Sugar Liking as a Common Indicator of Impulsivity in Delay Discounting and Risk Taking Tasks

Both risky and intertemporal choices involve reward valuation. Monetary choices people make when risk or time delay is present might be linked to individual reward sensitivity. Previous studies indicated that people with high preference for rewarding stimuli (e.g., sucrose) also demonstrate increased impulsivity, i.e. tendency to choose smaller immediate over larger delayed rewards. However, as time delays are inherently associated with increased risks this link might be potentially modulated by individual risk preferences, with higher risk aversion leading to preference for immediate over delayed reward. In this study, we use the sucrose solution liking test as an indicator of reward sensitivity to test two hypotheses – first, that reward sensitivity is linked to risk preferences, and second, that this link might modulate the association between reward sensitivity and impulsivity. Regression analysis revealed that sweet-likers were more sensitive to the time delay compared to sweet-dislikers – increasing the delay by one day increased the probability of choosing an immediate option significantly more for the sweet-likers group compared to sweet-dislikers. Further analysis revealed that this effect was explained by differences in risk preferences. Sweet-likers were significantly more risk averse compared to sweet-dislikers. Accounting for participants’ risk preferences in the analysis of delay discounting choices eliminated the effect of sweet-liking on impulsivity.