Generative mechanistic explanation building in undergraduate molecular and cellular biology*

ABSTRACT

When conducting scientific research, experts in molecular and cellular biology (MCB) use specific reasoning strategies to construct mechanistic explanations for the underlying causal features of molecular phenomena. We explored how undergraduate students applied this scientific practice in MCB. Drawing from studies of explanation building among scientists, we created and applied a theoretical framework to explore the strategies students use to construct explanations for ‘novel’ biological phenomena. Specifically, we explored how students navigated the multi-level nature of complex biological systems using generative mechanistic reasoning. Interviews were conducted with introductory and upper-division biology students at a large public university in the United States. Results of qualitative coding revealed key features of students’ explanation building. Students used modular thinking to consider the functional subdivisions of the system, which they ‘filled in’ to varying degrees with mechanistic elements. They also hypothesised the involvement of mechanistic entities and instantiated abstract schema to adapt their explanations to unfamiliar biological contexts. Finally, we explored the flexible thinking that students used to hypothesise the impact of mutations on multi-leveled biological systems. Results revealed a number of ways that students drew mechanistic connections between molecules, functional modules (sets of molecules with an emergent function), cells, tissues, organisms and populations.     

Shape-shifting Davydov’s ideas for early number learning in South Africa

In this paper, we share details of a South African early grades’ number intervention informed by aspects of Davydov’s writing on early number teaching and learning. A key part of Davydov’s approach to early number teaching involves starting with attention to relationships between quantities rather than with counting. The Structuring Number Starters (SNS) intervention focused—over a nine-year period—on supporting early grades’ students to move beyond the calculating-by-counting approaches that are prevalent in South Africa. In attending to this focus, the intervention shifted increasingly towards an emphasis on relationships between quantities, though not in the same format or task sequence as advocated by Davydov. The contextual and cultural features that led to our adaptations—or shape-shifting—are highlighted in this paper. We interrogate key aspects of Davydov’s approaches to early number teaching in relation to key features typical of South African classroom mathematics teaching in order to understand the evolution of the SNS initiative. Quasi-longitudinal interview-based assessment data available from a cross-attainment sample of students in 2011, 2014 and 2018 indicate shifts over time from calculating-by-counting to calculating-by-structuring. These outcomes point to successes with moves into increasingly structured ways of working with early number, but suggest also that these successes may be contingent on some fluency with forward and backward number word sequences. The outcomes suggest that it is feasible to explore interventions directing attention to early number structure from the outset in larger scale studies.

     

Within-session changes in responding during delayed matching-to-sample and discrimination procedures

Two experiments examined within-session changes in responding during discrimination procedures. In Experiment 1, rate of responding changed significantly within sessions during symbolic delayed matching-to-sample tasks when the delay between the stimulus and the choice period was short (1–5 sec), but not when it was long (8–12 sec). The percentage of responses that were correct did not change within sessions. In Experiment 2, response rates increased and then decreased within sessions during both S1 and S2 when successive discrimination procedures provided high, but not low, rates of reinforcement. Discrimination ratios sometimes increased within sessions. These results question two potential definitions of attention as explanations for within-session changes in response rates. They are more compatible with explanations based on concepts such as arousal, satiation, habituation, and interfering responses.     

The effects of American Sign Language as an assessment accommodation for students who are deaf or hard of hearing

Students who are deaf or hard of hearing (SDHH) often need accommodations to participate in large-scale standardized assessments. One way to bridge the gap between the language of the test (English) and a student's linguistic background (often including American Sign Language [ASL]) is to present test items in ASL. The specific aim of this project was to measure the effects of an ASL accommodation on standardized test scores for SDHH in reading and mathematics. A total of 64 fifth- to eighth-grade (ages 10-15) SDHH from schools for the deaf in the United States participated in this study. There were no overall differences in the mean percent of items students scored correctly in the standard vs. ASL-accommodated conditions for reading or mathematics. We then conducted hierarchical linear regression analyses to analyze whether measures of exposure to ASL (home and classroom) and student proficiency in the subject area predicted student performance in ASL-accommodated assessments. The models explained up to half of the variance in the scores, with subject area proficiency (mathematics or reading) as the strongest predictor. ASL exposure was not significant with the exception of ASL classroom instruction as a predictor of mathematics scores.     

Gender Norms and Discourses Informing College Men’s Perceptions of Heteronormative Sexual Health Responsibilities and HPV Prevention

Focus group data revealed that despite reporting expectations for high levels of sexual activity, college men primarily identifying as heterosexual were ambivalent about sexual health responsibility and their role in preventing human papillomavirus (HPV). Participants identified shared sexual health responsibility as an ideal but invoked heteronormative gender discourses to rationalize inequality in partnered sexual health. Self-categorization processes based on gender may prevent college males from engaging self- and partnered protective behaviors. Yet, self-categorization processes also enabled college men to envision a future relational identity as husband and father in which they engaged protective sexual health behaviors. Although discourses may signify latent benevolent sexism, they may also make room for behavior change through dissonance or messages encouraging superordinate categorization that urges engaging in preventive sexual health behaviors regardless of gender. Implications for self-categorization processes in HPV prevention are discussed.     

At-Risk High School Students Recovering Course Credits Online: What We Know and Need to Know

The majority of American high school students enrolling in online education are doing so in credit recovery courses. These are online courses specifically for students who previously failed a face-to-face version of the course. Despite the popularity of credit recovery courses, the literature on online learning largely ignores credit recovery courses and students. Assuming credit recovery students are similar to other online learners can be misleading. In this article, the existing literature on credit recovery is reviewed in 3 specific areas: the proliferation of credit recovery courses, the student experience in credit recovery courses, and outcomes and impacts of credit recovery. Suggestions are given for how to advance the credit recovery literature in future research of online learning.     

The effects of expressions of fear induced by background music on reading comprehension

Background

Research has suggested that background music can have a positive or negative effect that can influence the affective state of individuals. Although research has demonstrated that fear negatively influences our cognitive performance, there is a research gap in understanding the combined effects of different background music tempo and fear in influencing reading comprehension performance.

Methods

Data were collected from 70 participants enrolled at a public university in Canada. Participants were required to listen to background music of varying speeds with three conditions (no music, slow music and fast music). We adopted a cross-sectional multi-level modelling approach for the main analyses, and further analyses using t-test and ANOVA.

Results

Results indicated that expression of fear was not a significant predictor of participants' reading comprehension performance (Model 1). However, when music condition was added (Model 2) in addition to expression of fear, a significant relationship between reading comprehension performance and music condition was found, showing better reading comprehension performance in the slow music condition than in the no music condition. Furthermore, there was a significant interaction effect between music condition and expression of fear on reading comprehension performance (Model 3). Importantly, not all individuals were affected by the music to the same extent, with the possibility that baseline level of fear being the key issue in influencing comprehension performance.

Conclusions

Considering both expression of fear and music condition is required to understand the combined effects on cognitive performance. Expression of fear during cognitive tasks such as reading could be an essential signal that interventions should be applied. Such strategies may be especially beneficial for task performers with higher baseline levels of fear and possibly provide us with insights for best practice and research implications in the field of reading comprehension among individuals with special needs.