Abstract: Uncertain gain is a key factor in promoting blind box consumption. Based on the classification of blind boxes into experience version and koi version, this study explores the psychological mechanism of uncertain gain in enhancing the promotional effect of blind boxes through four psychological experiments. Experiments 1a and 1b compare the promotion effects of the experience version, control group, and koi version blind box, and reveal that the koi version blind box can induce a stronger purchase intention, while the difference between the control group and the experience version is not significant. This indicates that uncertain returns can stimulate strong purchase intention, thereby improving promotional effectiveness. The result of Experiment 2 shows that the expected surprise and purchase intention induced by the Koi version blind box are higher than those induced by the experience version blind box, and the expected surprise plays a mediating role in the influence of blind box form on purchase intention, indicating that the expected surprise caused by uncertainty is an important driving emotion affecting blind box purchase intention. Experiment 3 studies the mechanism by which expected surprise and purchase intention are regulated by uncertainty perception and luck belief. The following conclusions are drawn: firstly, the stronger the uncertainty perception contained in the blind box, the stronger the positive regulatory effect on expected surprise and purchase intention; secondly, the stronger the consumer’s belief in luck, the more significant the positive moderating effect on expected surprises. In order to better protect consumers’ rights and interests, it is suggested that enterprises should strengthen the construction of business ethics while focusing on the design of blind box promotion with the characteristics of uncertain gains, the consumers should correctly understand the value of blind box promotion and learn to consume rationally, and the government should strengthen the supervision of blind box promotion and regulate the behavior of enterprises.

Key words: blind box promotion, uncertain gain, expected surprise, uncertainty perception, luck belief