Testing the Ability to Delay Gratification: Does One Marshmallow Really Tell it All?

Emma Stewart

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If taking one test could provide you with meaningful information about your outcomes in life — your educational attainment, body mass index, social competence, verbal fluency, and ability to deal with stress — would you call this a good projective test? According to Walter Mischel’s “Marshmallow Experiment,” a preschooler’s ability to delay eating a marshmallow for 15 minutes shows consistent correlations with all of these outcomes (Mischel, W., Shoda, Y., Rodriguzez, M.L., 1989; Shoda, Y., Mischel, W., Peake, P.K., 1990; Ayduk, O.N., Mendoa-Denton, R., Mischel, W., Downey, G., Peake, P.K., Rodriguez, M.L., 2000; Schlam, T.R., Wilson, N.L., Shoda, Y., Mischel, Walter; Ayduk, Ozlem, 2013). This study is about being able to defer gratification, meaning putting off receiving something you want (like a marshmallow) in order to receive something better at a later time. However, I think this experiment is often perceived as a psychological test of a child’s ability to delay gratification, and in my opinion there are problems with this interpretation.

In this study, a child is brought into the lab and given a marshmallow. They are told that if they can wait until the experimenter returns (15 minutes) without eating the marshmallow, they can have a second one as well. The idea behind this task is that a child will always prefer to receive two marshmallows. Despite the clear relationships between this simple test and later outcomes, I think there are several problems with the way it is set up, if it is to function as a psychological test.

First of all, in order to test deferred gratification, it is necessary to ensure that both the immediate and delayed outcomes are desirable, and that the delayed outcome is the more desirable one. Evidently, people have different food preferences, and some children will like the food presented to them a lot more than others will. For a child who likes marshmallows a lot, this will certainly be a difficult task for them to complete, but it will most likely be worth it in the end. However, for a child who is completely neutral to whether or not they receive a marshmallow, there will be no incentive to await the second one. Additionally, there may be very little incentive even for a child who does like marshmallows. According to the law of diminishing returns, the second marshmallow is likely to have less value than the first, which means that for a child who only likes marshmallows a bit, the value of the second one may be close to zero.

Secondly, there may be other factors that affect whether or not a child is motivated to wait for the marshmallow. For instance, a child who values the approval of others very highly is more likely to wait for the entire length of time, for sake of pleasing the experimenter or their parents. On the other hand, those who do not value this as highly may be receiving less reward for the same amount of work. Additionally, some children may find waiting on their own in a room a very unpleasant task, no matter what the reason. For them, it may be more intelligent to just eat the marshmallow, if they value leaving the room more than they value a second marshmallow.

I think it is important to consider that there may be a difference between a child who really wants to wait for the entire time, but is unable to due to the temptation of the immediate reward, and a child who has simply decided that waiting is not worth the reward they will receive. Whether it be because they do not value the second marshmallow very highly, or because there are other factors playing a role, children may make decisions that are actually better than simply waiting, and react to this test in ways that do not reflect their actual ability to defer gratification. I think there are a lot of children for whom this is not measuring the desired construct at all, and using this as a test may be giving parents or the children themselves false ideas about their abilities.

Despite these criticisms, I think this task could function as a psychological test, if certain changes were made. For instance, it would need to include a rating system to determine how much a child values the amount of the food being used. The rating would be done immediately before they performed the task, to control for the child being hungry, feeling sick (and not in the mood to eat) or craving having that food immediately. They would then have to rate how much they would like to receive twice as much of it. On the same scale, they would need to express how much they valued doing whatever they were previously doing, as opposed to doing this task for the set amount of time. It would have to be made clear that whether or not the child ate the food immediately or waited was completely their choice, and that they would not receive more love or approval either way. In order for this to be an accurate measurement, the child would have to value having twice as much food more than having the original amount of food and stopping the task immediately. If these conditions are not met, then there are other factors affecting the child’s behaviour, other than their ability to delay gratification. If these conditions are met however, I think this task would serve as a fairly good psychological test.

References

Ayduk, O.N., Mendoa-Denton, R., Mischel, W., Downey, G., Peake, P.K., Rodriguez, M.L. (2000). “Regulating the interpersonal self: Strategic self-regulation for coping with rejection sensitivity.” Journal of Personality and Social Psychology 79 (5), 776–792. doi:10.1037/0022–3514.79.5.776.

Mischel, W., Shoda, Y., Rodriguzez, M.L. (1989). “Delay of gratification in children.” Science 244, 933–938. doi:10.1126/science.2658056.

Schlam, T.R., Wilson, N.L., Shoda, Y., Mischel, W., Ayduk, O. (2013). “Preschoolers’ delay of gratification predicts their body mass 30 years later”. The Journal of Pediatrics 162, 90–93. doi:10.1016/j.jpeds.2012.06.049.

Shoda, Y., Mischel, W., Peake, P.K. (1990). “Predicting Adolescent Cognitive and Self-Regulatory Competencies from Preschool Delay of Gratification: Identifying Diagnostic Conditions.” Developmental Psychology 26 (6), 978–986. doi:10.1037/0012–1649.26.6.978.