The marshmallow test

The marshmallow test experiment implies that a preschooler is offered a candy (it may be a marshmallow, a cookie, or a similar one that is tempting), but is told that if he or she wants a second treat he must wait for the experimenter to return without eating the first. More specifically, this technique consists of a boy or girl being presented with a treat and told that it is for them to keep, but that if they wait without eating it for the evaluator to return, then they will be given a second reward. After this instruction the participant is asked if she or he wants to wait, for which most children around the world to whom this experiment has been applied, decide to do so (^{Mischel, 2014}).

The marshmallow test, apparently a simple experiment to assess personal self-control, generally applied towards the end of early childhood, has been shown to have a statistically significant predictive value on positive results at the educational level (more years of study), work (better placement), economic (better income), family (greater stability) and social (more harmonious and less conflictive relationships) in adult life (^{Mischel, 2014}; ^{Shoda, Mischel, & Peake, 1990}). More recent replicas of the marshmallow test have found that while these predictions show statistical significance, their effect is moderate and highly sensitive to the inclusion of covariates, such as interpersonal, cultural, and socioeconomic context (^{Lamm et al., 2018}; ^{Michaelson & Munakata, 2016}; ^{Watts, Duncan & Quan,2018}).

When analyzing people decades after they had performed the experiment, the evidence suggests that those who had managed to wait as long as they had (approximately 15 minutes - which can vary from one methodological design to another) when they were about five years old, tended to present better results in their adult lives in various areas, which seems to point to the predictive importance of the capacity for self-control in development, and more specifically, the ability to postpone rewards to obtain more beneficial results later. This may be related to the ability to plan behavior in the long term, postponing immediate rewards, to obtain better outcomes later (^{Mischel, 2014}).

However, recent replications of this work have come to question its predictive value and its validity as a measurement technique, given the relatively low correlations obtained between the performance in the marshmallow task and the cognitive and social results achieved subsequently, as well as the high correlations between the favorable performance of children in this task and their social environment (high socioeconomic status, living with both parents, absence of severe social conflict; ^{Watts et al., 2018}).

Social context and self-control in decision-making

Recent research (^{Chaverri, Conejo, León, & Arrieta, 2020}; ^{Kidd, Palmeri, & Aslin, 2013}) has managed to determine that the social context in which people operate has a profound influence on how they make decisions, not only in general terms, but in specific instances and dynamics of this interaction. In this sense, it has been demonstrated that experiencing situations of scarcity, environmental instability, and the perception of living in conditions of low socioeconomic status, have direct implications on cognitive and regulatory skills in contexts of attention to immediate needs, on the ability to solve problems that involve some degree of reasoning, as well as on stress management, academic performance and eating habits (^{Shah, Mullainathan, & Shafir, 2012}). Generally speaking, it can be said that a deprived social environment can lead people to make more impulsive decisions and be less able to consider a long-term vision.

The interaction between rationality and emotion

Traditionally, the decision-making literature equated rationality with maximizing the value of a potential gain (^{Smith & Kosslyn, 2011}; ^{Sternberg, 2011}). This expected utility model was based on three basic assumptions about the person making the decision: 1) That they are fully informed about all possible choice options, 2) They are very sensitive to subtle distinctions between existing options, and 3) They are totally rational about the choice between options (^{Slovic, 1990}).

Consistently, obtaining better results in the marshmallow test was explained from the rational theory of decision making (^{Mischel & Staub, 1965}), based on the fact that what this experiment does is to compare a choice between a lower immediate gratification and a higher subsequent gratification, which is related to the idea of people as utility magnifying agents, typical of the rational theory of decision making, so that a higher waiting time could be explained within this theory in terms of a higher rationality.

But is it only rationality that explains the differences? According to rational decision-making theory, human beings are agents who make decisions in a utilitarian way, seeking to increase profits and reduce losses (^{Smith et al., 2012}). However, the most recent research in behavioral economics, psychology and cognitive neuroscience has been showing that people are, much more often than is usually assumed, not very rational decision makers (^{Ariely, 2010}; ^{Kahneman, 2011}), if rationality is defined in the terms of the assumptions made by the expected utility model.

One line of research that puts this question into perspective is the "ultimatum game" (^{Jensen, Call, & Tomasello, 2007}). In this game, two people, sitting opposite each other, must decide how to distribute resources given to them. For example, ten money bills of the same denomination are given to one of the players (the offeror), who must decide how to distribute them with his counterpart, being that, if the receiver rejects the deal, both players are left with nothing. On the other hand, if the receiver accepts the deal, then both players stick with what the offering player proposed (^{Güth, Schmittberger, & Schwarze,1982}).

Following the model of expected utility in decision-making, players should reject any offer equal to zero (because it implies not obtaining any profit) and accept any offer equal to or greater than one (because it implies improving the original situation that is zero). However, people do not act like this, since, in a distribution with a total of 10 units, they tend to reject those offers in which they are assigned two or fewer units and accept those that make them earn three units or more (^{Jensen et al., 2007}). In addition, if the offer is given by a person, the recipient tends to a greater rejection of low offers (8:2 or 9:1) than if the offeror is a computer, in which case there is a greater acceptance of low offers. This suggests the influence of a judgment on the moral capacity of the counterparty (^{Fehr, 2009}).

This decision-making behavior does not fit with what is expected by the rational theory, in which all offers that imply a profit should be accepted. Why does this happen? One possibility that has supporting evidence is that when people find themselves in contexts of interdependence with each other, rather than classifying offers in a merely rational and utilitarian way, a more emotional and presumably moral weighting seems to occur (^{Sanfey, Rilling, Aronson, Nystrom, & Cohen, 2003}). This is supported by the aforementioned finding that when the to the offeror isa computer, there tends to be less rejection of offers than when playing with another person, which suggests a moral judgment about the intentions of the counter party. On the other hand, when low offers are received (which would be considered unfair in an interpersonal context) there is a greater activation of brain areas associated with emotional processing (for example the right anterior insula) compared to the brain processing of information in egalitarian offers. This suggests that there is an increased role of emotion when an unequal offer is received. In addition, people with a greater activation of the right anterior insula against low offers, reject such offers in greater proportion (^{Sanfey et al., 2003}), suggesting an interaction between this emotional processing and rejection.

In the study carried out by ^{Sanfey et al. (2003}), participants were brain scanned with functional magnetic resonance imaging during playing the ultimatum game, responding both to proposals categorized as fair (tending to 50/50 parity) and unfair (moving closer to total disparity 0/100). Unfair offers triggered activity in brain areas related to both emotion (anterior insula) and cognition (dorsolateral prefrontal cortex). This evidence suggests an important role for emotions in this decision-making.

Contrary to what the expected utility model predicts, decision-making in interpersonal contexts, far from being an exclusively utilitarian process, consists of an emotionally and morally mediated process, an idea that has been strengthened in recent years due in part to research that tries to understand the mind and human behavior within its environment, analyzing specific interactions, as well as the role of emotions, which are not there to interrupt, distract or mislead, but are important for cognitive functions and decision-making in a contextualized way. It is important to note that there is still much to understand about these processes, and future research should explore the specific mechanisms by which emotion and cognition are intertwined in decision making process (^{Damasio, 2018}; ^{Todd & Gigerenzer, 2012}). Given the above, it can be argued that recent research suggests that emotions, morality, and social context are important factors to consider in understanding the way people make decisions and exercise their self-control skills, without denying this the importance of cognition and reasoning, but rather recognizing the need to achieve a deeper understanding of how these elements interact with each other.

As ^{Todd and Gigerenzer (2012}) argued, the future of decision-making research should understand these interactions between the mind and its environment, expanding the focus of those social scientists more attached to the traditional theory of rational choice. From our point of view, our knowledge about the relation between decisions and emotions is rather limited, and the field needs to better understand how we develop our cognitive and emotional repertoire to make decisions, so it is necessary to strengthen research in this direction.

Conclusion

As suggested by the research reviewed here, self-control cannot be considered an independent capacity from the environment, since it is influenced by the circumstances that shape our ability to make decisions, being interpersonal trust a relevant aspect of this person-environment interaction.

When a child decides not to wait for the second marshmallow after being exposed to a deception from his or her counterpart (as occurs in the experiment reviewed here when a promise is broken), instead of judging his or her act as irrational, we should rather consider the emotional context that produces the induced distrust, to understand the way in which the child's action adapts to the structure of his or her environment, according to what is proposed by the theory of situated cognition and the theory of ecological rationality. When a person is not emotionally comfortable in a given situation, it may be appropriate to try to see what that negative emotion means in that context, rather than simply try to inhibit it by considering it "an obstacle" to reasoning.

That a person in a more insecure, unstable, and deprived context acts more impulsively and shows more difficulty in delaying a reward, could be considered an adaptive response to such characteristics of his or her context, since it could be said that experience has taught him that the promises of others and his environment cannot be trusted a priori, since he lives in an environment where they are usually broken easily, and expectations are often unfulfilled. Is this person less rational? If the interaction between the person and the environment is taken into consideration, as proposed by the theory of ecological rationality, and situated cognition, it can be seen that not waiting for the second treat can be considered an adaptive behavior in some circumstances.

When the context of a person is taken into account, it can be understood that someone who lives in a safer, more stable, and satisfactory situation, could more easily inhibit the impulses of immediate satisfaction and wait, since they can have more hope for promises to be fulfilled, because he is more accustomed to it being so. Offering community and educational environments that strengthen the sense of stability and basic confidence of children is essential to promote their capacity for self-control, decision-making and adaptive behaviors.