New Perspectives in Science Education

There are few instruments for the assessment of students’ conceptions about natural selection and biological adaptation so far (e.g. [1]). Existing instruments differ considerably in task format, features, contexts, etc. Studies have revealed that assessment item features like context associate with knowledge elicitation. Different tasks with varying contexts testing the same scientific concept may cue different student conceptions. Little is known for whatever reason students activate either alternative or scientific conceptions about natural selection and biological adaptation in a particular task context. In the light of these results at least two conclusions can be drawn with regard to the construction of assessment tools: (1) the effect of task context on evolutionary explanations has to be better understood, (2) there is a clear need to control item features like context.

Our objective is the construction of an assessment instrument taking context as critical item feature into account. The study consists of three steps. (1) We use  a cognitive linguistics approach to better comprehend students’ context dependent explanations. For this purpose two idealized cognitive models that describe the sense of the words “adaptation” and “selection” in everyday language have been developed [2]. The models were used to deduce predictions for students’ application of alternative conceptions of selection/adaptation. (2) The predictions were tested in an explorative qualitative study with group discussions (12 groups, 3 students in each group, age 14 – 16). Four parallel sets of tasks about evolutionary phenomena were applied. Sets only differ in context. Data were analysed by qualitative content analysis [3]. Results will be integrated in the development of a quantitative assessment instrument (3).

Results of the qualitative study show a distinct influence of those task context features on students´ explanations that were predicted by the cognitive linguistic analysis (hint to (a) variation in populations, (b) experience of selection/adaptation in everyday life, (c) source and/or target of an evolutionary process and (d) the ascription of perceptive capacity of an organism). For example, given a hint to b students predominantly explain adaptation as a training effect and as an intentional process as expected by our cognitive model. Additional hints to a scientific concept like variation have no effect on students’ utterances. We conclude that precise understanding of the semantics of adaptation/selection in everyday life could help explaining students’ utterances and could add benefits to the construction of assessment instruments. 

[1] Nehm, R; Ha, M. (2011). Item Feature Effects in Evolution Assessment. JRST, 48 (3). 237-256. 

[2] Lakoff, G. (1990). Women, Fire, and Dangerous Things: What Categories Reveal About the Mind. University of Chicago Press. Chicago.

[3] Mayring, P. (Hrsg.) Die Praxis der qualitativen Inhaltsanalyse, 172–189. Weinheim, Basel: Beltz.