it isn’t beneficial for us or others and when the distinction between us and them is superficial and arbitrary.

The us-them mentality goes back to our tribal hunter-gatherer ancestors. The most effective us-them barrier breaker is finding a purpose that is greater than the in-group/out-group issues to unite everyone. The 9/11 terrorist attacks provide an excellent example. As soon as the World Trade Center towers were hit, there was an impulse among people to rally together and help each other, regardless of religious or ethnic background. People were people, and the niceties of group dynamics seemed trivial compared to the overwhelming need that everyone was rushing to meet. In the days and weeks following the attacks, people in the city were not first and foremost black or white, religious or secular, rich or poor, but New Yorkers.

There was a survey done of nearly one million high school seniors. Of the students surveyed, 100 percent considered themselves at least average in their capacity for getting along well with others people, 60 percent considered themselves in the top 10 percent, and 25 percent considered themselves in the top 1 percentile. Everyone was convinced that they were winners—or at least not losers. This phenomenon is not unique to adolescents.

We can clearly see an over-inflated view of self in others, but can we recognize the same tendency in ourselves?

As one psychologist observed, we take one of two paths to truth: that of the scientist who gathers evidence and forms a conclusion based on the data, and that of the lawyer who has already reached a conclusion and works to reject opposing evidence and acquire new data that supports his conclusion. Our conscious mind can weight facts dispassionately, but the unconscious has beliefs that it insists on maintaining. The self is often caught between the pull of the lawyer and the scientist, but is also unaware of the lawyer’s influence on conclusions and decision-making.

Despite our best attempts to arrive at an objective, rational view of self and the world around us, the more emotional, strident voice usually emerges victorious. The brain is a good scientist, but a phenomenal lawyer. The term that some psychologists have landed on to describe this phenomenon is “motivated reason.” This motivated reason helps preserve our positive self-regard.

There are limits to this motivated reason, however. Sometimes our unconscious mind’s interpretation of an experience is so far-fetched or unconvincing that the conscious mind steps in and refutes it. This effectively halts the unconscious mind’s campaign to preserve particular beliefs via self-deception. Some inconsistencies are too glaring for even our unconscious to paper over.