Rational snacking: young children's decision-making on the marshmallow task is moderated by beliefs about environmental reliability

Abstract

Children are notoriously bad at delaying gratification to achieve later, greater rewards (e.g., Piaget, 1970)-and some are worse at waiting than others. Individual differences in the ability-to-wait have been attributed to self-control, in part because of evidence that long-delayers are more successful in later life (e.g., Shoda, Mischel, & Peake, 1990). Here we provide evidence that, in addition to self-control, children's wait-times are modulated by an implicit, rational decision-making process that considers environmental reliability. We tested children (M=4;6, N=28) using a classic paradigm-the marshmallow task (Mischel, 1974)-in an environment demonstrated to be either unreliable or reliable. Children in the reliable condition waited significantly longer than those in the unreliable condition (p<0.0005), suggesting that children's wait-times reflected reasoned beliefs about whether waiting would ultimately pay off. Thus, wait-times on sustained delay-of-gratification tasks (e.g., the marshmallow task) may not only reflect differences in self-control abilities, but also beliefs about the stability of the world.

Copyright © 2012 Elsevier B.V. All rights reserved.

Figures

Fig. 1

Mean wait-times of children in each condition. Error bars show 95% confidence intervals. Children in the unreliable condition waited without eating the marshmallow for a mean duration of 3 min and 2 s (M = 181.57 s). In contrast, those in the reliable condition waited 12 min and 2 s (M = 722.43 s). A Wilcoxon signed-rank test found this difference to be highly significant (W = 22.5, p < 0.0005). Here, 15 min was used as the wait-time for children who did not eat the marshmallow until the researcher returned, though these children may have actually waited longer if the experimental design had permitted.

Fig. 2

Proportion of children who waited the full 15 min without eating the marshmallow by condition. Error bars show 95% confidence intervals. In the unreliable condition, only 1 out of the 14 children (7.1%) waited the full 15 min; in the reliable condition, however, 9 out of the 14 children (64.3%) waited. We tested the difference using a two-sample test for equality of proportions with continuity correction at α2-tail = 0.05. The test found it to be highly significant (X2 = 7.6222, df = 1, p < 0.006).