Of 2 Minds: How Fast and Slow Thinking Shape Perception and Choice [Excerpt]

In psychologist Daniel Kahneman's recent book, he reveals the dual systems of your brain, their pitfalls and their power















Share on Tumblr

Conflict between an automatic reaction and an intention to control it is common in our lives. We are all familiar with the experience of trying not to stare at the oddly dressed couple at the neighboring table in a restaurant. We also know what it is like to force our attention on a boring book, when we constantly find ourselves returning to the point at which the reading lost its meaning. Where winters are hard, many drivers have memories of their car skidding out of control on the ice and of the struggle to follow well-rehearsed instructions that negate what they would naturally do: “Steer into the skid, and whatever you do, do not touch the brakes!” And every human being has had the experience of not telling someone to go to hell. One of the tasks of System 2 is to overcome the impulses of System 1. In other words, System 2 is in charge of self-control.
 

ILLUSIONS

To appreciate the autonomy of System 1, as well as the distinction between impressions and beliefs, take a good look at figure 3.

This picture is unremarkable: two horizontal lines of different lengths, with fins appended, pointing in different directions. The bottom line is obviously longer than the one above it. That is what we all see, and we naturally believe what we see. If you have already encountered this image, however, you recognize it as the famous Müller-Lyer illusion. As you can easily confirm by measuring them with a ruler, the horizontal lines are in fact identical in length.

Now that you have measured the lines, you—your System 2, the conscious being you call “I”—have a new belief: you know that the lines are equally long. If asked about their length, you will say what you know. But you still see the bottom line as longer. You have chosen to believe the measurement, but you cannot prevent System 1 from doing its thing; you cannot decide to see the lines as equal, although you know they are. To resist the illusion, there is only one thing you can do: you must learn to mistrust your impressions of the length of lines when fins are attached to them. To implement that rule, you must be able to recognize the illusory pattern and recall what you know about it. If you can do this, you will never again be fooled by the Müller-Lyer illusion. But you will still see one line as longer than the other.

Not all illusions are visual. There are illusions of thought, which we call cognitive illusions. As a graduate student, I attended some courses on the art and science of psychotherapy. During one of these lectures, our teacher imparted a morsel of clinical wisdom. This is what he told us: “You will from time to time meet a patient who shares a disturbing tale of multiple mistakes in his previous treatment. He has been seen by several clinicians, and all failed him. The patient can lucidly describe how his therapists misunderstood him, but he has quickly perceived that you are different. You share the same feeling, are convinced that you understand him, and will be able to help.” At this point my teacher raised his voice as he said, “Do not even think of taking on this patient! Throw him out of the office! He is most likely a psychopath and you will not be able to help him.”

Many years later I learned that the teacher had warned us against psychopathic charm,and the leading authority in the study of psychopathy confirmed that the teacher’s advice was sound. The analogy to the Müller-Lyer illusion is close. What we were being taught was not how to feel about that patient. Our teacher took it for granted that the sympathy we would feel for the patient would not be under our control; it would arise from System 1. Furthermore, we were not being taught to be generally suspicious of our feelings about patients. We were told that a strong attraction to a patient with a repeated history of failed treatment is a danger sign—like the fins on the parallel lines. It is an illusion—a cognitive illusion—and I (System 2) was taught how to recognize it and advised not to believe it or act on it.



9 Comments

Add Comment
View
  1. 1. Asteroid Miner 08:43 AM 6/16/12

    There is a problem with the figures. I see only a little blue square.

    Reply | Report Abuse | Link to this
  2. 2. kered 09:30 AM 6/16/12

    Excellent article, but would be MUCH better if we could see the pictures. EDITOR... please reformat so we can read easily... Using system 1 for the pics!!!!!!

    Reply | Report Abuse | Link to this
  3. 3. mike_midwest 02:33 PM 6/17/12

    17x24 = 17x3x8 = 51x8 = (50+1)x8 = 400+8 = 408.

    Reply | Report Abuse | Link to this
  4. 4. HdeJong 04:30 PM 6/17/12

    (16+1)*25-17 = 425-17 = 408

    Reply | Report Abuse | Link to this
  5. 5. kered 07:27 PM 6/17/12

    hard math... try this way
    17*24= 20*24-3*24 = 480-72=408
    I am out of practice, took me ~~30 mins to figure this out... Whatever way, System 2, as System 1 cannot do these!!! Great article

    Reply | Report Abuse | Link to this
  6. 6. hugoal 06:31 AM 6/18/12

    Try this way:
    17*24=10*24+(10-3)*24=240+(240-72)=240+168=408
    or this one that's even easier:
    17*24=(10+10/2+2)*24=10*24+(10*24)/2+2*24=240+240/2+48=240+120+48=408
    Great article.

    Reply | Report Abuse | Link to this
  7. 7. euroflycars 04:15 PM 6/18/12

    Try that way:

    17*2=34 --> 17*20=340
    17*4=68

    340+68=408

    It's opportunistic, but that's why clever calculators will do it almost intuitively with their system 1.

    Reply | Report Abuse | Link to this
  8. 8. GeorgeOckel 05:24 PM 6/20/12

    Article seems interesting but without pictures loses appeal

    Reply | Report Abuse | Link to this
  9. 9. craigc0 03:48 PM 8/7/12

    needs the pictures. This has been noted many times, but no response.

    Reply | Report Abuse | Link to this
Leave this field empty

Add a Comment

You must sign in or register as a ScientificAmerican.com member to submit a comment.
Click one of the buttons below to register using an existing Social Account.

More from Scientific American

Follow Us:

See what we're tweeting about

Scientific American MIND

More »

Free Newsletters


Get the best from Scientific American in your inbox

Solve Innovation Challenges

Powered By: Innocentive

  SA Digital
  SA Digital

Science Jobs of the Week

Email this Article

Of 2 Minds: How Fast and Slow Thinking Shape Perception and Choice [Excerpt]

X
Scientific American Mind

Subscribe Today

Save 66% off the cover price and get a free gift!

Learn More >>

X

Please Log In

Forgot: Password

X

Account Linking

Welcome, . Do you have an existing ScientificAmerican.com account?

Yes, please link my existing account with for quick, secure access.



Forgot Password?

No, I would like to create a new account with my profile information.

Create Account
X

Report Abuse

Are you sure?

X

Institutional Access

It has been identified that the institution you are trying to access this article from has institutional site license access to Scientific American on nature.com. To access this article in its entirety through site license access, click below.

Site license access
X

Error

X

Share this Article

X