Research
Individual differences in temporal discounting
Would you rather have $20 now or $40 in one year?
People often have to make intertemporal choices like these, in which they choose between smaller, sooner rewards and larger, later rewards. People vary in how much they “discount” the value of rewards that are delayed in time (a phenomenon known as temporal discounting), and these temporal discounting rates are associated with real-world outcomes. Where do these individual differences come from? Historically, they have been attributed to individual differences in inhibitory control. However, more recent evidence suggests that the extent to which people make future-oriented choices depends on episodic and semantic memory. The mechanism by which memory shapes intertemporal preferences is still unclear, though. One idea that we are testing in the lab is that, at the time of choice, people retrieve conceptual information about how long time intervals (e.g., one year) usually last. These concepts may differ from one person to the next, since our episodic memory for time depends on factors such as the predictability of the environment. We are investigating this question using memory and choice tasks, as well as pupillometry and functional neuroimaging. We also try to understand the impact of episodic memory on choice more broadly, by studying how age-related changes in memory affect decision making in older adults.
Toward a taxonomy of impulsivity
What does it mean to be impulsive?
Psychologists have long acknowledged that impulsivity is a multidimensional construct, and questionnaire measures of impulsivity have had some success in distinguishing among different kinds of impulsive behavior, ranging from sensation seeking to urgency to a lack of premeditation. And yet, the majority of studies on impulsive choice have used the temporal discounting task, which only really captures people’s attitudes toward future rewards when their timing is known. Even people who do not seem impulsive when choosing between immediate and future rewards may act differently when there is uncertainty about the timing of a future reward, and/or when there is an opportunity cost inherent in pursuing a future reward. Can we use our understanding of decision systems in the brain to distinguish among distinct kinds of impulsivity? How do these kinds of impulsivity relate to each other? Do they differ in the kinds of outcomes that they predict in the real world?
Emotion and decision making
What is the role of emotion in valuation?
Historically, it’s been assumed that emotion is the enemy of reason, and that we would be better off using logic to decide what to do. On the other hand, emotions motivate us, and without them, we might not be able to act at all. Research shows that the effects of emotion on choice are nuanced and variable. This makes sense, since emotion contains different components (e.g., arousal, subjective feeling) and plays out over different time scales (e.g., stress, mood, a gut reaction), and decisions are complex as well (do they involve uncertainty, ambiguity, other people?). Some of the lab’s research focuses on delineating how emotion impacts choice in different contexts.
