**4. Discussion**

Based on the self-reported data in China during the COVID-19 pandemic and the objective risk level of each region given by official authority, this study tested the mediating effect and moderating effect hypotheses mentioned above. The results support all our hypotheses. Firstly, the results suggested that the mediating effect of perceived control on the relationship between social class (both objective and subjective) and need for structure is significant; thus, social class negatively predicted need for structure and this association was partially mediated by perceived control. Specifically, the lower an individual's social class is, the lower his or her sense of control is, and, therefore, the higher his or her need for structure tends to be. Furthermore, the results also showed that pandemic threat moderated the relationship between perceived control and need for structure, and the relationship between social class and need for structure, finally leading to the moderated mediating effect. Under the condition of higher pandemic threat, individuals with higher perceived control increased their need for structure significantly, so the predictive effect of perceived control on need for structure was no longer significant. Similarly, under the condition of higher pandemic threat, individuals of higher social class increased their need for structure significantly, so to the predictive effect of social class on need for structure was no longer significant. Finally, the results showed the moderating effect of pandemic threat on the mediating model of "social class → perceived control → need for structure". Therefore, all the hypotheses of this study were supported.

Previous studies tended to regard the need for structure as an independent variable and to examine its predictive effect on other psychological outcomes [45,46]. Conversely, few studies have taken the need for structure as a dependent variable and focused on the factors influencing it. Although the need for structure can be regarded as a relatively stable personality trait, it can also be influenced by other individual and environmental factors [47,48]. Especially in the context of uncertainty, need for structure can be regarded as the psychological basis of many psychological and behavioral factors, such as conspiracy theory thinking [49] and stereotyping [23]. It is meaningful to pay attention to need for structure and its influencing factors under the pandemic conditions. Accordingly, this study first examined the predictive effect of social class on need for structure, and found that people of lower class tend to develop a higher level of need for structure due to their relatively lower perceived control. This conclusion supports an expansion of previous research. Previous studies have found that social class positively predicts perceived control [21,29], while perceived control negatively predicts need for structure [30,31]. Although a previous study directly investigated the relationship among the three variables [7], it focused only on the student samples and the effect of subjective social class. The present study provides more solid evidence for this mediation model by using a sample of non-student adults from different provinces in China. This result more directly reveals the difference in need for structure among people of different social classes and the psychological mechanism underlining their lack of control. Compensatory control theory proposes that when personal control is threatened, individuals are more inclined to seek structure to compensate for personal control [6,11]. The results of this study show that people of lower class are more likely to feel the lack of control and then develop compensatory control, which has enlightenment value for the development of compensatory control research in the future.

In addition, this study's most important finding is the moderating effect of pandemic threat. This phenomenon suggests that for individuals who generally lack one kind of motivation (e.g., the need for structure), it is more likely for them to be provoked by a threat (e.g., the COVID-19 pandemic) and the particular motivation of them will increases even more significantly. Similar views have been proposed and supported by previous studies [33–35] and the present study supplements the conclusions of this kind of research. At the same time, the results also support the cognitive motivation model of stress. This model suggests that an important aspect of the psychological impact of stress and threat is the increased desire for certainty [32], which is consistent with the conclusions regarding the need for structure made in the present study. We also found that, when faced with the threat of COVID-19, even those from higher classes (and who had a higher sense of control) experienced an increase in their need for structure, order, and certainty (though they did not in their normal state). This showed a cross-group consistency in psychological needs during the pandemic.

Why do individuals who normally deal better with uncertainties (individuals of higher class and with higher perceived control) experience the greater impact of the pandemic threat? We believe that it is necessary to distinguish their demonstration of the general state and the crisis state. In general, individuals of higher social class (and usually with a higher sense of control [21]) command more social resources, which can support them to cope with the challenges of normal life [26]. In contrast, lower-class individuals are less capable to deal with environmental threats due to a lack of resources, and, therefore, are more in need of certainty and order [7]. Under the condition of a new kind of threat (the COVID-19 pandemic), however, the upper-class individuals feel a threat that differs from the ones they face in their daily lives, which leads to a significant increase in their need for structure and avoidance of uncertainty. The threat of the pandemic has a lower impact on lower-class individuals, perhaps because they have been accustomed to threats from various domains. Therefore, instead of saying that the threat of the pandemic affects upper-class individuals more, it can also be interpreted as the unequal distribution of "normal" uncertainties and threats across different classes in daily life.

This study presents three theoretical implications that may provide some insight for the future research. First, the study observed that lower personal control is not the only source of the need for structure. On the contrary, people with a higher sense of control may also have a relatively high need for structure under certain conditions, such as the threat of a pandemic. Therefore, researchers of compensatory control theory need to further investigate the boundary conditions of the compensatory control model. Second, in terms of the need for structure, although this variable is usually regarded as a relatively stable personality trait [42], our study revealed that this basic need fluctuates under certain conditions. We found that the interaction of individual factors (social class, personal control) and environmental factors (pandemic threat) significantly predicted the need for structure. This suggests that future research on the need for structure should focus on the interaction effect between individual and environmental factors to comprehensively reveal the factors influencing this need. Third, this study adopted two operational definitions for the measurement of social class, that is, objective social class and subjective social class, and the effects were shown to be almost identical. Previous studies have found that the two have different effects on the prediction of some dependent variables [50]. For example, some studies found that subjective class positively predicts individual's support for social system, while objective class is negatively correlated with system support [51,52]. In the present study, however, the effect of subjective class was almost the same as that of objective class, and together their effects supported all our assumptions. On the one hand, this reflects the stability of the conclusions of our study. On the other hand, it also shows that the concepts of subjective class and objective class still have a certain commonality and relevance.

In addition, this study also has some practical significance. The COVID-19 outbreak has greatly affected the way we think and live. At the same time, economic inequality, environmental problems, new technology, and many other factors have left the world in a state of uncertainty. The results of this study highlight that when faced with the threat and stress of a pandemic, people prefer to pursue a structured, orderly, and predictable life and do not want to face the random, uncontrollable, and changing physical and social environment. Moreover, even higher social class groups will have more needs and preferences for order and structure in the context of an epidemic or pandemic. Therefore, in the midst of the current pandemic, governments should consider whether their pandemic management policies meet the public's need for structure and aim to maximize citizens' sense of structure and order. Moreover, due to the consistency in the need for structure among the upper and lower social classes in the context of the pandemic, policy makers must also ensure the interests and security of both higher- and lower-class groups without distinction.

Finally, this study has some limitations, which should be investigated in future research to conduct a deeper exploration of the topic. First, the sample was derived only from China and was investigated in the context of small COVID-19 outbreaks in several Chinese provinces in July and August 2021. China's pandemic-prevention policy is relatively stricter [17], and Chinese individuals exhibit higher levels of collectivism when facing the pandemic and the related policy measures [53]. Thus, Chinese individuals' psychological response to COVID-19 may be influenced by certain unique sociocultural factors. Therefore, the behaviors of people in other countries and regions should be investigated in the future to test the conclusions of the present study. Second, since students and individuals who chose the wrong risk level of their residential area were excluded from this study, the representation of the present study findings may be slightly inadequate. Although this may not have affected the main conclusions of the present study, future research should include more representative samples. Third, our study's conclusions rely on crosssectional data, and the investigation of the relationship between variables was based on the correlation method, which cannot provide strong proof of a causal relationship. Consequently, alternative methods rooted in experimental design should be considered in future research to further verify the model and effects observed in this study, such as implicit-mediation analysis [54]. In addition, implementing longitudinal design is also a feasible way to test the robustness of the conclusions. Fourth, the present study only focused on the moderating effect of the threat of COVID-19. However, threats come from many sources in real life. Do all threats result in this effect? This question should also be examined in more complex studies in the future. Finally, the measurement of the participants' occupation may not accurately describe the reality rank of some participants. Although the problem may be minor, it needs to be acknowledged. Future research can explore more ways to assess an individual's objective social class.
