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

Understanding social interactions among students comprises a rich area of physics education research. Here we focus on the social interactions in introductory physics laboratories (labs). Most existing research in such contexts focuses on within-group social dynamics, however, we argue that interactions between different lab groups are just as valuable, especially in nontraditional (reformed) labs where students have more control over the experimental designs. Using video recordings of lab sessions and social network analysis methods, we examined whether and for how long groups interact with each other, comparing across three offerings of an introductory mechanics course. We observed significant variability in the interactions across lab sessions and no clear pattern in how strongly lab groups were connected in the networks between the different courses. More prolonged intergroup interactions, however, occurred in three of the four reformed lab sections, as compared to a traditional lab section and a reformed lab section that took place in the evening. We also developed a group-level social role classification scheme based on groups’ interaction patterns, identifying four roles: noninteractors, information seekers, responders, and mutual interactors. We found that groups in the traditional lab section disproportionately acted as noninteractors, indicating that many groups in this lab did not engage in intergroup interactions at all. In contrast, groups in reformed lab sections took on the remaining three roles more frequently. We also found possible relationships between the distributions of the social roles within each type of lab by the groups’ gender compositions. All-male groups took on interactive roles more often than all-female and mixed-gender groups in the reformed lab sections, but not in the traditional lab. Results indicate that the amount of time students spend on intergroup interactions may depend on the lab curriculum itself, the time of day of the section, and/or the student population of the section. Still, instructors can encourage collaboration between lab groups through direct prompts, but such prompts need to be repeated throughout the semester.

Figure 1

Schematic of the classroom layouts for the five lab sections analyzed in this study. Solid black lines inside each layout represent the location of the classroom’s door. Classrooms for sections 1, 2, and 3 may have more than one lab group at adjacent tables. All lab tables (and lab groups) are physically separated in the classroom for sections 4 and 5.

Figure 2

Sample network diagrams for four sessions of lab sections 1 and 4 produced from our video coding. Each node represents a lab group and nodes are positioned according to the actual table layout of the classroom (Fig. 1). Node sizes are proportional to degree and are scaled the same for all diagrams. Edge thickness is proportional to strength, the sum of the time durations of interactions. Edge arrows point from the group that initiated the interaction to the responding group.

Figure 3

(a) Unweighted network density, the proportion of observed edges to possible edges between groups, plotted over time for all coded lab sessions. (b) Normalized total strength, the sum of durations of all observed intergroup interactions scaled by the length of the lab session and number of groups present, over time for all coded lab sessions. Colors indicate the lab curriculum and shapes indicate the lab section.

Figure 4

Transformed scatterplot with a point for each observed lab group based on normalized outstrength and normalized instrength. Colors of each point indicate the social role assigned to the group by our analysis.

Figure 5

Network diagram of session 2 of section 4. Each node represents a lab group and is positioned according to the actual table layout of the classroom (Fig. 1). Node size is proportional to degree. Edge thickness is proportional to strength. Edge arrows point from the group that initiated the interaction to the responding group. Nodes are colored by the social role assigned to them by our analysis.

Figure 6

Stacked bar charts of the proportion of groups of each gender composition and in total that take on each social role within each lab curriculum. The early, traditional lab contained no all-female groups.

Figure 7

Histogram of the normalized instrength data using the fourth root transformation. Though we maintain a peak at zero, the rest of the data exhibit a fairly normal distribution.

Figure 8

Histogram of the normalized outstrength data using the fourth root transformation. Though we maintain a peak at zero, the rest of the data exhibit a fairly normal distribution.

Figure 9

Elbow plot for the $k$-means cluster analysis using the data transformed with the fourth root function. Maximizing the proportion of total sum of squares explained by the between-cluster sum of squares informed our choice to perform cluster analysis with $k=4$.

Figure 10

Cluster plot showing a point for each lab group based on their measures of normalized instrength and normalized outstrength. Point colors indicate the cluster to which the group was assigned using the $k$-means clustering algorithm.

Figure 11

Network diagrams for all coded sessions of section 1.

Figure 12

Network diagrams for all coded sessions of section 2.

Figure 13

Network diagrams for all coded sessions of section 3.

Figure 14

Network diagrams for all coded sessions of section 4.

Figure 15

Network diagrams for all coded sessions of section 5.