Supplementary methods, figures, analyses, results, and discussion from Intertemporal choice reflects value comparison rather than self-control: insights from confidence judgements

Intertemporal decision-making has long been assumed to measure self-control, with prominent theories treating choices of smaller, sooner rewards as failed attempts to override immediate temptation. If this view is correct, people should be more confident in their intertemporal decisions when they ‘successfully’ delay gratification than when they do not. In two pre-registered experiments with built-in replication, adult participants (n = 117) made monetary intertemporal choices and rated their confidence in having made the right decisions. Contrary to assumptions of the self-control account, confidence was not higher when participants chose delayed rewards. Rather, participants were more confident in their decisions when possible rewards were further apart in time-discounted subjective value, closer to the present, and larger in magnitude. Demonstrating metacognitive insight, participants were more confident in decisions that better aligned with their separate valuation of possible rewards. Decisions made with less confidence were more prone to changes-of-mind and more susceptible to a patience-enhancing manipulation. Together, our results establish that confidence in intertemporal choice tracks uncertainty in estimating and comparing the value of possible rewards—just as it does in decisions unrelated to self-control. Our findings challenge self-control views and instead cast intertemporal choice as a form of value-based decision-making about future possibilities.This article is part of the theme issue ‘Thinking about possibilities: mechanisms, ontogeny, functions and phylogeny’.