The COVID-19 outbreak had a significant negative impact on people’s mental health (Gan et al., 2022). Meaning in life (MIL) was a protective factor that buffered the impact of the epidemic on general health (e.g., state anxiety and COVID-19 stress) and life satisfaction (De Jong et al., 2020; Trzebiński et al., 2020). MIL was defined as “the sense made of, and significance felt regarding, the nature of one’s being and existence” (Steger et al., 2006) and was one of the most fundamental variables that contributed to a pleasant and positive mood (Hone et al., 2014; King and Hicks, 2021). Frankl (1985) proposed that searching for the MIL was the original driving force of human life. Based on Seligman’s (2002) theory of happiness, a meaningful life was the ultimate way to achieve genuine happiness and life satisfaction. Numerous studies have supported beneficial effects of having more MIL on individuals’ positive and negative emotions (Updegraff et al., 2008; Miao et al., 2017; Hooker et al., 2018). For instance, studies showed that having more MIL was closely related to an optimistic attitude toward life (Steger and Kashdan, 2007), more positive social interactions (Steger and Shin, 2010), and increased life satisfaction (Bonebright et al., 2000). On the contrary, having less MIL could lead to one’s negative psychological outcomes, such as depression (Steger et al., 2009), anxiety (Steger and Kashdan, 2007), and even suicidal tendencies (Steger et al., 2008). Therefore, enhancing MIL might be an effective means to improve positive affect (PA) and reduce negative affect (NA).

Earlier studies used self-report measures to assess MIL at a certain time point (Peterson et al., 2005; Steger and Shin, 2010). Given that the previous method was hard to deeply get one’s overall sense of meaning because of a lack of dynamic evaluation of experiencing and living in life, Steger et al. (2013) developed a visual research method of photographic intervention to assess one’s MIL and tested its effectiveness on positive and negative affects. The photographic intervention was constructed from the perspective of improving individuals’ cognition and emotional evaluation of life’s purpose and sense of value (Steger et al., 2013, 2014). In the 1-week intervention, participants were asked to take photos that made their lives meaningful, and then described the significance of all these photos at the end of the week, and the results indicated that photographic intervention promoted individuals’ MIL that was significantly related to increased PA, increased life satisfaction, and reduced NA (Steger et al., 2014); however, asking participants to describe all the pictures a week later might cause memory burden and biases (Steger et al., 2014; Miao and Gan, 2019). Even more, the lack of a control group in Steger et al. (2014) made it impossible to exclude other factors’ potential effects. Therefore, the present study was designed to retest the effect of photographic intervention on positive and negative affects during COVID-19 by adding a control group and asking participants to write a description of the photo in time.

Although current evidence has proven the positive effect of photographic intervention on individuals’ emotions, the underlying mediation mechanism remains to be further explored. Our study speculated that future self-continuity (FSC) might play a mediating role between MIL and PA/NA. FSC meant the connection between one’s present self and future self, and it was a key component of a global self-continuity or a stable identity (Van Gelder et al., 2013). FSC was closely related to behavioral outcomes, such as more financial saving behaviors, greater academic achievement, less delinquent behaviors, and healthy exercise behaviors (Ersner-Hershfield et al., 2009; Van Gelder et al., 2013; Rutchick et al., 2018). This might be because individuals with higher FSC were more likely to see the future as hopeful and attainable, and to have the willingness and ability to engage in adaptive behaviors in the present for achieving an obtainable future self (Sokol and Serper, 2019). First, Baumeister et al. (2013) stated that one of the most critical functions of MIL was temporal integration of the past, present, and future. Research indicated that seeking and discovering a meaningful life was linked with the ability to maintain and enhance the self-continuity between the present and the future (King and Hicks, 2021). Second, increased FSC contributed individuals to constructively processing negative life events, such as adopting a broader temporal perspective to reduce self-esteem declines (Wink and Schiff, 2002; Sokol and Serper, 2019). The research results indicated that individuals with more overlapping between present self and future self were more prone to positively view their future (Zhang and Aggarwal, 2015) which could directly bring positive emotions (Bryant, 2003), high levels of FSC improved PA and life satisfaction (Sokol and Serper, 2019), while low levels of FSC were strongly associated with NA and suicidal ideation (Sokol and Eisenheim, 2016; Sokol and Serper, 2017, 2019). Third, Terror Management Theory (TMT), based on existential psychodynamic tradition, indicated that one’s death was always potentially imminent and inevitably in conflict with motivational systems geared toward continued life, thus triggering personal anxiety (Greenberg et al., 2008). During COVID-19 epidemic, individuals might experience psychologically the fear related to death. Frankl (1985); Becker (1973) stated that over time, the perception of self-identity and continuity of meaning psychologically protected individuals from the awareness of death threats. Studies results showed that mortality salience led high self-concept structure seekers to prefer causal consistency of recent experiences and meaningful connections between past events and the current self (Landau et al., 2009). Therefore, the continuous search for MIL can maintain self-identity in temporal self, inspiring one’s positive expectations for the future life and alleviating negative emotions. Based on the above research and theory, MIL could improve emotion by the mediating role of FSC.

The present study aimed to explore the effect of photographic intervention based on MIL on college students’ positive and negative affects, and FSC, and whether FSC played a mediating role between MIL and emotions. The photographic intervention, as a MIL-based approach, could draw attention to current life experiences and continuous recording of meaningful life events. Through the constant searching for meaningful information about life, people developed a continuous and uninterrupted identity about their lives, that was, they drew a close connection between their present and future lives (higher FSC), which improved their emotions. We proposed three hypotheses: (a) The MIL-based photographic intervention would enhance participants’ MIL; (b) The intervention would increase the levels of PA and FSC, and mitigate the level of NA; and (c) FSC would mediate the relationship between MIL and PA/NA. In our study, a control group was added, and the participants in the intervention group were asked to complete a 14-day photographic intervention, and they were required to upload photos and describe the content of the photos to reduce the memory burden and memory bias.

In order to overcome the shortcomings of previous study (Steger et al., 2014), our study added a control group and increased the frequency of photography. Through a 2-week intervention, we verified that photographic intervention based on MIL promoted PA and reduced NA, and that FSC played a mediating role between MIL and PA. Consistent with previous findings (Steger et al., 2014; Miao and Gan, 2019), our study demonstrated that photographic intervention was an effective way to improve emotions during COVID-19.

FSC was explored as an acting mechanism between photographic intervention and PA in the present study. First, we found that photographic intervention increased individuals’ FSC, demonstrating the conducive effect of MIL on FSC. This finding was in line with previous studies (Rubin et al., 2016, 2019) positing that individuals with a high sense of current life experiences tended to exhibit a psychological state that was more closely connected with the future, and that individuals with a low sense of life experience could only isolate the current meaningful life and cannot connect well with future self (Rubin et al., 2016). The photographic intervention guided participants to express the meaning of the photographs coherently and to gain a deeper understanding of their own daily lives, and the coherent expression gave meaning to life transformation and achieving self-continuity (Hong et al., 2021; King and Hicks, 2021). Thus, over time, the experience of MIL might gradually deepen one’s perception of the connection of present self and future self. Second, the sense of self-continuity might play a crucial role in guiding emotional responses (Sadeh and Karniol, 2012), and increasing self-continuity could enhance subjective well-being by shifting to a broader temporal perspective (Sokol and Serper, 2019). Therefore, photographic intervention used a coherent expression of a meaningful life to achieve self-identity in time, generate psychological pleasure, and improve their overall satisfaction with life. This meant that individuals with a higher awareness of MIL could establish a closer connection with the future, thereby enhancing the positive affect on their overall life. As expected, our results confirmed the mediating role of FSC between MIL and PA.

However, we found that FSC did not play a mediating role in this relationship between MIL and NA. Taking photos could be a clear record of a meaningful life, and expressive writing helped to transform abstract MIL (generated from photos) into a narrative and emotional (usually positive) language (Steger et al., 2014; Miao and Gan, 2019). Thus, photographic intervention enhanced primarily positive emotion in our study. According to the “Undoing Hypothesis,” based on the Broaden-and-Build theory (Fredrickson et al., 2000; Fredrickson, 2001), experiencing positive affects can “eliminate” or “undo” the negative effects of experiencing negative affects (Pezirkianidis et al., 2016). As a result, the mediating effect of FSC between MIL and NA did not reach significance in the present study. Future study should explore the photographic intervention aimed to reducing NA, and reexamine the mediating role of FSC.

Our study had several implications. Photographic intervention focused on increasing MIL contributed to an individual’s emotions and well-being. During COVID-19, MIL should be constructed in a variety of ways to increase PA and reduce NA. In addition, improving an individual’s MIL through photographic intervention led to an increasing of FSC, in turn, enjoying a whole and positive life. Previous findings suggested that interventions aimed to increase self-continuity could promote an individual’s self-concept and subjective well-being (Sokol and Serper, 2017, 2019). Attention should be paid to improving individuals’ FSC to promote emotional regulation during COVID-19.

There were some limitations in our study. First, the participants were from a university. One should be cautious about generalizing our findings to other groups. Second, the sources of college students’ MIL might be diverse. In future research, the intervention effects of different types of MIL should be investigated to develop more effective intervention programs. Third, this study did not provide dynamic measurements of intervention effects. In future studies, researchers could adopt an experience sampling method to collect immediate data to examine the effectiveness of photographic intervention.

The original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding author.

The studies involving human participants were reviewed and approved by the Ethics Committee of Henan Province Key Laboratory of Psychology and Behavior. The participants provided their written informed consent to participate in this study.

FZ and YP contributed to conception and design of the study. YP and XL organized the database, performed the statistical analysis, and wrote the first draft of the manuscript. All authors contributed to manuscript revision, read, and approved the submitted version.

This project was supported by the National Social Science Fund of China (No. 18BSH112).

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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