Marshmallow Test

Remember the famous Marshmallow Test? If you live in the US, your parents probably tried it on you at some point when you were a kid. It was a very popular experiment allegedly predicting that the children with higher levels of self-control will be more successful in their adult life. It was so influential that all books about raising children would discuss the importance of self-control and willpower and provide tips for developing them in kids.

The experiment was designed by Stanford psychology professor Walter Mischel in 1970 and was quite simple in its set up: children between 4 and 5 years old were presented with a marshmallow on a plate, which they could eat immediately. Or, if they waited for the experimenter for several minutes alone in the room, they would get one more marshmallow after the experimenter returns. The kids were never told how long they would have to wait, although for a 4-5-year old the concept of time is pretty abstract anyway. I am not sure how the researchers determined the length of time, but some kids had to wait much longer than others.

Here's a later replication of the experiment for a TV show. Notice how it presents only two results at the end: one child eating the marshmallow immediately, and one - after the experimenter returned and gave him the second one.

In the 1970 study, the subjects were followed for 40 years to observe possible correlations. During adolescence, Mischel discovered that the children who delayed the reward showed better grades and their parents observed a greater capacity to plan, deal with stress, respond reasonably, exhibit self-control in frustrating situations and concentrate without being distracted.

The girl who waited for the second marshmallow the longest in the entire group was Susan Wojcicki, who became a CEO of YouTube later in life. Her mother Esther even wrote a book titled "How to Raise Successful Children," where one of the central ideas was - you probably guessed it - developing the child's self-control, discipline and the willpower.

As a final result, the researchers made a conclusion that there was a correlation between self-control and personal and professional “success.” Consequently, the longer a child was able to delay the reward, the better their academic results, the higher salaries, and healthier and fuller lives. Meanwhile, those who had not been able to control themselves were more likely to have problems with obesity and drug use.

This study is considered to be so central to child development and psychology that it has influenced pedagogy and child raising for many years. Until in the late 1990s, someone came in, looked at the original study subjects and said, "This small group is not diverse at all, it includes white kids only and more boys than girls. Let's see if we can replicate the experiment with a more diverse group of children and control for some other factors."

The control variable they were interested in and split the new groups of participants on was the mother's education: Kids were assigned into two groups, those whose mothers had college degree or higher and those who did not. The logic was simple: Educated mothers will put more time and effort in developing their children's self-control as they will be more likely to know of its importance for success in life. The researchers also controlled for other variables such as income, family background, and cognitive abilities of the children.

Even the initial results in this bigger experiment showed that self-control may not be the key but rather a secondary variable. What predicted who ate the marshmallow right away instead of waiting for the second one was the family income. The explanation is on the surface: Children from wealthier families whose parents would eventually buy them the toys and candies they wanted were more patient than children from poorer families who could not rely on the promise of marshmallow in the future and pursued instant gratification by eating it right away.

The conclusion from this more refined experiment is that while self-control may be important indeed, it is easier to develop in children who already have a systemic advantage of being brought up in wealthier families. For any society to develop successful adults with high levels of self-control and discipline, they should not be living in scarcity conditions as children. The countries that illustrate this very well are Finland, Denmark, Norway, and Sweden.

Another good reason to tax the uber-rich.