Should students change their answers on multiple choice questions?

Multiple choice exams are ubiquitous, but advice on test-taking strategies varies and is not always well informed by research. This study evaluated the question of whether students benefit or are harmed when they change their initial answers on multiple choice questions in the context of physiology and biology courses. Previously marked examinations were reviewed for eraser marks that indicated answer changes, and the impact of these changes on exam grades was tabulated. In addition, faculty and students were surveyed for their opinions about changing answers. A plurality of faculty (36%) reported a belief that answer changes usually harm student grades, whereas a slim majority of students (51%) believed that answer changing helped their scores (χ2 = 60.52, P < 0.0001). Empirically, across two exams, students changed their answer from an incorrect answer to a correct one 2.8 times (SD 2.2) compared with 1.0 time (SD 1.4) changing in the negative direction. Therefore, on average, students benefited (V = 123.5, P < 0.0001) from answer changing. Furthermore, comparing across two exams in the same course, some students were consistently more likely to change their answers than others (adjusted R2 = 0.23, P < 0.0001), but the impact of changing answers on the first exam provided no prediction of how much a student would benefit from answer changing on the second exam (adjusted R2 = -0.004, P = 0.42). These data support the argument that students should be advised to review and revise responses to exam questions before submitting them.

Teaching animal behavior online: A primer for the pandemic and beyond.

Behavior courses face numerous challenges when moving to an online environment, as has been made necessary by the COVID-19 pandemic. These challenges occur largely because behavior courses, like most organismal biology courses, often stress experiential learning through laboratories that involve live animals, as well as a lecture component that emphasizes formative assessment, discussion, and critical thinking. Although online behavior courses may be remote, they can still be interactive and social, and designed with inclusive pedagogy. Here, we discuss some of the key decisions that instructors should consider, provide recommendations, and point out new opportunities for student learning that stem directly from the move to online instruction. Specific topics include challenges related to generating an inclusive and engaging online learning environment, synchronous versus asynchronous formats, assignments that enhance student learning, testing format and execution, grade schemes, design of laboratory experiences including opportunities for community science, design of synthetic student projects, and workload balance for students and instructors. We designed this primer both for animal behavior instructors who need to quickly transition to online teaching in the midst of a pandemic, and for those facing such transitions in upcoming terms. Much of the manuscript's content should also be of general interest and value to instructors from all areas of organismal biology who are attempting to quickly transition to online teaching.

Variation in compound eye structure: effects of diet and family.

Studies of compound eyes have revealed that variation in eye structure can substantially affect visual performance. Here, we investigate the degree to which a stressful rearing environment, which decreases body size, affects the eye phenotype. Full siblings of the Orange Sulphur butterfly, Colias eurytheme, were collected from known parents and split within families among two diet treatments that varied in quality. In both sexes, individuals reared on the high-quality diet had larger eye height and anterior facet diameter, and therefore, by inference, superior vision. However, relative to their reduced body size, individuals reared on low-quality diet had proportionally larger eyes and facets than individuals reared on high-quality diet. We interpret this finding as evidence that butterflies encountering nutritional stress increased proportional investment in eye development to reduce loss of visual performance. We also found significant broad-sense genetic variation underlying eye structure in both males and females, and report novel heritability estimates for eye height and facet diameter. Surprisingly, there was greater genetic variation in eye height among males than among females, despite apparently stronger directional selection on male vision. We discuss the implications of these data for our understanding of eye development and evolution.

The eyes of a patrolling butterfly: visual field and eye structure in the Orange Sulphur, Colias eurytheme (Lepidoptera, Pieridae).

Sensory information plays a critical role in determining an animal's behavior on both proximate and evolutionary timescales. Butterflies, like many other insects, use vision extensively over their lifetimes, and yet relatively little work has been published to date on their visual capabilities. We describe the visual system of a pierid butterfly, Colias eurytheme, with the ultimate goal of better understanding its role in shaping the behavior of this animal. We made several measurements: visual field dimensions, eye surface area, interommatidial angle (Deltaphi), facet diameter (D), and eye parameter (p). C. eurytheme had a large visual field and considerable regional variation in visual acuity, as inferred by Deltaphi and D. When compared to females, males had larger eye surface areas, smaller Deltaphi, and larger D in all regions except ventrally. Both sexes had proportionally large eye surface areas compared to other butterflies. Minimum p in males was small, indicating that some regions of their eyes may operate close to the diffraction limit. Finally, we found that both eye surface area and D scaled positively, but with negative allometry to body size. We discuss the relevance of these visual characteristics to the biology and behavior of C. eurytheme.