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We asked half of them to predict for us how much their values would change in the next 10 years, and the others to tell us how much their values had changed in the last 10 years. And this enabled us to do a really interesting kind of analysis, because it allowed us to top university compare the predictions of people, say, 18 years old, to the reports of people who were 28, and to do that kind of analysis throughout the lifespan.
Here's what we found. First of all, you are right, change does slow down as we age, but second, you're wrong, because it doesn't slow nearly as much as we think. At every age, from 18 to 68 in our data set, people vastly underestimated how much change they would experience over the next 10 years. We call this the "end of history" illusion. To give you an idea of the magnitude Zero Moment Of Truth of this effect, you can connect these two lines, and what you see here is that 18-year-olds anticipate changing only as much as 50-year-olds actually do.
Now it's not just values. It's all sorts of other things. For example, personality. Many of you know that psychologists now claim that there are five fundamental dimensions of personality: neuroticism, openness to experience, agreeableness, extraversion, and conscientiousness. Again, we asked people how much they expected to change over the next 10 years, and also how much they had changed over the last 10 years, and what we found, well, you're going to get used to seeing this diagram over and over, because once again the rate of change does slow as we age, but at every age, people underestimate how much their personalities will change in the next decade.
And it isn't just ephemeral things like values and personality. You can ask people about their likes and dislikes, their basic preferences. For example, name your best friend, your favorite kind of vacation, what's your favorite hobby, what's your favorite kind of music. People can name these things. We ask half of them to tell us, "Do you think that that will change over the next 10 years?" and half of them to tell us, "Did that change over the last 10 years?" And what we find, well, you've seen it twice now, and here it is again: people predict that the friend they have now is the friend they'll have in 10 years, the vacation they most enjoy now is the one they'll enjoy in 10 years, and yet, people who are 10 years older all say, "Eh, you know, that's really changed ."
Is this just a form of mis-prediction that doesn't have consequences? No, it matters quite a bit, and I'll give you an example of why. It bedevils our decision-making in important ways. Bring to mind right now for yourself your favorite musician today and your favorite musician 10 years ago. I put mine up on the screen to help you along. Now we asked people to predict for us, to tell us how much money they would pay right now to see their current favorite musician perform in concert 10 years from now, and on average, people said they would pay 129 dollars for that ticket. And yet, when we asked them how much they would pay to see the person who was their favorite 10 years ago perform today, they say only 80 dollars. Now, in a perfectly rational world, these should be the same number, but we overpay for the opportunity to indulge our current preferences because we overestimate their stability.