People who reach for extra sugar may also be reaching for certainty, a new study suggests. Researchers at HSE University in Moscow found that a strong preference for sweet tastes correlates with a tendency to avoid uncertain outcomes, even when the choice appears impulsive.
How the experiments were structured
In the first phase, 49 young adults completed the Kampov-Polevoy sweet-preference test, which asks participants to rank solutions of increasing sucrose concentration. Those who chose the most concentrated solution were classified as “sugar-holics.”
Participants then performed the Balloon Analogue Risk Task (BART), a computer simulation where they inflate a virtual balloon to increase a monetary reward. The balloon could pop at any moment, introducing risk without explicit probability cues.
The final task of phase one was a lottery choice exercise. Subjects selected between a guaranteed small reward and a larger, probabilistic one, with the exact odds displayed—for example, a 25% chance at 380 units versus a 100% chance at 100 units.
After completing these assessments, a second group of 100 volunteers repeated the sweet-preference test before tackling a series of delay-discounting trials. In each trial, they chose between an immediate smaller sum (e.g., 50 units) and a larger sum delivered after a delay (e.g., 200 units after one month).
Lead author Anna Davidovich explained the motivation behind the design: “Choosing a smaller immediate reward may stem from a desire to avoid uncertainty rather than a desire to receive the reward as quickly as possible.”
While earlier work linked a sweet tooth to substance dependence, this investigation shifts the focus to decision-making under risk. The finding that sugar-loving participants shy away from ambiguous outcomes mirrors patterns observed in addiction research, where heightened reward sensitivity often coexists with intolerance of uncertainty.
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Phase-one results showed that sweet-preferring participants were less likely to pick the risky lottery option when probabilities were explicit. In contrast, the BART produced no significant difference between sugar-holics and others, suggesting that unknown risk levels may neutralize the effect.
During phase two, the delay-discounting task revealed that sugar-holics opted for the immediate 50-unit reward in 68% of the trials, even when the delayed alternative was four times larger. This preference persisted regardless of the size of the delayed payoff.
When the lottery presented a 50% chance of winning a larger sum, participants with a strong sweet preference gravitated toward the guaranteed smaller payout, indicating heightened caution under maximal uncertainty.
Neurobiological background
The research notes that the brain’s opioid system plays a central role in processing rewarding stimuli. This network of receptors generates pleasure, modulates pain, and contributes to threat detection. Activation of the mu-opioid receptor is linked to feelings of euphoria and analgesia.
Scientists point out that substances such as alcohol indirectly stimulate the same receptor, producing similar pleasurable effects. Prior work has shown a statistical association between a preference for sweet tastes and increased likelihood of substance dependence. This overlap suggests that reward-related brain pathways may influence both sweet cravings and addictive behaviors.
Reward sensitivity, defined as the degree to which an individual is motivated by reward, is described as higher in people with a strong sweet preference. Higher sensitivity can coexist with a reduced tolerance for uncertainty, shaping decision patterns observed in the experiments. The authors propose that overlapping neural circuits could explain why sweet-loving participants display cautious choices when outcomes are ambiguous.
To explore the underlying mechanisms, the investigators examined three possible drivers of delay-discounting behavior. One hypothesis considered heightened sensitivity to reward magnitude, another focused on a preference for immediate gratification, and a third examined aversion to risk arising from uncertainty. The experimental design allowed comparison of these explanations across the two study phases.