The participants in this study were first-year vocational high school students from four parallel classes (Electromechanical Class 1, Electromechanical Class 2, Numerical Control Class 1, and Electromechanical 3 + 4 Class) of the 2023 cohort at a vocational secondary school in Shandong Province, China, totaling 241 students initially recruited. Given that all participants were from this locality, where primary and junior high schools exclusively utilize traditional teaching methods centered on lecture-based instruction, it can be reasonably assumed that none had prior exposure to the PERMA model or other related positive psychology models or theories. Furthermore, participation in this project was entirely voluntary, with no attendance requirements during the instructional sessions. Ultimately, 239 students from the four parallel classes voluntarily participated in the study. However, during the research process, 11 students failed to complete all assessments, and an additional 21 students submitted blank or invalid questionnaires for at least one assessment, ultimately yielding a final valid sample of 207 students.

This study utilized the Inventory of Positive Mental Characters among Chinese Middle School Students developed by Meng et al. (2016). The scale comprises six subscales: Cognition (KMO = 0.738, α = 0.66), Emotion (KMO = 0.738, α = 0.76), Willpower (KMO = 0.731, α = 0.77), Self-discipline (KMO = 0.679, α = 0.64), Altruism (KMO = 0.763, α = 0.80), and Transcendence (KMO = 0.871, α = 0.86). It contains 63 items scored on a 5-point Likert scale ranging from “Not at all like me” to “Very much like me.” The scale measures positive psychological qualities across six dimensions, aligning well with the psychological characteristics of Chinese middle school students, and each subscale demonstrates sufficient reliability and validity.

Additionally, the researchers developed a questionnaire on the current state of teaching in the Mechanical Drawing course for vocational high schools. This was designed to facilitate a more detailed understanding and comparison of the learning conditions of participants in Groups A and B throughout the study. In 2021, the Shanghai Municipal Education Commission issued the Implementation Methods for Comprehensive Quality Evaluation of Vocational High School Students in Shanghai, which established a system comprising five modules and 22 indicators to evaluate the comprehensive quality of vocational students. This system reflects the characteristics of vocational education with high scientific and objective standards (Shanghai Municipal Education Commission, 2021). Given that Mechanical Drawing is only one specialized course within the training system for mechanical majors in vocational high schools, this study excluded three modules from the original evaluation system that were unrelated to this course. The remaining modules, “Skills and Academic literacy” and “Labor” and “Professional literacy,” were retained. Based on the core content of these two modules, four evaluation dimensions were extracted: “Learning interest,” “Learning attitude,” “Course comprehension,” and “Professional literacy.” Additionally, given the generally low learning motivation among vocation high school students and the significant impact of positive psychology on individual motivational states (Li, 2019; Pajares, 2001), this study incorporated the dimension of “Learning motivation” into the questionnaire. This was intended to examine the extent to which the PERMA-Based PBL Teaching Model enhances participants’ learning motivation. To gauge participants’ attitudes toward the innovative teaching model, the questionnaire added an “Attitude toward the new teaching model” dimension in the pre-test and an “Attitude toward the current teaching method” dimension in the mid-and post-tests. The final questionnaire comprised six dimensions: “Learning interest,” “Learning attitude,” “Course comprehension,” “Learning motivation,” “Attitude toward the new teaching model/current teaching method,” and “Professional literacy.” It included 17 items scored on a 5-point Likert scale ranging from “Strongly agree” to “Strongly disagree.” It is important to note that the questionnaire has two versions: a pre-test version and a combined mid-test and post-test version. The pre-test version included “Attitude toward the new teaching model” as the fifth dimension, while the combined mid-test and post-test version replaced it with “Attitude toward the current teaching method.” The other dimensions remained consistent across versions. Both versions demonstrated sufficient reliability (Pre-test: KMO = 0.862, α = 0.89; Mid-and Post-test: KMO = 0.877, α = 0.85).

For data analysis, SPSS Statistics 27.0 was used to analyze the data collected from both the scale and the questionnaire.

To strictly adhere to the principle of educational equity, the four parallel classes were divided into two groups, A and B, based on their initial test scores on the Inventory of Positive Mental Characters among Chinese Middle School Students (Meng et al., 2016), ensuring balanced levels of performance across the groups. Group A comprised Electromechanical Class 1 and Electromechanical Class 2, with a total of 104 students, while Group B included Numerical Control Class 1 and the Electromechanical 3 + 4 Class, with a total of 103 students.

As shown in Figure 2, the research employed a crossover experimental design divided into two phases. The study commenced on February 26, 2024, and concluded on June 28, 2024. The first phase spanned from February 27 to April 25, and the second phase from April 27 to June 27. The pre-test, mid-test, and post-test were administered on February 26, April 26, and June 28, respectively. During the research process, Groups A and B commenced the first phase the day after completing the pre-test. In this first phase, Group A followed the traditional teaching model, while Group B implemented the PERMA-based PBL teaching model. The mid-test was conducted the day after the conclusion of the first phase. Following the mid-test, Groups A and B commenced the second phase the next day. During this second phase, Group A transitioned to the new teaching model, while Group B switched to the traditional teaching model. The post-test was administered the day after the conclusion of the second phase.

Table 1 presents the changes in positive psychological qualities of participants in Groups A and B throughout the experimental process. In the first phase of the study, the traditional teaching model used by Group A had a moderately significant effect (p < 0.05) on improving participants’ positive psychological qualities only in the “Cognition” dimension, with no significant effects observed in the other dimensions. In contrast, the PERMA-based PBL teaching model used by Group B highly significant improved (p < 0.001) all six dimensions of positive psychological qualities measured by the scale.

During the second phase, Group A, which transitioned to the new teaching model, exhibited highly significant improvements across all six dimensions of positive psychological qualities. Meanwhile, Group B, which switched to the traditional teaching model, showed moderately significant improvements in the “Cognition,” “Emotion” and “Self-discipline” dimensions, and significant improvements (p < 0.01) in the “Willpower” and “Transcendence” dimensions.

Table 2 presents the intergroup differences in the positive psychological qualities of participants in Groups A and B during the experiment. Since the four parallel classes were grouped using a balanced approach based on their initial scores, and neither group had prior exposure to positive psychology theories, the pre-test scores of Groups A and B were nearly identical. At the end of the first phase, the positive psychological qualities of Group B participants, who received the new teaching model, were highly significantly higher across all six dimensions compared to those of Group A participants, who followed the traditional teaching model. By the end of the second phase, the positive psychological qualities of Groups A and B converged, with no significant differences observed between the two groups.

Table 3 presents the changes in the learning states of participants in Groups A and B throughout the experiment. In the first phase of the study, the traditional teaching model employed in Group A moderately significantly enhanced participants’ “Professional literacy,” while improvements in other dimensions were not statistically significant. In contrast, the novel teaching model applied in Group B produced highly significant improvements in participants’ “Learning interest” and “Learning motivation,” significant improvements in their “Course comprehension,” and moderately significant enhancements in their “Learning attitude.” However, it did not lead to significant improvements in participants’ “Professional literacy.”

In the second phase, participants in Group A exhibited highly significant improvements across all six dimensions of learning states measured by the questionnaire. For Group B, compared to their mid-test levels, participants showed highly significant improvement in “Professional literacy,” significant improvement in “Learning motivation,” moderately significant improvement in “Course comprehension,” but a highly significant decline in their “Attitude toward the current teaching method.” Additionally, in the pre-test, the scores for “Attitude toward the new teaching model” were 3.31 and 3.38 for Groups A and B, respectively, exceeding the theoretical midpoint by 10.3 and 12.7%.

Table 4 presents the intergroup differences in the learning states of participants in Groups A and B during the experiment. As shown, there were no significant differences between Groups A and B in their learning states during the pre-test. After the first phase of teaching, Group B participants scored significantly higher than Group A in three dimensions: “Learning interest,” “Learning motivation,” and “Attitude toward the current teaching method,” with highly significant differences. In the “Learning attitude” dimension, Group B also scored moderately significantly higher than Group A. After the second phase, Group A participants exhibited a highly significant advantage over Group B in their “Attitude toward the current teaching method.” Beyond this, no significant differences were observed between the two groups.

It is evident that the PERMA-based PBL teaching model outperformed the traditional teaching model in enhancing the positive psychological qualities of vocational high school students, aligning with findings from studies across other educational levels (Kovich et al., 2023; Kern et al., 2015). Instruction guided by the PERMA model provides students with increased positive emotional experiences and overall well-being, thereby fostering individual and societal flourishing (Dorri and Aghaei, 2024).

However, as shown in Table 1, the efficacy of the traditional teaching model in improving participants’ positive psychological qualities differed between Groups A and B. In Group A, the traditional teaching model implemented during the first phase only yielded moderately significant improvements in participants’ “Cognitive” levels. Conversely, in Group B, the traditional teaching model used during the second phase resulted in statistically significant enhancements across five dimensions: “Cognition,” “Emotion,” “Willpower,” “Self-discipline,” and “Transcendence.” This discrepancy may be attributed to the new teaching model applied to Group B during the first phase, which established more positive teacher-student relationships prior to their exposure to traditional instruction. Consequently, even without incorporating positive psychology theories in subsequent teaching, researchers still exerted a beneficial influence on this group’s positive psychological qualities. In classroom settings, negative teacher-student relationships undermine students’ autonomy and subjective well-being, ultimately impairing their academic performance and mental health (Zhou et al., 2023). Conversely, positive teacher-student relationships significantly boost students’ well-being, learning motivation, and academic achievement—a finding consistent with this study’s experimental results (Robinson, 2022).

Collectively, the PERMA-based PBL teaching model not only provides vocational students with more positive emotional experiences but also facilitates stronger teacher-student relationships, thus comprehensively enhancing their positive psychological qualities.

Based on the data presented in Tables 3, 4, it is evident that vocational high school students demonstrate a stronger preference for the novel teaching model. Furthermore, the novel teaching model exhibits significantly greater effectiveness than the traditional teaching model in enhancing students’ learning interest and learning attitudes, thereby reconfirming the role of positive psychology theory in improving students’ learning states (Al-Mansoori and Dana, 2017).

However, as illustrated in Table 4, the advantages of the novel teaching model over the traditional model in improving students’ “Course comprehension” and “Professional literacy” are less pronounced. Regarding “Course comprehension,” the novel teaching model highly significantly enhanced this dimension among participants in Group A and significantly enhanced it in Group B. In contrast, the traditional teaching model had a moderately significant effect on improving course comprehension in Group B but showed no significant effect in Group A. This indicates that the novel teaching model outperforms the traditional model in enhancing participants’ comprehension of the course. One reason for the non-significant results in the independent-samples t-test of the mid-test mean scores for the “Course comprehension” dimension between Groups A and B is that the pre-test mean score for this dimension in Group B was lower than that in Group A.

Concerning “Professional literacy,” Table 3 reveals minimal improvement in this dimension for both groups during the first phase of the study, whereas highly significant enhancement was observed in the second phase. This pattern may be attributed to the logical structure of the Mechanical Drawing course content. In mainland China, this course is typically taught in a sequence of theory followed by practice (Zhu and Xu, 2020). Consequently, the teaching content in the second phase incorporated substantially more practice-oriented tasks closely aligned with real workplace environments compared to the first phase. Since practice serves as an effective means to enhance engineering students’ innovation capabilities and professional literacy (Chen et al., 2021), this discrepancy may have led to an uneven rate of improvement in students’ professional literacy levels between the two phases. Additionally, participants in this study were simultaneously enrolled in other specialized courses during the research period, which may have also influenced their professional literacy levels.

As technology continues to advance, society demands increasingly higher levels of professional literacy from vocational high school students. How to comprehensively enhance students’ professional literacy during the teaching process and strengthen their competitiveness in the job market remains a significant educational challenge (Huang et al., 2011).

The participants in this study were exclusively first-year mechanical students from a vocational high school in Shandong Province, with no inclusion of students from other disciplines or regions. This limits the generalizability of the findings to a broader student population. Furthermore, in mainland China, male students significantly outnumber females in vocational high school mechanical programs. As a result, this study did not specifically explore gender as a factor.

This study confirmed the effectiveness of the PERMA-based PBL teaching model. Future research should aim to extend the application of this teaching model to other disciplines, educational stages, and countries or regions while exploring demographic variables in greater detail to evaluate and refine the model further.

Additionally, leveraging positive psychology theories or models as guiding frameworks to reform traditional teaching practices represents a promising direction for positive education. Future studies could adaptively select various positive psychology theories and compatible teaching models based on course characteristics to achieve optimal teaching outcomes.

Finally, as an important framework within positive psychology, the PERMA model is undoubtedly effective in improving individual health and well-being. However, its five core elements are not absolutely comprehensive and may benefit from refinement. Future researchers could consider modifying the dimensions of the PERMA model to develop a more holistic approach to enhancing participants’ positive psychological qualities.