A study published in the Journal of Retailing and Consumer Services has found that people are significantly more likely to make indulgent purchases in the evening, with online shopping data showing a sharp spike in hedonic buys at 8pm.. The research, conducted by scientists in Australia and China,analyzed nearly 250,000 transactions and also ran a controlled experiment with 200 participants, revealing that the effect is driven by heightened psychological arousal tied to circadian rhythms, not fatigue.

The 8pm peak: how 250,000 transactions revealed hedonic shopping's prime time

According to the study, the number of luxurious or decadent purchases rose sharply at 7pm and hit a peak at 8pm in the analysis of online shopping data. The researchers , writing in the journal, noted that this pattern held across different product categories, including food,entertainment, and personal care items . The timing aligns with natural circadian fluctuations in arousal, which the body’s internal clock regulates throughout the day.

Sixty percent more likely to choose cake at 8pm vs 10am

In a second experiment, 200 participants were asked to imagine choosing between a chocolate lava cake and a bowl of fruit while doing their daily shopping. The group surveyed at 8pm was 60% more likely to pick the cake compared to the group asked at 10am, as the researchers reported. This controlled test reinforces the transactional data and isolates the time-of-day effect from external factors like work stress or exhaustion.

Arousal, not exhaustion: what the body clock study actually found

The scientists explicitly ruled out fatigue as the cause, stating that “the heightened preference for hedonic options in the evening is not driven by fatigue, but rather by the natural rise in psychological arousal.” They explained that hedonic consumption requires overcoming guilt, and the high-arousal state in the evening provides the motivation to justify pleasure-oriented choices. This offers a nuanced alternative to the common assumption that willpower simply wanes as the day goes on.

What the study left out: individual rhythms and real-world caveats

The research did not account for individual differences in circadian typology—morning larks versus night owls—which could shift the tmiing of the effect. Moreover, the transaction data came from a single online platform,limiting generalizability, and the 200-person experiment used a hypothetical scenario rather than real purchases. It also remains unclear whether the arousal mechanism operates identically for online browsing, in-store shopping, or for non-food hedonic items like luxury goods. The study opens a door, but more work is needed to translate the findings into practical advice for consumers or retailers.