Many decisions involve intertemporal choice: a choice between options whose consequences occur at different points in time. For example, choosing whether or not to eat cake when you also want to lose weight this month. Remarkably, we often choose small immediate rewards (e.g. eat cake) over large future benefits (e.g. lose weight), despite different intentions. How can we become better at resisting temptations and align our behavior with our long-term intentions? ‘Nudging’, a concept from behavioral economics, appears a promising strategy: by designing choice contexts that exploit our cognitive biases, it gently guides us into making choices that are better for ourselves and society. One way to nudge intertemporal choice is by ‘framing’ the timing of the choice outcome in a certain way: e.g. we make more patient choices when future outcomes are described in terms a speedup than in terms of a deferral (Figure 1A) or when they are described in terms of calendar dates than in terms of corresponding delays (Figure 1B). However, the use of time framing in practice is hampered because we do not know how time framing works. If we do not address this problem, we will not understand our seemingly irrational choices and we will be limited in developing novel framing interventions that change behavior. To address this problem, this project aims to determine the mechanisms of time framing in intertemporal choice, using a behavioral experiment and new computational models. Our working hypothesis is that time framing changes how we perceive time.