Book Review — Subliminal: How Your Unconscious Mind Rules Your Behavior

A couple of months ago I was offered a review copy of Subliminal: How Your Unconscious Mind Rules Your Behavior, by Leonard Mlodinow. I don’t know that I’ve ever turned down a free book and based on the title I thought I would enjoy this one. I finally had a chance to read it and wanted to share some thoughts.

The short version is I enjoyed the book and recommend it to anyone with interest in how the mind works and how our unconscious influences our lives. You can find the book at Random House, Amazon, and Barnes & Noble. For the longer version of the review, read on.

The Book: An Overview

This isn’t a book about design, though it is a book about something I think most designers would be better for knowing. The general idea is right there in the title. It’s a look at how people experience the world and how perceptions, behaviors, memory, and social judgements are driven more by our unconscious minds than our conscious minds.

Much of what we communicate as designers happens on the unconscious level. Other than fellow designers it’s highly unlikely anyone is going to show up on your site and think “Oh look, there’s an 8 column grid in place. Clearly this site is telling me how organized it is.” Instead it’s their unconscious that takes in the grid and the person feels a sense of organization.

Book cover for Subliminal: How Your Unconscious Mind Rules Your Behavior, by Leonard Mlodinow

Similarly people don’t see a blue background and then consciously acknowledge they can trust the site or see a red button and make the conscious decision to impulsively click it.

Much of what we communicate as web designers talks directly to the unconscious mind so it makes sense for us to understand a little about how this part of the brain works.

The book is divided into 2 main sections

  • The Two-Tiered Brain — distinguishes the conscious from the unconscious and explores how the latter contributes to perception, memory, and the important role being social plays in the survival of humanity.
  • The Social Unconscious — looks at how much we communicate though non-verbal cues and then judge others based on those cues. It considers the importance of categorization and how we favor some categories over others. Finally it looks at how physical reactions lead emotional responses and how all of this affects our view of ourselves.

In walking through each of these subjects the book offers a number of case studies and experiments in psychology and some interesting stories illustrating the points it attempts to make.

To offer you a little more allow me to provide an expanded table of contents with a few highlights from each chapter.

The Two-Tiered Brain

This first section of the book has 4 chapters, which focus on how our brain works.

a lot of what we do as designers will go unnoticed, but will be communicated subliminally to the unconscious.

The New Unconscious — distinguishes the conscious and unconscious parts of the brain and shows how much we’re controlled by the unconscious part. Most significantly it shows how little we realize the role our unconscious plays.

Two experiments in this chapter should be of special interest to designers. One involved more readable and legible typography as enough to rate recipes better. Another involved packaging and copy leading to an improved taste of beer and wine.

Senses Plus Mind Equals Reality — investigates visual perception. It looks at how much we see without realizing we see it. One of the more interesting stories was about a stroke victim who’s eyes were physically fine, but his brain couldn’t process the signal they were sending. He was blind.

Yet this blind man could walk down the hallway of his hospital and despite the fact that his conscious mind couldn’t see, his unconscious mind could. This blind man was able to move out of the way of objects in his path without ever being aware he was seeing them.

Remembering and Forgetting — examines how we fill in the gaps of our memory and how the made up details eventually become the memory. In one of the more surprising experiments, an interviewer was switched in the middle of an interview and still most of the subjects couldn’t remember that this had occurred.

If you think you remember your life, read this chapter. You may discover much of your memory might be less real and more imagined than you think.

The Importance of Being Social — suggests that social action is the driving force behind human intelligence. It further suggests that social cooperation was most vital for survival of our species and so our brains have evolved for this purpose.

The chapter tells us that many species on the planet are self aware to some degree. However only human beings can go beyond believing something about themselves is true. We can also hold beliefs about the state of mind of others and reason about what one person thinks of another.

The Social Unconscious

The 6 chapters in this second section of the book look more at how we get along in the world. After seeing how much our unconscious rules our lives, how does it affect our interactions with each other, ourselves, and the world around us.

Reading People — looks at the non-verbal cues we all use when communicating and how we reveal much more than we say. Even more it suggests we’re seldom aware of how much we communicate through these non-verbal cues.

Judging People by Their Covers — discusses how the sound of someone’s voice or a light touch during conversation can influence how we perceive the message being delivered. One of the case studies in the chapter is the Kennedy/Nixon debates leading up to the 1960 Presidential election. Viewers who watched the debate thought Kennedy won, while those who only listened thought Nixon won.

Sorting People and Things — tells us that to process information more efficiently our brains rely on categorization strategies. It also suggests that without this ability to categorize we have difficulty making sense our our world.

In-Groups and Out-Groups — shows how after categorizing things and people into in-groups and out-groups we favor those groups we feel we’re a part of over groups we don’t feel a part of. The marketing lesson is to make your products part of your customer’s in-group.

Feelings — deals with things like the placebo effect. It shows how our physical well-being often leads emotional responses instead of the other way around. We don’t tremble because we’re angry. Rather we’re aware of feeling angry because we tremble. Or are we? Do we sometimes mistake feeling an emotion because of how we’re feeling physically?

The chapter suggests we can sometimes think we’re feeling something we aren’t due to some physiological change inside us and how we understand our feelings less than we think. In fact we sometimes rationalize our feelings in order to understand them.

Self — suggests that we believe in enhanced versions of ourselves instead of our true selves. In an interesting questionnaire 25% of people believe themselves to be in the top 1%, 60% believe themselves in the top 10%, and 100% of people believe themselves to be at least average.

We believe in facts that back our beliefs more than because the facts are true and we do this in order to improve our happiness. This chapter considers two ways i which we attempt to get at the truth.

  • scientists — gather evidence, look for patterns, form theories to explain observations, and then test those theories.
  • lawyers — begin with conclusions they want to convince others about and then seek evidence to support those conclusions, while discrediting evidence that doesn’t support them.

The chapter shows we’re better at being lawyers than scientists and favor things that support our preconceived beliefs.


Again this book won’t offer direct principles to follow, however, all designers should understand how the mind works. Knowledge of psychology, perception, and the unconscious are topics we should be aware of.

The unconscious rules much of what we take in and much of what we do. This suggests that a lot of what we do as designers will go unnoticed consciously, but will still be communicated subliminally to the unconscious parts of our brains.

It suggests that context and atmosphere play a more important role in how our designs are experienced than might seem on the surface and that what people say about our designs is less important than what they ultimately do with them.

I thought I would enjoy this book and I did. It isn’t going to teach you where to place elements on the page or how to create hierarchy for your information. It will help you understand how our conscious and unconscious minds work and what really influences people to take action or like something.

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