Fang Yingying, Associate Professor at the School of Economics, Beijing Business and Technology University. Richard Seiler, a Nobel laureate in economics in 2017, proposed the concept of "psychological accounts" when studying human behavior. Just like how governments and businesses prepare budget tables, consumers often have such a table in their hearts, either simple or complex, dividing them into different categories. Under the assumption of traditional rational economic agents, consumers are only limited by the total budget. As long as the total amount remains unchanged, whether the money is placed in the left or right pocket will not change consumer behavior, but the psychological account theory tells us a different answer. If you have already purchased some clothes earlier this month, when you come across another beautiful piece of clothing while shopping, you may stop buying because you have spent too much on clothing before; But if this money is used to pay for a favorite performance, many people will not hesitate, because clothing purchases and entertainment expenses clearly belong to different accounts, and their budgets cannot replace each other. Similarly, income from different sources can also lead to different consumption tendencies. For example, if an additional income is earned at the end of the year due to a salary increase, most people tend to deposit the remaining amount into a savings account after spending a portion of it; But if this money comes from lottery or annual lottery, it may be more used for consumption, especially for some enjoyment related expenses. The same consumer product may also lead to different psychological accounts in different scenarios. When a family goes out for a weekend dinner, they may prioritize choosing a restaurant that is close to home and offers high value for money; If a friend visits from another city, they tend to look for restaurants with comfortable and distinctive environments. Similarly, for food and beverage expenses, in the psychological account, the former belongs to the category of "clothing, food, housing, and transportation" in daily life, while the latter can be included in the "human relations" account, and people are willing to pay a higher price for it. Just like using a ledger for bookkeeping, psychological accounts also require regular accounting. Different groups of people tend to have different time intervals, which is certainly due to individual habits and is largely influenced by the total amount of wealth. When I was still a student, I usually reviewed my monthly expenses because I received living expenses from my parents for daily expenses, so I planned my expenses on a monthly basis. But after work, the time interval for regular reviews becomes longer, and the sense of urgency for reviews decreases. Generally, one only reviews their past year's expenses at the end of the year. Daily expenses are trivial, and even with accounting habits, it is not possible to record every expense in detail. At this time, some non regular small expenses are easily overlooked. For example, buying a bottle of mineral water due to thirst when going out, or spending parking fees when shopping at a mall. As a result, many advertisements coincidentally use language similar to "only 1 yuan per day" to try to include these expenses in overlooked small payments, thus breaking free from the constraints of psychological accounts and unknowingly spending money. With the development of economy, our consumption habits and consumption structure are changing quietly. The emergence of consumption keywords such as "Yueji", "Pingdai", "Green" and "China-Chic" shows that the classification of everyone's mental accounts and the distribution of budget expenditure are also