Choice Blindness

Some choices are easy (“Do you want pepperoni or anchovies on your pizza?”) and some choices are hard (“Are you going to get Amazon Echo or Google Home?”), but most of us like to think that we “know our own mind”—that is, when we finally make a choice, we are clear about our decision. Research by psychologists in Sweden shows that this confidence in our own self-knowledge may not always be justified.

choice blindness

Choice blindness is the failure to recall a choice immediately after we have made that choice.

If you go to an ice cream store, order a chocolate cone, and then accept a strawberry cone without noticing, that is choice blindness. If you go to an electronics store, select the new 55-inch Vizio television, and then fail to notice when they bring out (and expect you to pay for) the far more expensive 55-inch Sony television, that is choice blindness. If you order a burger and fries, and then don’t notice when soup-and-salad is placed in front of you, that is choice blindness.

As you have seen, Johannson, Hall, and their colleagues^[1] found a method for inducing choice blindness in a laboratory setting, but they wanted to do more than simply demonstrate that people sometimes forget their choices. As psychological scientists, their goal is to explore an interesting phenomenon (i.e., choice blindness) to understand why it happens and to see if it tells us anything new about the way our minds work.

The Attraction Preference Experiment

You can learn the basics of the experiment conducted by Petter Johannson, Lars Hall and their colleagues by watching the following video^[2].

Johannson and Hall were curious to see how often people noticed that there was a mismatch between their choice and the picture they were told they had chosen. Here’s how the experiment worked. Imagine that you are sitting across a table from an experimenter, who is dressed in a long-sleeved black shirt. He shows you a pair of pictures of head-and-shoulder shots of two males or two females. On each trial, you indicate which of the two people in the pictures you find more attractive. After you make your choice, the experimenter hands you the card you just pointed at and asks you to explain why you preferred this person.

Except that this didn’t always happen this way. Using a magician’s trick, on some trials, when the experimenter handed you the card, he actually handed you the card you did NOT choose.

Watch this video to see the experimenters explain it.

You can view the transcript for “BBC Choice Blindness” here (opens in new window).

The researchers tested 120 college students (70 female, 50 male). The pictures were all of women. As the video showed, they made their choice and then immediately explained the reasons for their preference. Only 13% of the switches were detected immediately. Approximately 10% more switches were mentioned “retrospectively”, where a participant initially justified choosing the switched face, but later indicated some suspicion that the wrong picture had been presented. Most participants who detected a switch attributed it to a technical error rather than suspecting that it was part of the research procedure.

From Phenomenon to Scientific Exploration

What you saw in the video is what a scientist would call a phenomenon—that is, a behavior that happens under certain conditions. The video showed that, if an experimenter is tricky enough, they can get people to justify choices that they never made.

Any of the choices in the list above could explain—fully or in part—the choice blindness phenomenon, but each idea would need to be tested. That is where the science comes in. The starting point for science is something interesting (a surprising phenomenon). If we are motivated to ask why something happened, then we jump into the real work of science: exploring possible explanations.

The next scientific step systematically (i.e., carefully and with specific purposes) changes elements of the procedures or stimuli to see how these changes affect the results. Remember that our dependent variable is the probability that the change in faces will be detected. So now we try to learn more about change blindness by seeing how changing specific details (independent variables) either increase or decrease people’s likelihood of noticing the switch in faces.

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