Persistent Miscalibration for Low and High Achievers Despite Practice Test Feedback in an Introductory Biology Course

Students\u27 ability to accurately judge their knowledge is crucial for effective learning. However, students\u27 perception of their current knowledge is often misaligned with their actual performance. The relationship between learners\u27 perception of their performance and their actual performance on a task is defined as calibration. Previous studies have shown significant student miscalibration in an introductory biology course: students\u27 predicted exam scores were, on average, significantly higher than their actual scores. The goal of this study was to determine whether completion of a practice test before exams would result in better performance and calibration. The hypothesis was that students who completed a practice test would perform better and be better predictors of their performance on exams than students who did not engage in practice testing. As predicted, students who voluntarily completed a practice test, on average, performed better and were more calibrated than students who did not. Importantly, however, many of the lowest-performing students continued to significantly overestimate their knowledge, predicting higher scores on the exam than they actually earned, despite feedback from practice tests. In contrast, practice testing was associated with underconfidence in high-performing students. These findings indicate that practice tests may enhance calibration for many students. However, additional interventions may be required for the lowest-performing students to become better predictors of their performance

Opportunities for Self-Evaluation Increase Student Calibration in an Introductory Biology Course

Accurate self-evaluation is critical for learning. Calibration describes the relationship between learners’ perception of their performance and their actual performance on a task. Here, we describe two studies aimed at assessing and improving student calibration in a first-semester introductory biology course at a 4-year public institution. Study 1 investigated students’ (n = 310) calibration (the difference between estimated and actual exam performance) across one semester. Students were significantly miscalibrated for the first exam: their predicted scores were, on average, significantly higher than their actual scores. The lowest-performing students had the most inaccurate estimates. Calibration improved with each exam. By the final exam, students underestimated their scores. We initiated a second study in the following semester to examine whether explicitly teaching students about self-evaluation strategies would improve their calibration and performance. Instruction in the experimental section (n = 290) focused on students’ tendency to overestimate their abilities and provided retrieval-practice opportunities. Students in the experimental section showed better calibration and performance on the first exam compared with students in a control section taught by a different instructor during the same semester (n = 251). These findings suggest that simple instructional strategies can increase students’ metacognitive awareness and improve their performance

Phylogeny and biogeography of the Enhydris clade (Serpentes: Homalopsidae)

Previous molecular phylogenetic hypotheses for the Homalopsidae, the Oriental-Australian Rear-fanged Water Snakes indicate that Enhydris, the most speciose genus in the Homalopsidae (22 of 37 species), is polyphyletic and may consist of five separate lineages. We expand on earlier phylogenetic hypotheses using three mitochondrial fragments and one nuclear gene, previously shown to be rapidly evolving in snakes, to determine relationships among six closely related species: Enhydris enhydris, E. subtaeniata, E. chinensis, E. innominata, E. jagorii, and E. longicauda. Four of these species (E. subtaeniata, E. innominata, E. jagorii, and E. longicauda) are restricted to river basins in Indochina, while E. chinensis is found in southern China and E. enhydris is widely distributed from India across Southeast Asia. Our phylogenetic analyses indicate that these species are monophyletic and we recognize this clade as the Enhydris clade sensu stricto for nomenclatural reasons. Our analysis shows that E. chinensis is sister-species to a well-supported clade comprising the remaining species of the Enhydris clade (mean p distance between E. chinensis and other in-group taxa was 13.1%, range: 12.7-13.4%). Enhydris innominata, E. longicauda and E. jagorii also formed a strongly supported clade with very low interspecific p distances (mean 0.28%, range: 0–0.46%). We were unable to resolve relationships between E. enhydris and E. subtaeniata (mean divergence of 9.4%, range: 9.2-9.7%), and between these two species and E. innominata, E. longicauda and E. jagorii. We summarize classical morphological (scalation and coloration) characteristics of these species in the context of the molecular phylogeny. The Enhydris clade comprises a substantial portion of the vertebrate biomass of Southeast Asia and we discuss aspects of its biogeography, morphology and systematics