Student Discussion

How to promote intergroup student interaction in an introductory lab

Title: Examining the effects of lab instruction and gender composition on intergroup interaction networks in introductory physics labs

Authors: Meagan Sundstrom, David G. Wu, Cole Walsh, Ashley B. Heim, and N. G. Holmes

First author’s institution: Laboratory of Atomic and Solid State Physics, Cornell University

Journal: Physical Review Physics Education Research 18, 010102 (2022)

Student interactions with peers have been shown to enhance students’ academic achievements, self-efficacy, persistence, and lower their physics anxiety . While existing research focused mostly on within-group interactions, this study dived into interactions between different groups in introductory mechanics labs. The authors argue that intergroup interactions are as valuable to students. Exchange with another group can bounce ideas, identify mistakes, and fulfill a lack of equipment. And because students learn through interaction with others, alternative perspectives can help students better understand the lab activity.

Something I noticed as a college lab instructor is that students can get lost and distracted easily if nobody in the group knows how to tackle the problem they encounter. Sharing what did and didn’t work with another group can generate new ideas and get the group project going. Help from other groups is especially important when the lab instructor or TAs are not immediately available.

In this study, the authors were interested in investigating how structural characteristics of intergroup interactions compared and evolved over a semester. They were also interested in figuring out what social roles the groups in introductory physics labs take on and how the distributions of these roles differ across groups.


This study applied social networking analysis (SNA) to video data of five lab sections across three offerings of an introductory mechanics lab course. All groups in all the five sections were video recorded. The authors identified which groups were interacting, which group initiated the interaction, and the length of the interaction.

Table 1: Summary of the five lab sections analyzed in the study. (Table I in paper.)

In the five labs the authors studied, there were three different curricula: traditional lab providing students with detailed instructions to perform a particular experiment to reach a predefined outcome (section 1); early, reformed lab offering a model and prompting students to design, implement, and refine the experiment (section 2 and 3); recent, reformed lab following the same reformed lab curriculum with a better TA training and general refinement based on observations of early, reformed labs (section 4 and 5). All reformed labs were 2 hours long on average while the traditional lab was shorter.

The design of reformed labs encouraged intergroup interaction because students had more freedom on how they would carry out the experiments and had longer lab time for a longer discussion.


A. Intergroup networks (how intergroup interactions compared and evolved over a semester)

Figure 1: Sample network diagrams. Session 1 and 8 were the first and last lab sessions, respectively. Each node (blue dot in the figure) represents a lab group. Each edge (line connecting two nodes) represents an interaction. This figure shows that the reformed lab (section 4) has more intergroup interactions (fewer edges) compared to the traditional lab (section 1). This figure visualizes how the authors model the lab interactions. But to interpret the result more easily and reach more useful conclusions, we need the following figure: figure 2. (FIG. 2 in paper.)

Figure 2: Unweighted network density (a) and normalized total strength (b) plotted over time for all lab sessions. The unweighted network density is the fraction of possible intergroup interactions observed, without considering the length of each interaction or number of separate interactions (weight of each edge). Normalized total strength is the average fraction of the total lab time each group spent interacting with other groups. (FIG. 3 in paper.)

Surprisingly, there is no common trend over time for all lab sections (Figure 2 a and b). The variation of the trend of each lab suggests that the proportion of groups that interact with other groups does not depend on the lab activities, course or lab layout, or TAs. When the duration or number of separate interactions are not considered, a reformed lab and a traditional lab can have similar numbers of intergroup interactions. However, there were still some differences. Reformed lab networks generally had higher normalized total strength (Figure 2b). That is, groups in reformed labs had more and longer intergroup interactions compared to those in the traditional lab. Based on the fact that section 1 and 5 had lower normalized total strength, the normalized total strength seems to be dependent on the lab curriculum (traditional or reformed) and the time of day.

The authors suggested two possible differences between section 4 and 5 that could explain the different numbers of the interactions: the time of day of the lab section and student population of the section. Section 4 had more students (19 students), was mostly men, and took place in the afternoon. On the other hand, section 5 had fewer students (11 students), was mostly women, and happened in the evening. The authors suspect that fewer intergroup interactions in the evening lab section might be not only due to the time of day, but also the student population (for instance student athletes or students with part time jobs). But their findings should only be taken preliminary because there are only one traditional lab section and one evening lab section in this study.

B. Group-level social roles

The authors identified 4 categories of social roles regarding intergroup interactions. First there were “noninteractors”, which were groups that did not interact with other groups at all. Then there were “information seekers”, which only engaged in intergroup interactions they started, and “responders”, which only engaged in intergroup interactions other groups initiated. Finally, mutual interactors were groups engaging in both intergroup interactions started by their own groups and by other groups.

Figure 3: Proportion of groups of each gender group that take on each social role. (FIG. 6. in paper.)

The authors pointed out that there was a much larger portion of groups in the traditional lab that acted as noninteractors (48%), in contrast to 38% in early reformed labs and 24% in recent reformed labs (Figure 3). Because such difference is not shown in Figure 2a, the authors suggested that only a few groups in the traditional lab engaged in intergroup interactions and contributed to the unweighted density. That is, fewer groups in the traditional lab interacted with other groups compared to in the reformed labs.

Among all-male groups, groups were more interactive in the recent, reformed labs (only 5% noninteractors) than in either the traditional (more than 50% noninteractors) or early, reformed lab (more than 30% noninteractors). There were too few all-female groups in this study to make any claims about them. But notably, none of them acted as information seekers in early, reformed labs while some took on the role in recent, reformed labs. Among mixed-gender groups, more groups acted as mutual interactors in reformed labs (20~25%) than in traditional lab (8%). The increase in mutual interactors was countered by a decrease in information seekers (17% in reformed labs and 30% in the traditional lab).

Comparing groups in the recent, reformed labs, there were much more mutual interactors among all-male groups (47%) than among either all-female (25%) or mixed-gender groups (23%).

The authors also noticed that there were fewer groups acting as noninteractors in the recent, reformed labs (24%) than in the early, reformed labs (38%). The authors suggested two possible causes: (1) Evidence-based modifications made to the reformed labs may have led to more intergroup interactions and (2) Student population differences may have led to the social role difference. Compared to students in early, reformed lab sections, students in recent, reformed lab sections were more diverse in major disciplines and demographic variables.

Summarizing the above findings, it seems that the recent, reformed labs offer more opportunities for lab groups to take on one of the three interactive social roles (information seekers, responders, or mutual interactors), no matter what the group gender composition is.


The authors identified four social roles each group can take on and concluded that lab instruction has the potential to impact the extent to which student interaction with other groups and affect social role distributions. For instance, more prolonged intergroup interactions take place in most of the nontraditional (reformed) labs than in the traditional lab. And more groups acted as noninteractors in the traditional lab.

So what can lab instructors do to encourage intergroup interactions? The authors suggest that instructors can prompt students to interact with other groups directly and repeatedly throughout the term. Personally I think the reason that instructors should prompt students repeatedly in different lab sessions is that students do not get familiar with each other enough and feel awkward every time to initial the conversation. Intergroup interactions can also be boosted by incorporating more open-ended lab tasks and questions instead of single-right-answer or single-procedure tasks.  In this study, the reformed labs allow students to design their own experiments based on some guidance of necessary theoretical background. Unlike a reformed lab, students in a traditional lab would be less likely to discuss with other groups because they are given detailed guidance to perform a specific experiment and have little need or motivation to have intergroup interactions.

Figures used under CC BY 4.0.

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