1177-threshold-concepts-and-transformational-learning

LAND ET ALEun-Jung Park and Greg Light (Chapter 16) sought to identify a threshold conceptin studies at the atomic and molecular levels in the relatively new field ofnanoscience. Their study (after Davies, 2006) adopted both top-down (expertfocused)and bottom-up (student-focused) methods. These methods included ‘theconstruction of concept maps and an interview with the expert (professor), and theconstruction of pre- and post- course concept maps and the completion of a linkedopen-ended survey by the students’. Interestingly both methods tended to convergeon one particular potential threshold concept, surface area-to-volume ratio, asa candidate for nanoscience, at least within this taught programme. Of thisthreshold concept the expert professor commented:Well, surface-to-volume ratio is the threshold concept, because you can’t getdown here (the nano level) without accepting the fact that really tiny particleshave large surface-to-volume ratio… So take a gram of something and keepchopping it up until you get down to nano-particles. And what you see is thesurface area just goes through the roof. So this is enabling... because, withoutthat, you can’t do this. So this would be a threshold concept.The professor also identified eleven key, or important, concepts within this field.The survey of forty-two student pre- and post-course concept maps revealed thirtyeightfurther concepts, in addition to the professor’s original eleven. The authorsemployed a phenomenographic approach to analyse the experiential component ofthese maps to identify variation in the ways students experienced the troublesomenessof the concept. This revealed ‘a hierarchical continuum of patterns ofunderstanding, each more complex and inclusive of the preceding patterns’ whichproduced an outcome space comprising the following five patterns of student understanding:1. Isolated, 2. Unconnected, 3. Detached, 4. Limited, and 5. Integrated.The key aspect of variation characterising the most complex pattern (‘Integrated’),and the pattern most closely reflecting the expert’s pattern, was the recognition of thecentral role of surface area-to-volume ratio in the integration of the key nano domainconcepts. Both expert and student responses reported this as an integrative concept,whilst two thirds of the students selecting this threshold concept also experienced achange of understanding during the course towards a more sophisticated pattern. Inconsequence the authors conclude that their study presents ‘preliminary evidence thata meaningful understanding of surface area-to-volume ratio critically contributes tostudents’ ability to integrate other key concepts in the nano-domain’.Interestingly, however, the concept surface area-to-volume ratio, thoughselected as a threshold, was not regarded as a particularly troublesome or difficultconcept to understand. The authors suggest this might be owing to the fact that‘troublesomeness does not necessarily reside directly with the threshold conceptbut rather in the integration of the domain cluster of concepts within the student’sunderstanding’.They also report that the representation of student understanding gained fromconcept maps, though useful, is not a sufficiently rich source of data in itself foranalysis and interpretation of student understanding, and their ongoing study willemploy subsequent use of interview data.xxvi