Mahzarin R. Banaji - Blindspot: Hidden Biases of Good People

Like all vertebrates, you have a blind spot in each eye. This is a small region where the optic nerve attaches to the retina. Because there are no light-sensitive cells in this region, light reaching your blind spot (scotoma) has no path to visual areas of your brain.

Nevertheless, you can see your own blind spot by looking at the plus sign in the middle of the rectangle below with just one eye open. (You may need to take your glasses off.) Starting with the page about a foot in front of your nose, bring it closer while focusing on the plus sign. One of the black discs (the one on the same side as your open eye) will disappear at some point when the page is about six inches away, and will reappear as you bring the page closer still. The moment of disappearance tells you when light from that disc is falling on your open eyes blind spot. Heres a bonus: If you shift your open eye to look at the still-visible disc on the other side, the plus sign will disappear!

You may have also noticed a strange occurrence at the spot where the disc lies. When the disc disappeared, it left no blank spot in the grid background. Your brain did something interestingit filled in the scotoma with something that made sense, a continuation of the same grid that you could see everywhere else in the framing rectangle.

A much more dramatic form of blindness occurs in the pathological condition called blindsight, which involves damage to the brains visual cortex. Patients with this damage show the striking behavior of accurately reaching for and grasping an object placed in front of them, while having no conscious visual experience of the object. If you placed a hammer before the patient and asked, Do you see something before you? the patient would answer, No, I dont, but when asked to just reach for and grasp the hammer, she would do so as accurately as if she could see. This happens because the condition of blindsight leaves intact subcortical retina-to-brain pathways that suffice to guide behavior, even in the absence of the conscious experience of seeing the hammer.

We understand both the retinal blind spot and clinical blindsight as metaphors that help in understanding thoughts and feelings of which we are not aware, but which nevertheless guide our behavior. The hidden-bias blindspot of this books title has some features of both the retinal blind spot and blindsight. Like the retinal blind spot you experienced, we normally have no awareness of hidden biases. And like the dramatic phenomenon of clinical blindsight, hidden biases are capable of guiding our behavior without our being at all aware of this guidance.

Hidden biases of the sort we find interesting can cause us to judge and act toward others in favorable or unfavorable ways that come from unrecognized feelings and beliefs about the groups to which people belong. In talking with many people about hidden biases, we have discovered that most find it simply unbelievable that their behavior might be guided in this fashion, without their awareness. Our main aim in this book is to make clear why scientists now regard this blindspot as fully believable. Convincing readers of this is no simple challenge. How can we show the existence of something in our own minds that is hidden from our own awareness?

Just as the rectangle with the two black discs allows us to see the otherwise hidden retinal blind spot, a device called the Implicit Association Test has enabled us to discover the contents of hidden-bias blindspots. Even better than the demonstration of the retinal blind spot, which allows us to know that we have a blind spot but not much more, the Implicit Association Test (IAT for short) lets us look into the hidden-bias blindspot and discover what it contains.

It is not often that scientists can learn something about their own minds while doing their research, but we have been the beneficiaries of such experiences. In addition to being a scientifically valuable device that we and many others have used in research for the past seventeen years, the IAT has also confronted us personally with some unwelcome, insight-provoking experiencesbringing us face-to-face with the contents of our own blindspots. In this book we give readers the opportunity to likewise experience the contents of their own blindspots.

Here is a brief overview of whats to be found in this book.

We begin with Mindbugs (Chapter 1), which sets the stage for understanding hidden-bias blindspots. In it, we show how humans routinely use available information around them without being aware either that they are doing this or of how unthinkingly they are doing it. With prove-it-to-yourself demonstrations (a favorite method of ours) that engage your eyes and your mind, we demonstrate biases to be unwanted consequences of mental adaptations that may have been evolutionarily helpful in our species past.

In Shades of Truth (Chapter 2), we lay a basis for understanding why we want to move well beyond long-established research methods that rely on verbal answers to researchers questions. We lay out several varieties of untruths (lies) that occur in the process of answering questions. These include routine self-deceptions that keep us from recognizing truths about ourselves. Most of the untruths we describe in Chapter 2 are not deliberate attempts to deceive. Rather, they are part of an armory of mental strategies that humans routinely deploy with no active thought about what they are doing.

A crucial moment in the book arrives when we dive Into the Blindspot (Chapter 3), where you will have the chance to discover hidden biases of your own. This is where we present and explain the IATthe invention that made this book possible. At the website implicit.harvard.edu anyone can sample multiple IATs with complete anonymity, adding to the 14 million tests that have already been sampled.