One of the exercises in the 6-Minute Diary is a classic gratitude intervention in which one lists things or events for which one is grateful (Emmons and McCullough, 2003; Watkins et al., 2003; Seligman et al., 2005; Froh et al., 2008). To date, several studies have examined the benefits of gratitude for interpersonal relationships (Sun et al., 2014), social support (Wood et al., 2008), subjective well-being (Wood et al., 2009; Rash et al., 2011; Allan et al., 2013; Datu, 2013), strengthened social relationships (Emmons and McCullough, 2003), and improved physiological and cognitive functioning (McCraty et al., 2003). There are positive correlations between gratitude and life satisfaction, happiness, optimism, hope, and positive affect. Furthermore, there are negative correlations between gratitude and anxiety, depression, negative affect, and physical aggression (e.g., McCullough et al., 2002; Watkins et al., 2003). These results indicate the potency of gratitude as an amplifier for positive emotions and a buffer for negative emotions.

Another exercise of the 6-Minute Diary is setting positive, personal goals. These goals reflect consciously formulated and personally meaningful objectives that guide perceptions, feelings, thoughts, and actions (Elliot et al., 2001; Wiese and Freund, 2005). Conscious goal setting is intended to direct attention and effort toward goal-relevant activities and away from goal-irrelevant activities (Locke et al., 1981).

There are negative correlations between goal-setting interventions and negative affect, and positive correlations with positive affect (Emmons and Diener, 1986), subjective well-being (Brunstein, 1993), and higher expectancy of success (Karakowsky and Mann, 2008). The mere existence of self-set goals seems to correlate with well-being as much as the actual achievement of the goals (Emmons and Diener, 1986). Furthermore, there is evidence for a positive influence of goal setting on perceived self-efficacy (e.g., Latham and Seijts, 1999).

The principles of self-affirmation are also echoed through a 6-Minute diary exercise in which users write a positive phrase about themselves each morning. These phrases are designed to help identify and reinforce one’s core values (Steele, 1988; Sherman and Cohen, 2006).

Regular self-affirmations have been shown to reduce negative emotions (Nelson et al., 2014), moderate physiological responses to stressful situations (Creswell et al., 2005; Sherman et al., 2009), and increase self-efficacy expectations, positive affect (Howell, 2017), and academic achievement (Cohen et al., 2006, 2009).

Another exercise in the 6-Minute diary draws on the principles of random acts of kindness (Jones, 1998). Individuals are asked to remember what good they have done for others that day. Being aware of one’s acts of kindness shows a positive association with well-being (Otake et al., 2006; Lyubomirsky and Layous, 2013), self-worth (Fredrickson et al., 2008), positive affect, experienced social support, and mindfulness, and a negative association with negative affect and symptoms of illness (Fredrickson et al., 2008; Cohn and Fredrickson, 2010; Hoffman et al., 2011).

The Three Good Things intervention involves writing down three things that went well each day while consciously focusing attention on positive emotions of the day (Seligman et al., 2005). Implementation of the intervention showed a positive association with experiencing positive emotions (Lyubomirsky, 2008), positive affect, gratitude (Martínez-Martí et al., 2010), and well-being, and a negative association with depressive symptomatology (Seligman et al., 2005) and burnout (Adair et al., 2020).

How individuals perceive and cope with stress varies from person to person; however, short- to medium-term stress often results in physiological activation, impairment of well-being, and reduced performance (Kaufmann et al., 1982). In contrast to medium- to long-term stress exposure, this is not directly detrimental to health (Werdecker and Esch, 2019). Consequences of prolonged stress include elevated blood pressure, cardiovascular disease, or psychological disorders, such as depression or anxiety disorders (Klein et al., 2016; O’Connor et al., 2021). In addition, perceived stress is associated with lower life satisfaction (Matheny et al., 2008).

Therefore, in order to avoid or reduce health-damaging consequences of stress, the development of preventive measures is of particular importance. Behavioral prevention strategies focus on enabling individuals to deal with stressful situations. This can be done by expanding existing resources or developing new coping mechanisms. According to findings in the literature, positive emotions (Folkman, 2008; Layous et al., 2014), gratitude, and confidence in particular (Seligman, 2012), facilitate coping with stress.

Furthermore, increasing resilience and self-efficacy expectations can contribute to better coping with stress (Wiley et al., 2017; Werdecker and Esch, 2019). With the Gratitude Intervention, Three Good Things, and Self-Affirmation exercises, the 6-Minute Diary includes several evidence-based brief interventions that could be effective as behavioral prevention against perceived stress.

There are correlations of positive affect with resilience, social activity, satisfaction, and the number of pleasant events, and correlations of negative affect with stress, health problems, and the number of unpleasant events (Watson and Tellegen, 1985; Watson, 1988; Montero-Marin et al., 2015). Fredrickson’s (2001) broaden-and-build theory suggests that positive emotions lead to an expanded repertoire of thinking and action alternatives, which in turn promote the building of resources relevant to success. Experimental evidence suggests that induced positive emotions, compared to neutral and negative states, increase the range of attention (Rowe et al., 2007) and thereby the possibility for more perceived subjective well-being (Fredrickson and Joiner, 2002).

Experimental research showed that gratitude interventions (McCullough et al., 2002), goal setting (McCarthy et al., 2010), remembering random acts of kindness (Fredrickson et al., 2008), and the Three Good Things intervention (Martínez-Martí et al., 2010) were associated with increased positive affect. This is supported by a recent review of the effect of positive psychology intervention on positive emotions (Moskowitz et al., 2021). For this reason, the use of the 6-Minute diary could also involve an increase in positive affect. Negative correlations have already been found between the intensity of negative affect and participation in a gratitude intervention (Emmons and Diener, 1986) and a Random Acts of Kindness intervention (Hoffman et al., 2011). For this reason, it is reasonable to speculate that the 6-Minute diary may also lead to a reduction in negative affect.

A positive attitude of expectation and the subjective conviction to overcome future demands due to one’s own abilities makes self-efficacy a resource in coping with stress (Bandura and Locke, 2003; Schönfeld et al., 2016). Stressful situations produce less subjective stress in individuals with high self-efficacy than in individuals with low self-efficacy (Flammer, 2015). Higher levels of self-efficacy may be protective against post-traumatic stress (Gallagher et al., 2020) and are associated with lower social anxiety and depressive symptoms (Singh and Bussey, 2011). Furthermore, there are positive associations with increased cognitive performance, motivation (Niemiec and Lachowicz-Tabaczek, 2015), overall life satisfaction, subjective well-being, and optimism (Luszczynska et al., 2005; Sica et al., 2015; Schönfeld et al., 2016).

Self-efficacy is closer to a state than a trait on the spectrum between state and trait and thus changeable within reasonable time and smaller interventions, i.e., can be learned and trained (Luthans et al., 2007; Schönfeld et al., 2016). Self-efficacy is mainly influenced by experiences from four domains (e.g., Bandura, 2000); accordingly, strategies to increase it can also be divided into these domains: (1) Experiences of success: successful attempts in performing certain activities; (2) Model learning: observing successful people who are similar to oneself; (3) Verbal persuasion: other people’s assessment of one’s own ability; and (4) Interpretation of physiological and emotional states: reinterpreting physical states (e.g., trembling, blushing, clammy hands) that are often perceived as signs of failure.

There are several exercises in the 6-Minute diary that are useful for building self-efficacy. Formulating positive goals (“What would make today wonderful?” and “What will I do better tomorrow?”) leads individuals to take on new challenges, providing opportunities to experience a sense of accomplishment. The Three Good Things intervention allows for reflection on those experiences of success and has already been used as an effective means of increasing self-efficacy (Guo et al., 2020).

Empirical research has demonstrated that resilience is closely related to well-being (Ryff, 1989; Keyes et al., 2002; Keyes and Grzywacz, 2005). Evidence suggests that resilience has an impact on positive affect, physical health, sense of purpose, optimism, life satisfaction, and mindfulness (Montross et al., 2006; Lee et al., 2008; Smith et al., 2008; Abolghasemi and Varaniyab, 2010; Huppert and So, 2013; Keye and Pidgeon, 2013). Furthermore, evidence shows a moderating effect of resilience on depressive symptom severity, as well as negative correlations with depression, negative affect, pessimism, and emotion blindness (Smith et al., 2008; Wingo et al., 2010).

Strategies to increase resilience can be divided into three groups with different emphases: risk-, resource-, and process-oriented (Masten et al., 2009), with the former being mainly relevant in a developmental psychology context (Luthans et al., 2007). Resource-oriented strategies focus on building actual or perceived resources. These include increasing self-efficacy expectations, optimism (Luthans et al., 2007), and positive affect (Cohn et al., 2009). Masten et al. (2009) define process-oriented strategies as effective adaptive systems and processes that are activated to appropriately deal with potential risk factors. Strategies from this domain often include elements of self-reflection and self-regulation.

The Gratitude Intervention, Random Acts of Kindness, and Three Good Things exercises from the 6-Minute Diary may lead to increases in positive affect (e.g., Martínez-Martí et al., 2010) and optimism (e.g., McCullough et al., 2002; Watkins et al., 2003), potentially involving increases in resilience (Gallagher et al., 2020). Furthermore, the use of the 6-Minute diary could lead to the development of self-efficacy expectations, which in turn potentially could have a positive impact on the development of resilience.

The German version of the Perceived Stress Scale (PSS-10, Schneider et al., 2020) was used to assess perceived stress. The scale captures to which extent individuals perceive situations in their lives as excessively uncontrollable, unpredictable, and stressful relative to their subjective coping abilities. The 10 items (e.g., “In the past month, how often have you felt unable to control the important things in your life?”) are answered on a 5-point rating scale. The scale ranges from 1 = “never” to 5 = “very often.” Here, higher scores indicate higher levels of perceived stress. Examination of internal consistency across the three measurement time points showed Cronbach’s α between 0.89 and 0.91 and McDonald’s ω between 0.92 and 0.93.

Positive and negative affect was assessed using the German version of the Positive and Negative Affect Schedule (PANAS; Krohne et al., 1996). Participants were asked to rate 20 items, in terms of different sensations and feelings, on a 5-point rating scale regarding their intensity over the past 2 weeks. The scale ranges from 1 = “not at all” to 5 = “extremely,” with 10 adjectives each capturing the dimensions of positive affect (e.g., “active”) and negative affect (e.g., “distressed”). Higher scores indicate higher levels of positive and negative affect, respectively. Examination of internal consistency across the three measurement time points showed Cronbach’s α ranging from 0.91 to 0.93 for positive affect and 0.82 to 0.88 for negative affect. McDonald’s ω between 0.93 and 0.95 for positive affect and 0.88 and 0.91 for negative affect.

Schwarzer and Jerusalem (2010) General Self-Efficacy Scale was used to assess self-efficacy. Ten items (e.g., “I face difficulties calmly because I can always trust my abilities.”) are rated on a 6-point rating scale ranging from 1 = “Strongly disagree” to 6 = “Strongly agree.” Here, higher scores indicate higher levels of self-efficacy. Examination of internal consistency across the three measurement time points showed Cronbach’s α between 0.91 and 0.92 and McDonald’s ω between 0.92 and 0.94.

Resilience was assessed using the German version of the Brief Resilience Scale (BRS; Chmitorz et al., 2018). This is based on the resilience definition that resilient individuals have the ability to not succumb to and recover from stress (Smith et al., 2008). Six items (e.g., “I tend to recover quickly after difficult times.”) are answered on a 5-point rating scale, with response options ranging from 1 = “Strongly disagree” to 5 = “Strongly agree.” Here, higher scores indicate higher levels of resilience. Examination of internal consistency across the three measurement time points showed Cronbach’s α between 0.80 and 0.89 and McDonald’s ω between 0.87 and 0.94.

Following Proyer et al. (2015), we asked participants in the intervention group to rate how they liked the intervention using single-item ratings (1 = “not at all” to 7 “very much”) and to provide a subjective assessment of whether they derived personal benefit from the intervention and, if so, how they quantified that benefit (1 = “no, not at all” to 5 = “yes, very much”). Furthermore, we asked about compliance and asked participants to rate how much they adhered to the instructions (0% = “not at all” to 100% = “completely”).

Prior to the main analysis, a MANOVA was conducted to examine whether participants in the intervention group and the control group differed in their baseline scores on perceived stress, resilience, positive and negative affect, self-efficacy, gender, and age. Results showed no difference between groups, Pillai’s trace = 0.018, F(5,151) = 0.567, p = 0.726 (Grissom and Kim, 2012). The Pearson Chi-square test showed no gender differences in the distribution of participants in the conditions [χ²(1, N = 157) = 0.002, p = 0.962, Cramer’s φ = 0.004]. Furthermore, there were no differences in the age structure of the different groups [t(155) = −0.972, p = 0.33]. Means, standard deviations, and Cronbach’s α for both groups at all three measurement time points are presented in Table 1 on the next page. Preliminary analyses and descriptive statistics were performed using IBM SPSS version 25.

We tested the hypotheses using path analyses. For this, we specified a structural model with autoregressive and cross-lagged effects to control for correlations within measurement time points and autoregressive influences (Kearney, 2017). Variables were allowed to correlate within their respective measurement time points. We specified seven theoretically significant cross-lagged effects: negative affect and (1) positive affect, (2) stress, and (3) resilience; (4) stress and self-efficacy; and resilience and (5) positive affect, (6) self-efficacy, and (7) stress. An overview of all the cross-lagged effects can be seen in Figure 2. We used Hu and Bentler’s (1999) standard criteria to evaluate the structural model. The results indicate that the specified model represents the data well [χ²(37) = 18.69, p = 0.995, SRMR = 0.023, RMSEA = 0.000, CFI = 1.00, TLI = 1.031]. The robust maximum likelihood estimator was used as the estimation method for the path analysis to correct for the non-normal distribution of the data. For path analysis, we used the package “lavaan” (Rosseel, 2012) of the statistical software R (version 4.0.3).