Covariational reasoning and item context affect language in undergraduate mass balance written explanations.

Mass balance (MB) reasoning offers a rich topic for examination of students' scientific thinking and skills, as it requires students to account for multiple inputs and outputs within a system and apply covariational reasoning. Using previously validated constructed response prompts for MB, we examined 1,920 student-constructed responses (CRs) aligned to an emerging learning progression to determine how student language changes from low (1) to high (4) covariational reasoning levels. As students' abilities and thinking change with Context, we used the same general prompt in six physiological contexts. We asked how Level and Context affect student language and what language is conserved across Contexts at higher reasoning Levels. Using diversity methods, we found student language becomes more similar as covariational reasoning level increases. Using text analysis, we found context-dependent words at each Level; however, the type of context words changed. Specifically, at Level 1, students used context words that are tangential to MB reasoning, while Level 4 responses used words that specify inputs and outputs for the given Item Context. Further, at Level 4, students shared 30% of language across the six contexts and leveraged context-independent words including rate, equal, and some form of slower/lower/smaller. Together, these data demonstrate that Context affects undergraduate MB language at all covariational reasoning levels, but that the language becomes more specific and similar as Level increases. These findings encourage instructors to foster context-independent, comparative, and summative language during instruction to functionally build MB and covariational reasoning skills across contexts.NEW & NOTEWORTHY This article builds on the work of Scott et al. (Scott EE, Cerchiara J, McFarland JL, Wenderoth MP, Doherty JH. J Res Sci Teach 1: 37, 2023) and Shiroda et al. (Shiroda M, Fleming MP, Haudek KC. Front Educ 8: 989836, 2023) to quantitatively examine student language in written explanations of mass balance across six contexts using constructed response assessments. These results present an evaluation of student mass balance language and provide researchers and practitioners with tools to assist students in constructing scientific mass balance reasoning explanations.

What a Difference in Pressure Makes! A Framework Describing Undergraduate Students' Reasoning about Bulk Flow Down Pressure Gradients.

Pressure gradients serve as the key driving force for the bulk flow of fluids in biology (e.g., blood, air, phloem sap). However, students often struggle to understand the mechanism that causes these fluids to flow. To investigate student reasoning about bulk flow, we collected students' written responses to assessment items and interviewed students about their bulk flow ideas. From these data, we constructed a bulk flow pressure gradient reasoning framework that describes the different patterns in reasoning that students express about what causes fluids to flow and ordered those patterns into sequential levels from more informal ways of reasoning to more scientific, mechanistic ways of reasoning. We obtained validity evidence for this bulk flow pressure gradient reasoning framework by collecting and analyzing written responses from a national sample of undergraduate biology and allied health majors from 11 courses at five institutions. Instructors can use the bulk flow pressure gradient reasoning framework and assessment items to inform their instruction of this topic and formatively assess their students' progress toward more scientific, mechanistic ways of reasoning about this important physiological concept.

Undergraduate students' neurophysiological reasoning: what we learn from the attractive distractors students select.

The basis for mastering neurophysiology is understanding ion movement across cell membranes. The Electrochemical Gradients Assessment Device (EGAD) is a 17-item test assessing students' understanding of fundamental concepts of neurophysiology, e.g., electrochemical gradients and resistance, synaptic transmission, and stimulus strength. We collected responses to the EGAD from 534 students from seven institutions nationwide, before and after instruction. We determined the relative difficulty of neurophysiology topics and noted that students did better on "what" questions compared to "how" questions, particularly those integrating concentration gradient and electric forces to predict ion movement. We also found that, even after instruction, students selected one incorrect answer, at a rate greater than random chance for nine questions. We termed these incorrect answers attractive distractors. Most attractive distractors contained terms associated with concentration gradients, equilibrium, or anthropomorphic and teleological reasoning, and incorrect answers containing multiple terms were more attractive. We used χ2 analysis and alluvial diagrams to investigate how individual students moved or did not move between answer choices on the pre- and posttest. Interestingly, students selecting the attractive distractor on the pretest were just as likely as other incorrect students to move to the correct answer on the posttest. In contrast, of students incorrect on both the pre- and posttest, students who selected the attractive distractor on the pretest were more likely to stick with this answer on the posttest than students choosing other incorrect answers. Combining the EGAD results with alluvial diagrams can inform neurophysiology instruction to address points of student confusion.NEW & NOTEWORTHY Investigating students' alternative reasoning in neurophysiology, this research is the first to investigate how analyzing the most common incorrect answer can shed light on the concepts students struggle with when reasoning about neurophysiological problems, especially those dealing with both chemical and electrical driving forces to predict ion movement across cell membranes.

Oaks to arteries: the Physiology Core Concept of flow down gradients supports transfer of student reasoning.

The Physiology Core Concept of flow down gradients is a major concept in physiology, as pressure gradients are the key driving force for the bulk flow of fluids in biology. However, students struggle to understand that this principle is foundational to the mechanisms governing bulk flow across diverse physiological systems (e.g., blood flow, phloem sap flow). Our objective was to investigate whether bulk flow items that differ in scenario context (i.e., taxa, amount of scientific terminology, living or nonliving system) or in which aspect of the pressure gradient is kept constant (i.e., starting pressure or pressure gradient) influence undergraduate students' reasoning. Item scenario context did not impact the type of reasoning students used. However, students were more likely to use the Physiology Core Concept of "flow down [pressure] gradients" when the pressure gradient was kept constant and less likely to use this concept when the starting pressure was kept constant. We also investigated whether item scenario context or which aspect of the pressure gradient is kept constant impacted how consistent students were in the type of reasoning they used across two bulk flow items on the same homework. Most students were consistent across item scenario contexts (76%) and aspects of the pressure gradient kept constant (70%). Students who reasoned using "flow down gradients" on the first item were the most consistent (86, 89%), whereas students using "pressures indicate (but don't cause) flow" were the least consistent (43, 34%). Students who are less consistent know that pressure is somehow involved or indicates fluid flow but do not have a firm grasp of the concept of a pressure gradient as the driving force for fluid flow. These findings are the first empirical evidence to support the claim that using Physiology Core Concept reasoning supports transfer of knowledge across different physiological systems.NEW & NOTEWORTHY These findings are the first empirical evidence to support the claim that using Physiology Core Concept reasoning supports transfer of knowledge across different physiological systems.

Daytime light exposure is a strong predictor of seasonal variation in sleep and circadian timing of university students.

In the absence of electric light, sleep for humans typically starts soon after dusk and at higher latitudes daily sleep timing changes seasonally as photoperiod changes. However, access to electric light shields humans from natural photoperiod changes, and whether seasonal changes in sleep occur despite this isolation from the natural light-dark cycle remains a matter of controversy. We measured sleep timing in over 500 university students living in the city of Seattle, WA (47.6°N) throughout the four seasons; we show that even when students are following a school schedule, sleep timing is delayed during the fall and winter. For instance, during the winter school days, students fell asleep 35 min later and woke up 27 min later (under daylight-savings time) than students during the summer school days, a change that is an hour larger relative to solar midnight. Furthermore, chronotype defined by mid-sleep on free days corrected for oversleep (MSFc), an indirect estimate of circadian phase, was more than 30 min later in the winter compared with the summer. Analysis of the effect of light exposure showed that the number of hours of light exposure to at least 50 lux during the daytime was a stronger predictor of MSFc than the exposure time to this illuminance after dusk. Specifically, MSFc was advanced by 30 min for each additional hour of light exposure during daytime and delayed by only 15 min for each additional hour of postdusk exposure to light. Additionally, the time of the day of exposure to high light intensities was more predictive of MSFc when daytime exposure was considered than when exposure for the full 24-h day was considered. Our results show that although sleep time is highly synchronized to social time, a delayed timing of sleep is evident during the winter months. They also suggest that daily exposure to daylight is key to prevent this delayed phase of the circadian clock and thus circadian disruption that is typically exacerbated in high-latitude winters.

Evidence-based teaching practices correlate with increased exam performance in biology.

Evidence-based teaching practices are associated with improved student academic performance. However, these practices encompass a wide range of activities and determining which type, intensity or duration of activity is effective at improving student exam performance has been elusive. To address this shortcoming, we used a previously validated classroom observation tool, Practical Observation Rubric to Assess Active Learning (PORTAAL) to measure the presence, intensity, and duration of evidence-based teaching practices in a retrospective study of upper and lower division biology courses. We determined the cognitive challenge of exams by categorizing all exam questions obtained from the courses using Bloom's Taxonomy of Cognitive Domains. We used structural equation modeling to correlate the PORTAAL practices with exam performance while controlling for cognitive challenge of exams, students' GPA at start of the term, and students' demographic factors. Small group activities, randomly calling on students or groups to answer questions, explaining alternative answers, and total time students were thinking, working with others or answering questions had positive correlations with exam performance. On exams at higher Bloom's levels, students explaining the reasoning underlying their answers, students working alone, and receiving positive feedback from the instructor also correlated with increased exam performance. Our study is the first to demonstrate a correlation between the intensity or duration of evidence-based PORTAAL practices and student exam performance while controlling for Bloom's level of exams, as well as looking more specifically at which practices correlate with performance on exams at low and high Bloom's levels. This level of detail will provide valuable insights for faculty as they prioritize changes to their teaching. As we found that multiple PORTAAL practices had a positive association with exam performance, it may be encouraging for instructors to realize that there are many ways to benefit students' learning by incorporating these evidence-based teaching practices.

Design-Based Research: A Methodology to Extend and Enrich Biology Education Research.

Recent calls in biology education research (BER) have recommended that researchers leverage learning theories and methodologies from other disciplines to investigate the mechanisms by which students to develop sophisticated ideas. We suggest design-based research from the learning sciences is a compelling methodology for achieving this aim. Design-based research investigates the "learning ecologies" that move student thinking toward mastery. These "learning ecologies" are grounded in theories of learning, produce measurable changes in student learning, generate design principles that guide the development of instructional tools, and are enacted using extended, iterative teaching experiments. In this essay, we introduce readers to the key elements of design-based research, using our own research into student learning in undergraduate physiology as an example of design-based research in BER. Then, we discuss how design-based research can extend work already done in BER and foster interdisciplinary collaborations among cognitive and learning scientists, biology education researchers, and instructors. We also explore some of the challenges associated with this methodological approach.

Does the Format of Preclass Reading Quizzes Matter? An Evaluation of Traditional and Gamified, Adaptive Preclass Reading Quizzes.

Preclass reading quizzes (RQs) have been shown to enhance student performance. Many instructors implementing evidence-based teaching assign preclass RQs to ensure their students are prepared to engage in class activities. Textbook companies now offer a gamified, adaptive-learning RQ format. In these RQs, students answer point-valued questions until they reach a threshold. If students answer incorrectly, the question decreases in point value on the next attempt. These RQs also give students who answer questions incorrectly more questions on that topic and direct students to sections of a textbook they need to review. We assessed the impact of gamified, adaptive preclass RQs compared with more traditional preclass RQs on in-class RQs and course exam performance as well as students' perceptions of RQs. Students in the gamified, adaptive treatment performed equally compared with students in the traditional, static treatment on in-class RQs and course exams. While students in the gamified, adaptive treatment did have a more positive perception of preclass RQs, this factor explained less than 3% of the variation in RQ perception. Our findings suggest that instructors should verify that gamified, adaptive technologies impact student learning in their course before integrating them into their course and asking students to pay for them.

Learning Progressions: An Empirically Grounded, Learner-Centered Framework to Guide Biology Instruction.

Vision and Change challenged biology instructors to develop evidence-based instructional approaches that were grounded in the core concepts and competencies of biology. This call for reform provides an opportunity for new educational tools to be incorporated into biology education. In this essay, we advocate for learning progressions as one such educational tool. First, we address what learning progressions are and how they leverage research from the cognitive and learning sciences to inform instructional practices. Next, we use a published learning progression about carbon cycling to illustrate how learning progressions describe the maturation of student thinking about a key topic. Then, we discuss how learning progressions can inform undergraduate biology instruction, citing three particular learning progressions that could guide instruction about a number of key topics taught in introductory biology courses. Finally, we describe some challenges associated with learning progressions in undergraduate biology and some recommendations for how to address these challenges.

Impact of automated response systems on in-class cell phone use.

Cell phones have long been known as a potential distraction from attention intensive activities such as studying and driving. Many, however, are developing the cell phone as a powerful tool to augment some of these same activities. Audience response systems (ARSs) are a type of teaching tool that allows educators to poll audience members in real time. Increasingly, cell phones are being integrated into ARSs to make them more versatile and affordable. As cell phones and other personal electronic devices (tablets, laptops) are becoming more common classroom learning tools, we sought to explore how student cell phone use is impacted by this change. Additionally, we studied how a student's seat location and how the time during a term impacts students' cell phone use. To measure student cell phone use in lecture, we observed introductory biology classes at the University of Washington and recorded when students' cell phones were visible. We found that students sitting in the back of the room showed an increased likelihood of having a cell phone out. However contrary to our expectations, students using personal device (cell phone) based polling technology were no more likely to be using cell phones during lecture than their peers using traditional ARSs. Our results suggest that the downsides to using cell phones as teaching tools may be limited. © 2019 The International Union of Biochemistry and Molecular Biology, 47(5):538-546, 2019.

A new assessment to monitor student performance in introductory neurophysiology: Electrochemical Gradients Assessment Device.

The basis for understanding neurophysiology is understanding ion movement across cell membranes. Students in introductory courses recognize ion concentration gradients as a driving force for ion movement but struggle to simultaneously account for electrical charge gradients. We developed a 17-multiple-choice item assessment of students' understanding of electrochemical gradients and resistance in neurophysiology, the Electrochemical Gradients Assessment Device (EGAD). We investigated the internal evidence validity of the assessment by analyzing item characteristic curves of score probability and student ability for each question, and a Wright map of student scores and ability. We used linear mixed-effect regression to test student performance and ability. Our assessment discriminated students with average ability (weighted likelihood estimate: -2 to 1.5 Θ); however, it was not as effective at discriminating students at the highest ability (weighted likelihood estimate: >2 Θ). We determined the assessment could capture changes in both assessment scores (model r2 = 0.51, P < 0.001, n = 444) and ability estimates (model r2 = 0.47, P < 0.001, n = 444) after a simulation-based laboratory and course instruction for 222 students. Differential item function analysis determined that each item on the assessment performed equitably for all students, regardless of gender, race/ethnicity, or economic status. Overall, we found that men scored higher (r2 = 0.51, P = 0.014, n = 444) and had higher ability scores (P = 0.003) on the EGAD assessment. Caucasian students of both genders were positively correlated with score (r2 = 0.51, P < 0.001, n = 444) and ability (r2 = 0.47, P < 0.001, n = 444). Based on the evidence gathered through our analyses, the scores obtained from the EGAD can distinguish between levels of content knowledge on neurophysiology principles for students in introductory physiology courses.

Peer vs. Self-Grading of Practice Exams: Which Is Better?

Practice exams are a type of deliberate practice that have been shown to improve student course performance. Deliberate practice differs from other types of practice, because it is targeted, mentally challenging, can be repeated, and requires feedback. Providing frequent instructor feedback to students, particularly in large classes, can be prohibitive. A possible solution is to have students grade practice exams using an instructor-generated rubric, receiving points only for completion. Students can either grade their own or a peer's work. We investigated whether peer or self-grading had a differential impact on completion of practice exam assignments, performance on practice exams or course exams, or student grading accuracy. We also investigated whether student characteristics mattered. We found that 90% of students took all practice exams or only missed one and that there was no difference on practice or course exam performance between the peer and self-graders. However, in the peer-grading treatment, students with lower incoming grade point averages and students identified as economically or educationally disadvantaged were less accurate and more lenient graders than other students. As there is no clear benefit of peer grading over self-grading, we suggest that either format can solve the challenge instructors face in giving frequent personalized feedback to many students.

Connections between student explanations and arguments from evidence about plant growth.

We investigate how students connect explanations and arguments from evidence about plant growth and metabolism-two key practices described by the Next Generation Science Standards. This study reports analyses of interviews with 22 middle and high school students postinstruction, focusing on how their sense-making strategies led them to interpret-or misinterpret-scientific explanations and arguments from evidence. The principles of conservation of matter and energy can provide a framework for making sense of phenomena, but our results show that some students reasoned about plant growth as an action enabled by water, air, sunlight, and soil rather than a process of matter and energy transformation. These students reinterpreted the hypotheses and results of standard investigations of plant growth, such as van Helmont's experiment, to match their own understanding of how plants grow. Only the more advanced students consistently interpreted mass changes in plants or soil as evidence of movement of matter. We also observed that a higher degree of scaffolding during some of the interview questions allowed mid-level students to improve their responses. We describe our progress and challenges developing teaching materials with scaffolding to improve students' understanding of plant growth and metabolism.

Plant-soil feedback: testing the generality with the same grasses in serpentine and prairie soils.

Plants can alter soil properties in ways that feed back to affect plant performance. The extent that plant-soil feedback affects co-occurring plant species differentially will determine its impact on plant community structure. Whether feedback operates consistently across similar plant communities is little studied. Here, the same grasses from two eastern U.S. serpentine grasslands and two midwestern tallgrass prairie remnants were examined for plant-soil feedback in parallel greenhouse experiments. Native soils were homogenized and cultured (trained) for a year with each of the four grasses. Feedback was evaluated by examining biomass variation in a second generation of (tester) plants grown in the trained soils. Biomass was lower in soils trained by conspecifics compared to soils trained by heterospecifics in seven of 15 possible cases; biomass was greater in conspecific soils in one other. Sorghastrum nutans exhibited lower biomass in conspecific soils for all four grasslands, so feedback may be characteristic of this species. Three cases from the Hayden prairie site were explained by trainer species having similar effects across all tester species so the relative performance of the different species was little affected; plants were generally larger in soils trained by Andropogon gerardii and smaller in soils trained by S. nutans. Differences among sites in the incidence of feedback were independent of serpentine or prairie soils. To explore the causes of the feedback, several soil factors were measured as a function of trainer species: nutrients and pH, arbuscular mycorrhizal (AM) spore communities, root colonization by AM fungi and putative pathogens, and functional diversity in bacterial communities as indicated by carbon substrate utilization. Only variation in nutrients was consistent with any patterns of feedback, and this could explain the greater biomass in soils trained by A. gerardii at Hayden. Feedback at Nottingham (one of the serpentine sites) differed, most notably for A. gerardii, from that of similar past studies that used different experimental protocols. To understand the consequences of feedback for plant community structure, it is important to consider how multiple species respond to the same plant-induced soil variation as well as differences in the feedback detected between greenhouse and field settings.

Testing nickel tolerance of Sorghastrum nutans and its associated soil microbial community from serpentine and prairie soils.

Ecotypes of Sorghastrum nutans from a naturally metalliferous serpentine grassland and the tallgrass prairie were assessed for Ni tolerance and their utility in remediation of Ni-polluted soils. Plants were inoculated with serpentine arbuscular mycorrhizal (AM) root inoculum or whole soil microbial communities, originating from either prairie or serpentine, to test their effects on plant performance in the presence of Ni. Serpentine plants had marginally higher Ni tolerance as indicated by higher survival. Ni reduced plant biomass and AM root colonization for both ecotypes. The serpentine AM fungi and whole microbial community treatments decreased plant biomass relative to uninoculated plants, while the prairie microbial community had no effect. Differences in how the soil communities affect plant performance were not reflected in patterns of root colonization by AM fungi. Thus, serpentine plants may be suited for reclamation of Ni-polluted soils, but AM fungi that occur on serpentine do not improve Ni tolerance.