Abstract: The effect of social media on executive functions remain controversial. Some studies have shown that the use of social media promotes an individual's executive functions, and some studies have found that social media use has a negative impact on executive functions. Recent studies have shown that, there may be an inverted U-shaped relationship between social media use and individual's executive function, and that social media use does not necessarily impair or promote executive function, but there is an optimal tipping point between the two. Moderate-intensity use of social media is the best level to promote executive functions. This is related to the moderating role played by the intensity of use. The paper first introduces the behavioral evidence that the effect of social media on executive functions, including three parts: positive effects, negative effects, and inverted U-shaped relationships. Secondly, it analyzes the moderating effect of intensity of use in the inverted U-shaped relationship between social media use and executive functions, and attempt to reveal the debate over the pros and cons of social media use on executive functions. Moderate-intensity use of social media will produce a social media flow experience, allowing individuals to filter out various distracting information when faced with various complex information stimuli in social media, focusing on useful information, and target information is constantly being affected. With storage and update, the individual's executive functions (especially the shifting function) get long-term and repeated exercise under such requirements, and finally improve. In addition, the flow experience generated by the use of social media can be used as an intrinsic motivation to increase the interaction of social networks to make positive changes in interpersonal relationships. This provides individuals with continuous social rewards and emotional support. To a certain extent, it buffers the negative impact of excessive use of social media on cognitive function, and slows down the decline of age-related executive functions. However, high-intensity use of social media causes individuals to worry about their performance in the task, which tends to maintain a wider range of attention and is more susceptible to interference from irrelevant information, while low-intensity use of social media causes individuals to be in a state of lack of proactiveness, the psychological effort process of information processing is reduced or even disappeared, which has a negative impact on executive functions.
Future research in this area should examine the dose-effect of social media use affecting executive functions. The positive impact of social media use on the executive function may require a relatively long and continuous process of using social media. Whether an optimal social media can be determined the level of media usage maximizes individual's executive functions? In addition, previous research mainly focuses on the impact of social media usage frequency on individual's executive functions in daily life, but lacks a single sub-component of the type of social media usage on the executive function investigation of development and changes. In the future, the relationship between different types of social media usage and sub-components of executive function should be further clarified. Finally, the lifting effect of social media may be more significant in groups whose brain structure is in a period of change. Most previous studies only show that the use of social media can change individual's neural pathways or brain response patterns (and little is known about whether changes in the physiological structure of executive function have an impact on the cognitive level of social media users. Future research should combine behavioral and cognitive neurological methods to examine the brain regions of social media users with different cognitive levels in performing specific tasks. The difference in activation makes the neural mechanism of social media use affecting executive function more precise and comprehensive.

Key words: social media, executive function, flow experience