40 Years of Stanford Research Found That Being Able to Delay Gratification Depends on Your Past Experiences

Have you ever felt cold in an office? Or noticed how many women complain about the office being chilly?

That’s because the standard room temperature was devised using a 40-year-old man weighing 154 pounds to calculate the default metabolic rate.

In fact, because of biological differences (some in a study here), on average, women prefer the indoor room temperature to be 77. Men? 71. Of course people are unique, but the gender differences in these averages is robust. Robust enough so that you’ve probably noticed it. (Feeling uncomfortably cold in an office can actually take a toll on your productivity.)

Selection bias refers to the way that a non-random group of research subjects can skew or alter the results. If I was at a basketball game and “randomly” wandered down to the court and measured the height of five players, I shouldn’t use that data to make a claim about the average height of men in the arena. This bias creeps up in psychology studies all the time—even when we don’t realize it.

Surely you’ve heard of The Marshmallow Test. If not: a researcher at Stanford named Walter Mischel began testing kids’ ability to delay gratification. In his seminal study, he placed children in front of a piece of candy. Before he left them alone with it, he told them that if they could hold off eating it until one of the researchers returned—roughly 15 minutes—they’d be ultimately be rewarded with two marshmallows.

The children who were able to wait for the second marshmallow not only scored higher on their SATs, but reached higher levels of career success than their grabby peers. They were less likely to abuse substances or be obese; even their relationships were better. In a huge follow-up study 40 years after the original one, researchers found differences in how the brains of “delayers” and the “nondelayers” responded to rewards.

Well, duh. Isn’t it obvious that the ability to delay gratification is important? James Clear made that the theme in “40 Years of Stanford Research Found That People With This One Quality Are More Likely to Succeed.” Angela Duckworth’s famous TED talk on grit also hammered this idea. Keeping your eyes on the prize over the long term is crucial for success. Grit, the ability to delay gratification, perseverance, self-regulation, self-control—whatever you want to call it—leads to good things. But not always.

One main problem with the original study was the selection bias in Mischel’s studies.

“The original results were based on studies that included fewer than 90 children—all enrolled in a preschool on Stanford’s campus.” [The Atlantic]

In other words, the kids who participated in the study did not represent a random sample of kids, meaning that we can’t make a claim about how that result applies to everyone. They were upper middle class and white. Their parents had some affiliation with Stanford—even if just living in that area. They were the perfect example of what Joseph Henreich called WEIRD in a famous paper: Western, Educated, Individual, Rich, and Democratic.

“In restaging the experiment, Watts and his colleagues thus adjusted the experimental design in important ways: The researchers used a sample that was much larger—more than 900 children—and also more representative of the general population in terms of race, ethnicity, and parents’ education.” [Atlantic]

According to Psychological Science: “The results showed that, although children who were able to wait and resist temptation tended to have stronger math and reading skills in adolescence, the association was small and disappeared after the researchers controlled for characteristics of the child’s family and early environment.”

Behavior is the product of both the person and the situation. This is a form of attribution bias: thinking that not waiting for the marshmallow points to ingrained flaws in someone’s character, when in fact not waiting may just be a rational response to an otherwise shitty situation.

What if you, as a kid, had seen people wait for the marshmallow and come up empty-handed? What if an adult who promised you a marshmallow never followed through? What if you had seen that scenario play out several times?

External circumstances and environments exert a compelling impact on our lives, teaching us when and where our efforts are even worthwhile. It’s logical—it’s how we learn. People repeat behaviors that have been rewarded in the past. If you learn that hard work and patience will pay off and make that effort worthwhile, you’re more likely to try.

If you have a hard time waiting for the second marshmallow, consider your past experiences. For example, suffering from a macroeconomic shock (seeing scads of second marshmallows being yanked away) can alter your entire life, if it happens at a critical moment in your life.

In “Growing Up in a Recession,” Italian economists found that this can happen to an entire generation:

We find that individuals who experienced a recession when young believe that success in life depends more on luck than effort, support more government redistribution, and tend to vote for left-wing parties. The effect of recessions on beliefs is long-lasting.

Remember: waiting, being patient, and being able to delay gratification are adaptive behaviors. But they’re much easier to develop and practice if you’ve always had people follow through.

If you can’t wait for the Marshmallow, ask yourself: do you trust that you’ll get a second one? Or do you believe that it’s chance?