The mediating role of psychological capital on the relationship between perceived stress and self-directed learning ability in nursing students

Perceived stress encompasses an individual's evaluation of stress levels arising from stimulating events, manifested as feelings of tension or lack of control [10]. A survey involving 1,010 participants revealed that 72% of students experienced high levels of stress, with 73% experiencing anxiety, depression, or other mental health problems [11]. According to the "general stress" theory, stress can contribute to maladaptive behaviors [12]. Students experiencing higher levels of perceived stress often exhibit lower self-control capabilities, more pronounced burnout, and a greater propensity to cope with stress through maladaptive behaviors (e.g., excessive internet or smartphone usage), potentially leading to a decline in their self-directed learning abilities [9, 13, 14]. Despite the established association between stress and self-directed learning among nursing students, the potential mechanism linking perceived stress and self-directed learning remains poorly understood.

Psychological capital is a positive psychological state manifested by individuals in the process of growth and development, including self-efficacy, hope, optimism, and resilience, which play important roles in individual adaptation to the environment and emotion regulation [15]. According to social cognitive theory, self-efficacy is an important factor that influences students' self-directed learning abilities. An individual's self-efficacy determines the motivation level and goals of later learning behaviors [16]. Students with higher self-efficacy are more likely to use self-directed learning strategies than those with lower self-efficacy, often demonstrating higher self-directed learning abilities [17].

Self-efficacy, hope, optimism, and resilience are essential constituents of psychological capital and closely correlated with the capacity for self-directed learning [18‐20]. Individuals can sustain a constructive mind-set and employ proactive coping strategies when faced with adversity, thereby alleviating the detrimental consequences of stress. Stressors, such as academic, employment, further education, and life-related issues, can deplete individuals' limited psychological resources, leading to learning burnout and a decline in self-directed learning ability [9, 13, 14, 21, 22]. Perceived stress is an important predictive factor of psychological capital, which is a protective factor for self-directed learning ability [23, 24].

Based on previous theoretical perspectives and empirical evidence that perceived stress is negatively associated with psychological capital and self-directed learning ability, psychological capital is positively associated with self-directed learning ability. However, the pathways of influence of these three variables remain largely unexplored in the current literature. Nurturing the development of self-directed learning abilities among undergraduate nursing students has consistently been a primary objective of nursing educators. Consequently, the primary focus of this study was on undergraduate nursing students, utilizing perceived stress as an independent variable, psychological capital as the mediating variable, and self-directed learning ability as the dependent variable. This study aimed to investigate the association between perceived stress and self-directed learning ability and to elucidate the mediating role of psychological capital. This study sought to provide nursing educators with a robust theoretical framework that enhances the self-directed learning abilities of undergraduate nursing students. Building on existing relevant research, this study formulates the following hypotheses: 1) Perceived stress exerts a negative predictive effect on self-directed learning ability among undergraduate nursing students, and 2) Psychological capital serves as a mediating factor in the relationship between perceived stress and self-directed learning ability among undergraduate nursing students.

Luthans formulated the notion of psychological capital in the context of positive organizational behavior and positive psychology [15]. Psychological capital is a vital positive personal resource that encompasses self-efficacy, hope, optimism, and resilience [25]. Specifically, individuals with elevated levels of psychological capital possess supplementary resources to manage their work and learning. They hold positive expectations of favorable outcomes, exhibit rapid recovery from setbacks, and display heightened optimism, even under adverse circumstances [15]. Individuals exhibiting elevated levels of psychological capital are inclined to perceive stress as a challenge rather than a threat, and possess enhanced coping abilities and regulatory strategies to manage and contend with stress. Consequently, this positive perceived stress contributes to sustaining a positive psychological state and fostering their motivation to learn, thereby augmenting their capacity for self-directed learning.

A cross-sectional survey was conducted using convenience sampling to select undergraduate nursing students from 10 universities in Xi'an, Shaanxi Province, China, between February and March 2023. The inclusion criteria were as follows: (1) full-time undergraduate nursing students in a four-year program; (2) nursing undergraduate students who voluntarily signed an informed consent form. Students who were not enrolled in school for reasons, such as taking a leave of absence or joining the military, were excluded. The sample size was calculated with the formula N = 4Uα²S²/δ² [26]. S = 0.68 was determined based on the preliminary experimental results. The allowable error δ is set to 0.1, and α is set to 0.05; therefore, N = 4 × 1.96² × 0.68²/0.1²≈710. Considering the 15% invalid questionnaire rate, I have decided to set the minimum sample size as 817. A total of 900 undergraduate nursing students were included in this study—54 male students and 846 female students.

Following unified training, the questionnaire was distributed to eligible undergraduate nursing students using the Questionnaire Star platform. Quality control was as follows: each IP address was restricted to a single submission to prevent duplicate responses; the questionnaire completion process lasted approximately 15–20 min; invalid questionnaires were excluded, including those with missing responses, consistent answers to all items, or response times of less than 3 min. A total of 913 questionnaires were collected, 900 of which were valid after quality control, for a valid response rate of 98.58%.

The present study complied with the Declaration of Helsinki and was approved by the Ethics Committee of Tangdu Hospital (Approval ID: TDLL-202210–17). All participants fully understood the study and voluntarily signed an informed consent form.

Statistical analysis was performed using SPSS 27.0, and PROCESS Macro. The Gaussian distribution of the data was assessed using the Kolmogorov–Smirnov (K-S) single-sample test and a P-P plot. The data were normally distributed. Descriptive statistics, including frequency, percentage, mean, and standard deviation were used to analyze participants' general demographic characteristics and their scores on perceived stress, psychological capital, and self-directed learning abilities. Independent t-tests and a one-way analysis of variance (ANOVA) were used to compare variations in self-directed learning abilities among participants based on their general demographic characteristics. Pearson’s correlation analysis was performed to investigate the associations between the three variables: perceived stress, psychological capital, and self-directed learning abilities. Harman's single-factor test was employed to assess common method bias arising from self-reported data [32]. PROCESS Model 4 was employed to explore the mediating role of psychological capital between perceived stress and self-directed learning abilities among undergraduate nursing students while controlling for all statistically significant covariates identified in the general demographic analysis [33]. This method is based on ordinary least squares regression and bootstrapping. Furthermore, to assess the impact of perceived stress on self-directed learning abilities among undergraduate nursing students, a bias-corrected percentile bootstrap distribution with a 95% confidence interval was calculated based on 5,000 bootstrap samples [33]. Statistical significance was set at a p-value < 0.05.

Data in this study were collected through online questionnaire completion using the “QuestionStar” platform, which has the potential to introduce common method bias. To mitigate this bias, anonymous responses and reverse scoring techniques were implemented during data collection. Furthermore, the Harman single-factor test was administered to all the collected data, and an exploratory factor analysis was conducted on items measuring perceived stress, psychological capital, and self-directed learning abilities. Exploratory factor analysis identified 11 factors with eigenvalues > 1. The first factor accounted for only 26.80% of the total variance, which was significantly below the 40% threshold [32]. This suggests that the study did not exhibit severe common method bias [32].

This study involved 913 respondents, 900 of whom were undergraduate nursing students who completed the survey. This resulted in a high questionnaire completion rate of 98.58%. Within the cohort of 900 undergraduate nursing students, there were 38 male (6.38%) and 558 female students (93.62%). There were 195 (21.67%), 206 (22.89%), 260 (28.89%), and 239 (26.56%) participants in their first, second, third, and fourth years, respectively. The detailed general demographic characteristics are presented in Table 1.

Table 2 displays the scores of the undergraduate nursing students in terms of perceived stress, psychological capital, and self-directed learning ability across all dimensions. The scores for perceived stress, psychological capital, and self-directed learning ability among nursing undergraduate students were 40.07 ± 5.90, 99.89 ± 16.59, and 87.12 ± 9.20, respectively.

The correlation coefficients between the variables in this study are listed in Table 3. The results of the Pearson correlation analysis showed a negative correlation between self-directed learning ability and perceived stress (r = -0.415, p < 0.001), a positive correlation between self-directed learning ability and psychological capital (r = 0.465, p < 0.001), and a negative correlation between perceived stress and psychological capital (r = -0.630, p < 0.001).

Following the standardization of all variables in this study and control of all statistically significant covariates identified in the general demographic analysis, we employed Model 4 from the SPSS macro program developed by Hayes to examine the mediating role of psychological capital in the relationship between perceived stress and self-directed learning ability [33]. The findings of this study indicated that the regression equation was statistically significant (R ² = 0.225, F = 51.810, p < 0.001). Regression analysis showed that perceived stress negatively predicted psychological capital (β = -0.573, SE = 0.027, t = -21.229, p < 0 0.001), negatively predicted self-directed learning ability (β = -0.168, SE = 0.037, t = -4.532, p < 0.001), while psychological capital significantly positively predicted self-directed learning ability (β = 0.291, SE = 0.038, t = 7.750, p < 0.001).

The mediation model was examined using the Hayes’ methodology. Bootstrap with 5,000 iterations was used to calculate the 95% confidence intervals [33]. The results of this analysis are presented in Table 4. The direct impact of perceived stress on self-directed learning ability is estimated to be -0.168, accompanied by a mediation effect ratio of 50.45%. The 95% confidence interval for the mediation effect ranges from -0.242 to -0.096, wherein zero was not encompassed, signifying a statistically significant direct effect. The mediated impact of psychological capital on the association between perceived stress and self-directed learning ability is estimated to be -0.166, accompanied by a mediation effect ratio of 49.55%. The 95% confidence interval for the mediation effect ranges from -0.232 to -0.106, wherein zero was not encompassed, indicating a significant mediating effect of psychological capital. Figure 1 illustrates the specific pathways through which perceived stress influences self-directed learning ability among undergraduate nursing students.

The findings revealed that perceived stress was a risk factor for the self-directed learning ability of undergraduate nursing students. This validates Hypothesis 1 and is consistent with previous research [9, 13, 14]. Stress is widely recognized as pervasive throughout the entire process of undergraduate nursing education [34]. Undergraduate nursing students encounter a multitude of pressures during their academic journey, including academic and social pressure, interpersonal and romantic relationships, the pursuit of further education, employment, and the transition from student to clinical nurse. The amalgamation of these multiple tasks imposes substantial stress on students. Moderate stress can facilitate active learning, consequently bolstering self-directed learning capabilities. Conversely, excessive stress can lead to behaviors that undermine mental and physical well-being, including social anxiety, loneliness, academic burnout, and smartphone addiction, consequently diminishing self-directed learning ability [1, 13, 14, 24].

Moreover, these findings substantiate the general stress theory, which postulates a substantial influence of stress on undergraduate nursing students [12]. Individuals who perceive higher stress levels are more likely to employ maladaptive coping strategies to alleviate stress, hindering the development of self-directed learning abilities. Conversely, individuals with lower stress perception experience less depletion of self-regulatory resources, which promotes the cultivation of self-directed learning abilities [9, 13, 14, 24].

The main results indicated a significant mediating effect of psychological capital between perceived stress and self-directed learning ability, confirming Hypothesis 2. This suggests that undergraduate nursing students with higher levels of perceived stress experience increased depletion of psychological capital, consequently leading to a decline in their self-directed learning ability. Perceived stress negatively predicts psychological capital; individuals with higher stress levels are more likely to deplete their psychological resources, which is consistent with previous research [23]. Psychological capital, which serves as a positive psychological resource for individuals, can effectively mitigate the adverse impact of stress on oneself [35].

Psychological capital can positively predict individuals' self-directed learning ability [23, 24]. Self-efficacy, optimism, hope, and resilience are integral elements of psychological capital that play a vital role in fostering self-directed learning ability [18‐20, 32]. Self-efficacy can stimulate innate motivation and unwavering determination, thereby motivating active involvement in self-directed learning. Hope serves as an inspiration for individuals to pursue goal attainment relentlessly through devoted learning endeavors, thereby augmenting their self-directed learning abilities. Optimism empowers individuals with the capacity to effectively manage and resolve challenges, contributing to surmounting learning obstacles and enhancing self-directed learning ability. Resilience provides valuable assistance for individuals in confronting academic challenges, surmounting obstacles, and ultimately enhancing their self-directed learning abilities.

Furthermore, the findings of this study validate the stress-coping model, indicating that individuals' psychological capital can influence their perception and coping strategies [36]. Undergraduate nursing students with higher levels of psychological capital tend to view stress as a challenge rather than a threat. They frequently exhibit superior coping skills and regulatory strategies that enable them to manage and address stress effectively, leading to enhancements in their self-directed learning abilities. Perceived stress has the potential to affect self-directed learning through the depletion of psychological capital. Consequently, self-directed learning abilities can be enhanced by reducing perceived stress and enhancing psychological capital.

The present study's findings indicate that perceived stress levels among undergraduate nursing students are elevated compared to the results reported by Onieva-Zafra et al. [37] and Xu et al. [38]. One possible explanation for this phenomenon is that undergraduate nursing students, as a distinct group within a university, often have more academic and professional responsibilities than students in other fields, leading to higher levels of stress. Extensive research has indicated that severe stress experienced during medical education can exert myriad detrimental impacts on individuals, encompassing depression, anxiety, insomnia, internet addiction, feelings of isolation, and, in extreme cases, suicidal tendencies [14, 39]. One study revealed that a substantial majority (74.73%) of nursing students advocated the integration of psychological capital education into the medical curriculum [40]. Hence, it is imperative that nursing administrators and educators monitor the mental well-being of nursing students and consistently implement group-based psychological interventions.

The results of this study revealed that the level of psychological capital among undergraduate nursing students was markedly lower than that reported in the study conducted by Wang et al. [22]. Individuals with elevated psychological capital are adept at managing academic pressure by utilizing internal resources, cultivating optimism, and bolstering self-efficacy. These abilities help them cope effectively with stress, overcome obstacles, avoid burnout, and maintain dedication to professional growth. Research conducted by Dello et al. [41] has consistently shown that training interventions focused on psychological capital can lead to significant improvements in individuals' levels of psychological capital, resulting in long-lasting effects. Considering the relatively modest level of psychological capital, substantive opportunities for advancement have persisted. Consequently, fostering and augmenting the psychological capital of undergraduate nursing students has emerged as an exigent imperative.

The findings of this study suggest that the scores of undergraduate nursing students concerning autonomous learning ability were markedly lower than those reported in the study conducted by Tang et al. [42], yet they still surpassed the average level of self-directed learning ability in China [43]. These findings suggest that the self-directed learning ability of this specific group of undergraduate nursing students was moderately positioned, indicating significant potential for enhancement. Within the context of this study, the scores pertaining to self-management and information processing abilities were relatively high in relation to the domain of autonomous learning ability, whereas the score for collaborative learning ability was comparatively low. Supporting research has indicated that innovative teaching approaches such as group presentations and flipped classrooms have the potential to enhance students' ability to work effectively in teams [44]. Thus, it is imperative for nursing educators to integrate conventional and innovative educational approaches to foster intrinsic motivation, consequently bolstering the self-directed learning abilities of undergraduate nursing students.

This study has certain limitations. First, 94% of the participants were female, and 6% were male. Future studies should include a larger proportion of male participants to obtain more comprehensive and representative results. Second, despite efforts to ensure stringent control over the survey process, it is crucial to acknowledge that the self-administered questionnaire format and inherent subjectivity of psychological assessments may create potential biases in self-reporting. Consequently, the conclusions derived from this investigation can only provide a descriptive depiction of the present circumstances, with inherent limitations on their generalizability. Finally, the use of a cross-sectional research design in this study limited the ability to establish causal relationships in the research findings, offering only suggestive evidence. Future research should employ longitudinal designs or experimental approaches to investigate the causal relationship between perceived stress and self-directed learning ability. Previous research has demonstrated that the utilization of Online Photovoice (OPV), Online Interpretative Phenomenological Analysis (OIPA), and Community-Based Participatory Research (CBPR) approaches can assess the cognitive, affective, and behavioral dimensions of individuals [45‐48]. Subsequent studies should employ OPV and CBPR methodologies to investigate the influence of psychological capital on perceived stress and self-directed learning ability among undergraduate nursing students.