The analysis of human walking gait is a complex skill for physical therapy students to learn. As a result, students are at risk for a cognitive overload when confronted with these materials. Cognitive load consists of both intrinsic and extraneous loads as well as the germane processes that are required by the learners to process the information in working memory. As working memory is limited in its capacity to process new information, it is necessary to manage the cognitive load experienced by the learners. Intrinsic cognitive load is related to the complexity of the materials that must be learned and cannot be altered by instructional design without sacrificing initial understanding. An isolated elements instructional format purports to reduce the intrinsic CL experienced by learners by isolating the content into the individual elements prior to introducing any complex relationships that may exist between the elements. The purpose of this study was to examine the cognitive load and learning outcome effects of an isolated elements instructional format versus an interacting elements format when teaching observational gait analysis to physical therapy students.
A total of 72 students enrolled in a Doctor of Physical Therapy program participated in this study. Mixed factorial designs assessed both between-group and within-group outcomes. The independent variables were the group assignments (isolated or interacting) and time. The dependent variables were cognitive load and learning outcomes. Cognitive load was measured with 7-point Likert-type scales for both mental effort and task difficulty at five separate time points. Learning outcomes were assessed through performance scores and confidence ratings on a posttest and a 1-week follow-up test. Animated videos were used as the medium for instructional delivery. In the isolated elements group, the learners received the content in several separate videos that isolated each of the sub-phases of gait prior to viewing a summary video that included all of the interacting gait cycle components. Learners in the interacting elements group received the content in one video that included the full gait cycle followed by the same summary video.
Students in the isolated elements groups reported lower mental effort ratings immediately after viewing the isolated elements videos than did the interacting group after viewing the single video tutorial. However, there was no differences in either mental effort or task difficulty ratings at the other time points during the lesson or during the assessments. Performance scores and confidence ratings did not differ between the two groups. Within-group analyses found that there were significant changes over time in both groups for mental effort, performance scores, and confidence ratings. A statistically significant change was noted over time for task difficulty in the interacting elements group. The reduction in mental effort ratings immediately following the tutorial content for the isolated elements group lends support the theory that isolating the individual elements prior to teaching the complex interactions can reduce cognitive load for learners. However, this reduction in cognitive load did not translate into improved test scores or confidence compared to the interacting elements group. Future research is needed to identify instructional methods that can further reduce the cognitive load and increase the learning outcomes of students learning observational gait analysis. In addition, alternative objective methods of assessing cognitive load should be explored.