Introducing Desirable Difficulty in Engineering Mathematics with Spaced Retrieval Practice

Spaced retrieval practice is an evidence-based, memory-enhancing instructional technique in which students are asked to practice recall multiple times with temporal delays in between [1], [2]. Spacing out practice naturally increases the difficulty of retrieval and reduces immediate performance [3], but it improves memory in the long term [BLIND], [4]. The short-term costs and long-term benefits of spaced retrieval practice can be explained by the concept of desirable difficulty, which proposes that more difficult exercises during the early stages of learning can improve long-term retention [5]. Instructional techniques that improve learning are much needed in introductory engineering courses that establish foundational knowledge and abilities for first-year students. These courses often pose barriers to success in engineering [6]–[9]. Despite the efforts of the mathematics reform movement of 30 years ago to make calculus a pump instead of a filter [10], calculus continues to pose a challenge. To improve performance and retention in engineering mathematics courses, adopting research-based teaching practices such as spaced retrieval practice has the potential to improve learning in barrier courses and increase the number of STEM graduates. Currently in the second year of a 3-year study (NSF Grant Award #BLIND), we are collecting student performance data from a spaced retrieval practice implementation in engineering mathematics, as well as 9 other undergraduate STEM barrier courses. The engineering mathematics course (Calculus I for Engineers) is a prerequisite for many engineering courses at BLIND university, and therefore it is imperative that students retain the course content. In all courses, we identified 24 target learning objectives in the first half of the semester. In 5 bi-weekly quizzes administered throughout the semester, we assigned each learning objective to either a massed (three questions on the same quiz) or spaced (three questions on three consecutive quizzes) condition. A fourth and final question for all objectives will be asked on a quiz at the end of the semester to measure learning. Our research design is within-subjects, which controls for differences in student ability and effort while giving all students experience with both massed and spaced retrieval practice. In addition, assignment of objectives to conditions is counterbalanced, which controls for differences in the difficulty of different objectives. In this ASEE 2021 poster and full-length paper, we explore the difficulty introduced by spaced retrieval practice in engineering mathematics. Our research question is: How much does spaced retrieval practice impact short-term performance in engineering mathematics? We compare student performance on questions that are asked in either a massed or spaced condition. We expect that performance will be lower on spaced questions than massed questions. Although this analysis will not reveal whether we have induced desirable difficulty, since we are not assessing long-term learning at this time, it will indicate whether we have imposed additional difficulty with the manipulation of spacing. These intermediate results are important for our understanding of the mechanism by which spaced retrieval practice may enhance learning.