Theme: 7BB Approaches to teaching and learning
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Unexpected Difficulties In Cell Biology Revealed By Drawings Of First Year Medical Students
Authors: Rui M. Goncalves (1)
Nuno S. Osorio (1)
Celine Pinheiro (2)
Eduardo A. Garcia (2)
Manuel J. Costa (1)
Institutions: 1- School of Health Sciences. University of Minho, Braga, Portugal.
2- Barretos School of Health Sciences, Dr. Paulo Prata , Barretos, Brazil.
 
Background

A challenge inherent to learning cell biology is the interpretation of representational illustrations and understanding the spatial organization of cells.

The process of drawing cells, i.e. producing  “a learner-generated external visual representation depicting any type of content, whether structure, relationship, or process, created in static two dimensions in any medium” can facilitate learning. By drawing, students create external representations which illustrate their mental images (internal representations) of the invisible cellular entities, processes and concepts.

It is important that students develop awareness of their own internal representations, as students use them as foundations for new knowledge and, as such, potential misconceptions based on incorrect representations may be perpetuated and contribute to learning difficulties and misunderstandings. 

Summary of Work

Our goals were:
i. to identify first year medical student difficulties related to the structure of a cell;
ii. to evaluate whether those difficulties would differ between two countries;
iii. to characterize the origin of such difficulties.

What was done in class:
A surprise in class assignment asked students to draw: 1. an eukaryotic cell representation; 2. an epithelial cell under the microscope.

Participants and methods:
Participants were 386 first year medical students from one school in Portugal and another in Brazil. Drawings were anonymized and mistakes were coded by 2 pairs of experts using a consensus criteria list as a reference. Conducted interviews were semi-structured and with 17 purposefully selected participants.

Summary of Results

There were four main groups of mistakes: 1. scale; 2. general structure; 3. intracellular structure; and 4. odd representations.
Portugal and Brazil displayed identical mistakes, except for scale issues, which were more common in students from Brazil. The most likely mistake origins identified in interviews were textbooks schemes and the lack of hands-on laboratory experience.

 

Conclusion

The cell drawings created by first year medical students contained mistakes which pointed to inaccurate knowledge about the cell structure and to difficulties in understanding the limits of microscopic observations. The student interviews revealed that, in some cases, the mistakes reflected misconceptions which had endured over pre-university education. Identical mistake categories were prevalent across 3 cohorts in 2 countries, which suggest that such mistakes and misconceptions could be cross-cultural.

Take-home Messages

Drawing may be a useful teaching strategy to reveal otherwise unnoticed misconceptions.

References
  • Braund, M., & Reissb, M. (2006). Towards a More Authentic Science Curriculum: The contribution of out-of-school learning. International Journal of Science Education, 28(12), 1373–1388.
  • Dikmenli, M. (2010). Misconceptions of cell division held by student teachers in biology: A drawing analysis. 
  • Kose S. (2008). Diagnosing student misconceptions: using drawings as a research method. World Appl ASci J, (3), 283–293.
  • Quillin, K., & Thomas, S. (2015). Drawing-to-Learn: A Framework for Using Drawings to Promote Model-Based Reasoning in Biology. CBE Life Sciences Education, 14(1). doi:10.1187/cbe.14-08-0128
  • Klymkowsky, M. W., Underwood, S. M., & Garvin-Doxas, R. K. (2010). Biological Concepts Instrument (BCI): A diagnostic tool for revealing student thinking. http://arxiv.org/abs/1012.4501. Other.
  • Schönborn, K. J., Anderson, T. R., & Grayson, D. J. (2002). Student difficulties with the interpretation of a textbook diagram of immunoglobulin G (IgG). Biochemistry and Molecular Biology Education, 30(2), 93–97.
  • Francek, M. (2013). A Compilation and Review of over 500 Geoscience Misconceptions. International Journal of Science Education, 35(1), 31–64. doi:10.1080/09500693.2012.736644
  • Miller, B. W., & Brewer, W. F. (2010). Misconceptions of Astronomical Distances. International Journal of Science Education, 32(12), 1549–1560.
Background
Summary of Work

Participants
The population consisted of first year undergraduate medical students of the School of Health Sciences of University of Minho (ECS-UM), Braga, Portugal and the Barretos School of Health Sciences, Dr. Paulo Prata - FACISB, Barretos, São Paulo, Brazil. A total of 420 students representing 3 cohorts (2012, 2013 and 2014) were invited to participate and 386 students (91.9 % participation) created drawings [(85% from Portugal and 15% from Brazil] 31 % of drawings were made in 2012, 43% in 2013 and 26% in 2014.
Collection of drawings
Students were asked to create two drawings: i) a schematic representation of an eukaryotic cell including all organelles (implemented with the intention to understand how students recall the types, number and position of organelles within a cell); and ii) a representational drawing of a fresh preparation of a buccal epithelium swab when visualized under the optical microscope (implemented to address the notion of scale at the microscopic level and also of shape, position and size of the cells and organelles and whether they would be visible in a fresh preparation visualized under optical microscopy).
The students were in the initial 2-3 weeks of their undergraduate medical degree and had not taken any class on microscopic observation of cells at the university. The assignment was presented without prior announcement at the beginning of the first practical class on microscopy. The purpose of the assignment was explained and students were ensured that their drawings would not be marked for academic purposes. It was also clarified that participation was voluntary. The faculty leading the class distributed print copies of the assignment form and asked students to identify their drawings, so they could be interviewed later. Students had 20 minutes to complete their drawings individually.
Analysis of drawings
Phase I (definition of criteria). In both countries, drawings were collected, anonymized and coded. NSO, EG and MJC analyzed the drawings to identify mistakes that would result from potential misconceptions.
Phase I (analysis). The drawings were divided into two groups and attributed to a pair of faculty members for evaluation (CP/EG or NSO/RG). Each evaluator individually scored each drawing according to the defined categories of mistakes. Disagreements in the categorization were settled through consensus between all authors and there was no need to add further categories. The evaluations were compiled into a unique dataset by RG.
Clarification interviews
Semi-structured interviews were conducted to probe the origins of mistakes in representations and misconceptions. Free response-type questions were used so students could respond with what came to mind. Invitations were made to students in the 2014 cohort that had recently made the drawing assignment and that produced the scrub drawings with at least one mistake. All interviewed students signed informed consent forms. The interview started by asking students to observe their drawings. Then, students were asked to explain in their own words what was represented in the drawings. They were subsequently questioned about size, relative scale, position and identity of all the drawn structures and if they believed anything was missing. Students were then asked if they though their drawings were “correct” and what was their opinion regarding the causes of the incorrect aspects. Individual interviews were conducted by RG with 17 students. All interviews were transcribed and submitted to content analysis to differentiate mistakes from misconceptions and to identify the most frequent reported origins for the misconceptions.

Summary of Results

Figure 1 - Typical drawings with mistakes.

A correct representation of an oral swab under the microscope is shown in Figure 1A. There were essentially 6 types of mistakes in the drawings of the epithelial scrub slide under the microscope (several representations exhibited multiple mistakes): mistake 1, representations of a single rounded cell (Figure 1B); mistake 2, representations of “tissue-like” structures (Figure 1C); mistake 3, representations of organelles other than the nucleus (Figure 1D); mistake 4, representations of doubled layered cell membranes (Figure 1E); mistake 5, representation of nucleus misplaced in a polar position (Figure 1F); mistake 6, odd representations (Figure 1G). The frequency of the mistakes 1-6 was very similar (mistake 1 (29.5%), 2 (26.5%), 3 (22%), 4 (27%), 5 (21%) and 6 (25.6%). Among the odd representations (mistake 6) drawings of sharped edged epithelial buccal cells were the most frequent representing 48.4% of all the odd structures (12.4% of all drawings).

Figure 2 - Variations in mistakes across cohorts

The results from the comparative analysis of student mistakes revealed that the difficulties of the two populations fitted in the same categories. The frequencies however were significantly different (p<0.05) in both countries with an increase of 26%, 15% and 26% in Brazil when compared to Portugal in unicellular representations (53% in Brazil vs. 27% in Portugal), double layers membrane representations (21% in Brazil vs. 6% in Portugal) and organelles other than nucleus (46% in Brazil vs. 20% in Portugal). Misplaced nuclei (20%) and microorganisms (3%) were equally common in illustrations from both countries.

Analysis of student interviews
To help clarifying the meaning and origins of the identified drawing mistakes 17 students were interviewed. These interviews suggested that scaling mistakes resulted mostly from illiteracy and technical aspects of the drawing. Students referred they were unaware about cell or organelle sizes and that they had guessed dimensions in order to draw. They understood that the nucleus was the largest structure but were uninformed about the relative sizes of other structures, even though they showed awareness that the organelles were of different relative sizes. Some students attributed the scale difficulties to insufficient high school microscopy classes. Others indicated that they attempted to reproduce drawings from textbooks.
Most students who represented tissue like structures and single cells were expecting to find a histological piece. Students who illustrated rectangular shaped cells (similar to vegetable tissues) attributed representations to high school laboratory  observation of onion cells. The presence of single cells was explained as a personal choice, some students stated that they were expecting to see more but preferred to present only one to show greater structural detail. Some students chose to only draw bacteria and food remains, these believed that that an oral scrub could not effectively collect oral cells. In what concerns intracellular organization, it was apparent that students who produced misplaced nuclei were unsure of its position.

 

Conclusion
Take-home Messages
References
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