Why can’t I resist shopping at night? I finally found the reason!

"Double 11" is about to kick off. Under the guidance of advertising and promotional mechanisms on shopping platforms, consumers have begun to carefully select their favorite products and place orders. They may be able to make rational selections during the day, but at night they are easily tempted to want this and that, and finally regret it secretly when they see a pile of express deliveries.

This is not an isolated case. There are obvious differences in cognitive abilities or behavioral decisions between individuals during the day and at night . For example, in life, people may prefer a fixed combination like "soy milk + fried dough sticks" in the morning, but have more demands for dinner, such as fried chicken, noodles or other foods; or they may maintain stronger alertness during the day, but have a higher tendency to take risks at night, such as gambling and high-risk investment behaviors.

These seemingly unrelated phenomena actually contain the same explanatory mechanism behind them, which is the circadian rhythm effect . Circadian rhythm can not only regulate an individual's sleep pattern , it can also regulate an individual's psychological activities and behavioral patterns . Specifically, at different times of the day, the body's physiological mechanisms will show different levels of activity, which in turn significantly affects people's subjective perception and cognitive ability . Circadian rhythm guides individuals to respond to their current physiological state at specific times in the morning and evening by adjusting variables such as the individual's physiological arousal level and self-control ability, so as to adapt to the needs and challenges of different time periods and satisfy their own feelings.

1. Differences in day and night time affect consumer behavior decisions

In recent years, the night economy has gradually occupied the main market. Different from the new consumption characteristics during the day, the day and night time has gradually become a hot research topic in the field of consumer behavior. In 2019, Professor Gullo from Duke University took the lead in systematically proving the existence of day and night differences in consumer behavior through data analysis and laboratory experiments [1]. Through empirical analysis of the supermarket shopping behavior of more than 1 million households for 25 consecutive months, he verified that the behavior of seeking variety has a circadian effect, that is, it changes with the time of day. People have less diversity in their shopping choices in the morning, which increases during the day and gradually flattens out in the afternoon.

The circadian rhythm effect has also been widely used in other consumer behavior studies and has been repeatedly verified. More importantly, the "morning morality effect" theory proposed by Professor Kouchaki of Harvard University states that people's self-control resources will gradually be depleted during the day, and their self-control ability will gradually weaken. People are more likely to engage in unethical behavior in the afternoon than in the morning [2]. This provides a scientific basis for the increase in unethical consumer behaviors such as malicious reviews and refunds that consumers may experience during specific time periods (such as evening).

This pattern of day-night differences in consumer behavior shown in the above studies can be explained at a deeper level from the perspective of optimal stimulus level theory and self-control theory .

2. Diversity of circadian behavior: changes in optimal stimulation levels

The optimal stimulation level theory holds that individuals tend to maintain the stimulation level at the optimal state . If the stimulation level received by an individual is lower than the optimal stimulation level, the individual will feel bored and desire to increase the intensity of stimulation. On the contrary, the individual will tend to reduce or simplify the external stimulation input to maintain a relatively stable or comfortable stimulation environment [3]. The individual's physiological arousal level determines the level of external stimulation that the individual expects. Physiological arousal refers to the corresponding physiological reactions that occur when an individual's emotions and feelings change, such as increased body temperature and faster heart rate when an individual is emotionally excited.

Professor Gullo demonstrated the mediating role of physiological arousal levels through an experiment. They randomly assigned subjects to take a highlighter purchase test at different times of the day, asking them to randomly select 6 highlighters from 6 colors, using the uniqueness of the highlighters they chose to measure their level of diversity seeking, and measured their body temperature to measure their physiological arousal level [1]. Through the experiment, they proved that individuals have low physiological arousal levels in the morning and have a lower optimal stimulation level . At this time, in order to avoid receiving too much external stimulation, individuals are more likely to seek less diversity when shopping or choosing in the morning.

Although the optimal stimulation level theory provides theoretical evidence for some behaviors of consumers, there are still some day and night differences in behavior that are difficult to explain and urgently need new theoretical explanations.

3. Behavioral loss of control under circadian rhythm: the limits of self-control

Behaviors such as overeating and overspending are true reflections of self-control failure in reality, and self-control failure provides a new way to explain behavioral differences such as consumer unethical behavior and changes in product preferences. Self-control theory holds that individuals change their behavior, feelings, and thoughts through self-control [4].

Existing research has shown that self-control has a diurnal cycle pattern . Individuals often have sufficient self-control resources in the morning, but face frequent choices throughout the day, which continuously consumes their self-control resources. Finally , they face self-depletion at night, at which time individuals are more likely to succumb to temptation and engage in more primitive and impulsive behaviors .

In recent years, scholars have confirmed the mediating mechanism of self-control failure in the circadian rhythm effect from different perspectives. In 2022, some researchers divided media content into virtue content and vice content, using Twitter data as a research case. The experiment proved that as Twitter users' self-control levels gradually decreased throughout the day, their reading preferences would gradually shift from virtue content to vice content [5]. Other researchers focused on consumers' purchasing preferences for health products, and used laboratory experiments and eye tracking experiments to prove that self-control mediates the mechanism of consumers' purchasing preferences for health products at different times of the day: at night, when consumers face the situation of self-control failure, they will pay more visual attention to unhealthy products, thereby consuming more unhealthy products [6].

IV. Conclusion

The proposal of the circadian rhythm effect provides a new explanation for the differences in individual day and night behaviors. The morning and evening differences in individual behaviors are not only affected by the circadian rhythm , but also regulated by the individual's optimal stimulation level and self-control ability.

Considering the circadian rhythm effect in marketing can provide more targeted and scientific theoretical guidance for the timing and method of advertising. If we pay attention to the circadian rhythm effect in daily life, it will help individuals pay attention to and control their own behavior in the morning and evening, and make more rational choices and decisions .

In short, the circadian rhythm effect, as a new perspective in psychological research, has certain important significance for the development of individuals, enterprises and other organizations, and can be further explored in different academic fields in the future.

References:

[1] Gullo, K., Berger, J., Etkin, J., & Bollinger, B. (2019). Does Time of Day Affect Variety-Seeking? Journal of Consumer Research, 46(1), 20-35.

[2] Kouchaki, M., & Smith, IH (2014). The Morning Morality Effect: The Influence of Time of Day on Unethical Behavior. Psychological Science, 25(1), 95-102.

[3] Menon, S., & Kahn, BE (1995). The Impact of Context on Variety Seeking in Product Choices. Journal of Consumer Research, 22(3), 285-295.

[4] Muraven, M., Tice, DM, & Baumeister, RF (1998). Self-Control as Limited Resource: Regulatory Depletion Patterns. Journal of Personality and Social Psychology, 74(3), 774-789.

[5] Zor, O., Kim, KH, & Monga, A. (2022). Tweets We Like Aren't Alike: Time of Day Affects Engagement with Vice and Virtue Tweets. Journal of Consumer Research, 49(3), 473-494.

[6] Yang, S., Wang, Y., Li, Z., Chen, C., & Yu, Z. (2022). Time-of-day effects on (un)healthy product purchases: Insights from diverse consumer behavior data. Journal of Business Research, 152, 447–460.

(Authors: Chen Xueping and Li Ou, Alibaba Business School, Hangzhou Normal University.)