The psychology behind irrational decisions - Sara Garofalo

2,287,856 views ・ 2016-05-12

TED-Ed


Please double-click on the English subtitles below to play the video.

00:06
Let's say you're on a game show.
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You've already earned $1000 in the first round
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when you land on the bonus space.
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Now, you have a choice.
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You can either take a $500 bonus guaranteed
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or you can flip a coin.
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If it's heads, you win $1000 bonus.
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If it's tails, you get no bonus at all.
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In the second round, you've earned $2000 when you land on the penalty space.
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Now you have another choice.
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You can either take a $500 loss,
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or try your luck at the coin flip.
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If it's heads, you lose nothing,
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but if it's tails, you lose $1000 instead.
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If you're like most people,
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you probably chose to take the guaranteed bonus in the first round
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and flip the coin in the second round.
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But if you think about it, this makes no sense.
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The odds and outcomes in both rounds are exactly the same.
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So why does the second round seem much scarier?
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The answer lies in a phenomenon known as loss aversion.
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Under rational economic theory,
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our decisions should follow a simple mathematical equation
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that weighs the level of risk against the amount at stake.
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But studies have found that for many people,
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the negative psychological impact we feel from losing something
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is about twice as strong as the positive impact of gaining the same thing.
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Loss aversion is one cognitive bias that arises from heuristics,
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problem-solving approaches based on previous experience and intuition
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rather than careful analysis.
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And these mental shortcuts can lead to irrational decisions,
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not like falling in love
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or bungee jumping off a cliff,
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but logical fallacies that can easily be proven wrong.
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Situations involving probability are notoriously bad for applying heuristics.
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For instance, say you were to roll a die with four green faces and two red faces
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twenty times.
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You can choose one of the following sequences of rolls,
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and if it shows up, you'll win $25.
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Which would you pick?
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In one study, 65% of the participants who were all college students
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chose sequence B
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even though A is shorter and contained within B,
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in other words, more likely.
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This is what's called a conjunction fallacy.
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Here, we expect to see more green rolls,
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so our brains can trick us into picking the less likely option.
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Heuristics are also terrible at dealing with numbers in general.
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In one example, students were split into two groups.
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The first group was asked whether Mahatma Gandhi died before or after age 9,
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while the second was asked whether he died before or after age 140.
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Both numbers were obviously way off,
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but when the students were then asked to guess the actual age at which he died,
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the first group's answers averaged to 50
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while the second group's averaged to 67.
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Even though the clearly wrong information in the initial questions
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should have been irrelevant,
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it still affected the students' estimates.
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This is an example of the anchoring effect,
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and it's often used in marketing and negotiations
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to raise the prices that people are willing to pay.
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So, if heuristics lead to all these wrong decisions,
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why do we even have them?
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Well, because they can be quite effective.
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For most of human history,
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survival depended on making quick decisions with limited information.
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When there's no time to logically analyze all the possibilities,
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heuristics can sometimes save our lives.
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But today's environment requires far more complex decision-making,
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and these decisions are more biased by unconscious factors than we think,
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affecting everything from health and education
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to finance and criminal justice.
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We can't just shut off our brain's heuristics,
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but we can learn to be aware of them.
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When you come to a situation involving numbers,
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probability,
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or multiple details,
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pause for a second
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and consider that the intuitive answer might not be the right one after all.
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