This study revealed contextual attributes that promote positive social interdependence during PBL and how they function. Two attributes that affect social interdependence were uncovered: academic inquisition and work efficiency. Then we explained the processes to work the attributes with five steps. Ultimately, these attributes culminated in the interdependent behavior of complementing each other's learning objectives.
PBL is said to foster positive social interdependence [22, 23]. This study revealed the process by which this occurs by analyzing a PBL program in a Japanese context. We begin by discussing whether the results are consistent with SIT as a theoretical framework and its components (outcome, means, boundary) . First, the students’ academic interest in the case attracted their attention and made them seek out problems to solve. Simultaneously, the students consider solving the problems to be a task that was completed in a fixed curriculum where they were expected to finish it properly. This attitude indicates that academic inquisition and desire to improve work efficiency in PBL facilitates positive outcome interdependence because structuring situations that support it results in increased effectiveness and productivity .
The students dealt with these perceptions through two measures. One was to speak up and share their academic inquiries, and the other was to seek each other's contributions to increase efficiency. These led to a mutually complementary behavior of wanting to share their ideas and learning achievements. We considered that the processes resulted in positive means interdependence because the process includes interaction patterns through task, role, and resource . Because PBL was seen as a set task in an official curriculum, the students’ willingness to complete the task may have promoted task interdependence. Then, when each student was expected to contribute to the promotion of task interdependence, the use of role interdependence was required. Some knowledgeable students and tutors were expected to have a role in making progress as well. We can observe these findings within the group discussion phase of PBL (e.g. steps 1–5 in the seven-steps approach). The remaining steps are also related because step 6 is self-study for the complemented learning objectives and, in step 7, students integrate information within the group. Thus, while we have found contextual attributes within the discussion phase of PBL in this study, they presuppose the subsequent steps of self-study and learning integration. The students purposefully acted on the social interdependence described above for the sake of academic inquiry and efficiency. These behaviors are similar to previous research on non-learning environments. Wageman  explains that group achievement increases cooperation while the level of perceived effort affects the quality of group performance in his research at a large corporation.
The remaining component, boundary interdependence was also observed. Students were asked to understand the differences of opinion in their groups and to contribute their diverse perspectives based on those differences. The findings we observed in this study are consistent with previous articles. For example, Torre et al.  claims that entitativity (the perception of a group as a single entity) is important in PBL because it affects the group’s pursuit of common goals and group decisions. In addition, they also advocate that individual responsibility plays another key role in the collaboration . Because the performance of a member affects the outcome of the whole group, each member feels responsible for the performance outcome. There is a concern that “social loafing” can lead to unproductive work in the group . This is unlikely if discussion is well designed to establish individual accountability and engage personal performance with group achievement, including changing the group allocation process  and providing the underlying ideas of PBL . There was no indication that participants were aware of other groups to discuss with during PBL, as the structure of PBL assumes that students learn within their assigned groups. Thus, we cannot argue how other groups affect academic inquiry or efficiency of the work.
Research shows that PBL cultivates social interdependence and offers a partial explanation of group dynamics in general , such as the success of group learning . However, PBL does not only occur in group work; the perceptions and work of each participant affects discussions in the curricula of undergraduate health professions. The students are forced to think about individual achievement and learning outcomes as long as they receive the summative assessment of themselves . Since group functioning and individual contributions are difficult to separate in terms of successful learning , it is necessary to assess not only knowledge but also group dynamics in PBL. The results of this study will contribute to that assessment through the lens of social interdependence.
Our findings also explain why PBL did not function as expected in some contexts like Asia. In the worst situation, the students were confused by the tutor's demand for self-directed learning, and the tutor was frustrated by the students' inability to deepen the discussion. Such a situation was described as a failure by educational researchers . There has also been debate about the reasons for the failure of the PBL-based curriculum. While they have been discussed as independent factors, our findings explain this phenomenon as a failure to provide efficiency in PBL because individual academic inquiry was not cultivated. As some educators pointed out , their PBL practices were not sufficiently linked to the achievement goals in their undergraduate program. Therefore, their PBL practices failed to evoke the academic inquiry that is essential for constructing academic goals within PBL. In addition, the East Asian emphasis on the significance of high-stakes testing in learning made students more aware of operational efficiency in learning rather than academic inquisition . As a result, the students expected that someone who had enough knowledge to learn would take the initiative to guide them through the process. Hence, a side effect of the stronger burden on the tutors also manifested as a relative insufficiency of the tutors’ skills . Therefore, the process of exchanging and sharing ideas through discussion did not feel more efficient than independent study in the theoretical framework of social interdependence and did not create an environment for students to have constructive group discussions. Another argument about Asian students in PBL is that they typically avoid dialogues at the expense of their own interests . Mutual contribution through dialogue will take a lot of time and undermines the efficiency of learning. If the tutor fails to arouse enough interest to merit discussion, the student will try to avoid dialogues and work through the discussion promptly.
Several factors inhibit the discussion of PBL, such as previous educational systems, tutor behavior, and assessment systems . Our findings are consistent with these factors. If the existing educational system is passive in handling tasks, it must prioritize efficiency over academic inquiry. Students’ expectations of tutor behavior would also be heavily weighted toward simply providing the knowledge that is required for learning. The response to high-stakes exams also prioritizes efficiency. Regardless of whether this phenomenon is judged a “failure,” it is an adaptation of PBL to the East Asian context .
Our findings can be used to adjust PBL using SIT as a theoretical framework. It is necessary to strike a balance between academic inquiry and efficiency. As mentioned above, PBL practices in East Asia have overemphasized operational efficiency; therefore, instruction that can guide students to encourage academic inquiry would be useful. In the assessment, not only the acquisition of learning items, but also attitudinal items, such as outcomes and social interdependence in the means of learning, could be assessed. Since skills to promote positive social interdependence can be trained , any feedback provided through the lens of SIT may be useful.
This model could also be applied as an innovative tool for collaborative learning. There is an argument that educational researchers can integrate the forces of PBL and team-based learning (TBL) by combining the benefits of both . One example is the enhancement of boundary interdependence. TBL incorporates a process of comparing the learning outcomes of groups, which is a typical strategy for creating boundary interdependence. However, PBL is not fundamentally designed to compare learning achievement between groups, and we did not find any evidence that other groups influenced social interdependence in PBL. For example, if we could provide an opportunity for students to show their reaction towards the case beyond the group and discuss in a larger group, we could strengthen the processes of social interdependence in our model. Alternatively, future studies might include technology-enhanced learning, as technology will certainly contribute to future education , and online collaborative learning is becoming more popular . However, problem-solving in the online environment is sometimes frustrating for students  since the quality of communication decreases in virtual discussions. There have been several reports on online or blended PBL, some of which succeeded in technically fostering the group process or improving the cooperation during the self-directed learning [39, 40]. We should ensure positive social interdependence as much as possible based on our findings when we conduct further online or blended PBL. For example, using chat and response tools together to encourage participants to participate in discussions will make it easier to share them and make their contributions visible to each other . In addition, using a learning management system to assess understanding instead of relying on tutors  would complement academic inquisition. These specific methods should be explored in future research.
Strengths and limitations
These findings might enable innovations that new intervention procedures can be suggested for tutors. Since tutor training is a crucial component of a successful PBL curriculum , various curricula to improve tutors’ competencies in PBL have been implemented. For example, Azer suggested twelve tips, such as building trust and encouraging the bonding of group members, as well as promoting group dynamics . However, balancing academic inquisition and work efficiency will be required in terms of positive social interdependence, in addition to group cohesiveness. For example, encouraging professional identity formation and self-directed learning attitude  by self-reflection about students' social expectations and personal identity as a future profession , may introduce student more academic inquisition and thus make PBL sessions more beneficial.
On the other hand, there are some limitations. First, as discussed earlier, since the study was conducted in Japan, there could be criticism that Asian faculty have conducted PBL differently under the teacher-centered and examination-based learning culture [8, 32]. The tutor of PBL has understood the notion. He tried not to let the power difference affect the discussions and reflect his facilitation by taking a memo after every PBL session as well as conducting interviews. There is also a refutation that Asian students could adjust to PBL after some experience with the method . If the cultural characteristics of the students continued to affect these findings, we can refer the difference of social interdependence perception into rejection avoidance and harmony-seeking attitudes . According to their study, there is no difference in harmony seeking between Japan and the United States, but Japanese respondents reveal higher rejection avoidance. When the notion is transferred to this model, attitude to pursue work efficiency might be strengthened while sharing inquisition might be decreased.
Second, this study is based on a hybrid PBL curriculum in a single university, and therefore, tends to be influenced by other factors in the curriculum besides PBL itself . Since other active learning opportunities (e.g., TBL and various group work activities) are followed by the PBL in the curriculum, the effects of other opportunities cannot be denied.
Third, the PBL tutor also served as the interview and analyst. It is possible that this may have had an impact on the collection and analysis of data from students. However, he was not involved in the summative assessment and he regularly reflected on the text and analysis with the other authors to reduce the impact as much as possible to ensure reflexivity of the research.
In conclusion, this study revealed that there were two contextual attributes (academic inquisition and work efficiency) for positive social interdependence in PBL based on analysis in an East Asian undergraduate context. In the pursuit of both academic inquiry and operational efficiency, students created a positive social interdependence that called for shared problem-solving and mutual contributions. From these findings, further analysis of the phenomena during discussions, training of tutors, and innovative learning environments are determined to be more effective in collaborative learning practices.