Oct 19 2021
Published by
NYU Shanghai
People, in general, prefer a sooner smaller reward rather than a later larger reward. However, the degree to which people think it is worth waiting varies, and this is called one's "time preference" or their "discount factor", since we can think of future rewards being delay-discounted.
An interesting question related to this topic is how individual differences in time perception matter for delay-discounting, i.e., do people who perceive 30 seconds as 35 seconds discount the passage of time more steeply?
Researchers from NYU Shanghai have provided new insights into this question by discovering that individual differences in timing have a surprisingly small influence on delay-discounting. The result was published in a recent issue of the journal Scientific Reports. The corresponding author of the research is Professor Jeffrey Erlich, Assistant Professor of Neural and Cognitive Sciences at NYU Shanghai, Global Network Assistant Professor at NYU and a member of the NYU-ECNU Institute of Brain and Cognitive Science at NYU Shanghai.
A previous study from Dr. Erlich and former NYU Shanghai Postdoctoral Fellow Dr. Evgeniya Lukinova has examined how reliable people's time preferences are across time-horizons (seconds vs. days) and across task structure (non-verbal vs. verbal). They found a high correlation in time-preferences across different time-horizons and different tasks. However, a substantial amount of variation was left unexplained.
In this study, Drs. Erlich and Lukinova further looked into the variation which they speculated to be caused by the differences between tasks.
“One major difference between the seconds and days tasks was that subjects had to wait during each delay in the seconds task, but for the days task only one of their choices was randomly chosen and implemented, so they went about their lives waiting for an electronic payment in e.g. a week,” explained Dr. Lukinova, who is the first author of the study, and now an Assistant Professor Faculty Fellow of Statistics at NYU Shanghai . “Our main hypothesis for this study was that variation in time perception may be influencing choices in the seconds task where delays are experienced but not in the days task. In particular, subjects that experienced the delays as longer would appear to discount the passage of time more steeply.”
They employed a novel and powerful way to test subjects in two delay-discounting tasks, only one of which is hypothesized to depend on time perception. Thus, rather than trying to find a link between time perception and discounting directly, they compared time perception to the difference in discounting on the days and seconds tasks.
To the researchers’ surprise, they found only weak evidence for their hypotheses: overall, individual differences in time perception did not influence their time preferences.
“Our result challenged the exiting literature which claims that there is a relationship between timing and delay-discounting. To get a definitive answer, a large multi-site pre-registered study should be conducted,” said Professor Erlich.
More interestingly, Erlich thinks the results may imply that there are multiple clocks in the brain and the one used for timing the duration of stimuli is not the same one that is used to time how long you are waiting for a reward.
The research was funded by the Shanghai Eastern Scholar Program and was supported by the NYU-ECNU Institute of Brain and Cognitive Science at NYU Shanghai.
Journal Reference:
Lukinova, E., & Erlich, J. C. (2021). Quantifying the contribution of individual variation in timing to delay-discounting. Scientific Reports, 11(1), 1-13.