Abstract:

Phylogenetic trees are an important visual tool for understanding evolutionary relationships, but their graphical logic often places significant challenges on students. Especially in heterogeneous classes, this raises questions about how instructional support can be designed to be both adaptable and effective. Incremental scaffolds are a promising approach to support learning processes because they offer graduated assistance tailored to learners’ current understanding. Given the heterogeneous state of research regarding the effectiveness of scaffolding for cognitive and motivational outcomes, this experimental intervention study investigated how different instructional approaches with optional support impact students’ learning performance, self-efficacy beliefs regarding phylogenetic tree reading skills, and intrinsic motivation during the intervention. Specifically, optional support was applied through three instructional methods: comprehensive incremental scaffolds, incremental prompts, and incremental worked-out examples. Besides the effects on learning-related outcomes, the study examined whether students who used the optional support differed from non-users in their prerequisites and outcomes, and which factors students considered important in their decision to use or not use support. Using a randomized pre-test-post-test design, data were gathered from 108 upper secondary school students (grades 11 and 12). The pre-test assessed prior knowledge of phylogenetic trees, self-efficacy beliefs regarding phylogenetic tree reading and biology-related skills, along with intrinsic motivation in biology class. During the intervention, students were randomly assigned to one of three treatments offering different types of optional support. The post-test assessed learning performance, self-efficacy beliefs regarding phylogenetic tree reading skills, and intrinsic motivation throughout the intervention. The comparison of the three treatments revealed no significant differences in either cognitive or motivational outcomes. However, exploratory analyses revealed consistent differences in support use: optional support was primarily used by students with lower prior knowledge, lower self-efficacy, and lower intrinsic motivation. Furthermore, students who used support scored lower on post-tests in learning performance and in one dimension of intrinsic motivation, namely interest/enjoyment, than students who did not use support. The results indicate that optional scaffolds are primarily applied by learners who seem to need the most support, demonstrating adaptive self-selection in help-seeking behaviour. At the same time, simply offering optional support does not appear to be enough to address differences in learners’ prerequisites and outcomes. This study thereby adds to current discussions on adaptive support, learner heterogeneity, and the potential and limitations of optional scaffolding in classroom teaching.

Keywords:

Biology education, scaffolding, learning performance, self-efficacy, intrinsic motivation.