Saturday, 30 January 2016

Three reasons behind common misconceptions in biology

Recently I saw a link to an interesting news article about biology students' misconceptions of the subject. When I read the article I noticed that many of the misconceptions identified chimed with observations I have made of my own students' misconceptions. Intrigued, I downloaded the original research article on which the news item was based, which can be found hereThe authors identify three common underlying causes, or cognitive construals, for these misconceptions, each of which I will look at in turn.
Rafflesia, a parasitic plant (Photo credit: Dick Culbert)

1. Teleological thinking

The first common underlying cause of misconceptions, teleological thinking, refers to our need for causal stories behind the observation of phenomena, based on the assumption of goals, purposes, or functions. An example of this underlies one of the most common misconceptions I come across from students when teaching evolution. Here is a sentence I might commonly see from a student who is explaining the evolution of the body form of dolphins:

'The ancestor of dolphins walked on land but lived near water. Eventually dolphins adapted themselves so they could swim in the water'. 

Here, the student is assuming a purposeful effort from a dolphin ancestor to change itself into a form more suited to a life aquatic. Clearly this represents a fundamental misconception of natural variation, natural selection, and changes in the makeup of a population over time. Individual organisms cannot 'adapt themselves' to their environment. Natural variation in a population means that some individuals may be better suited to their environment and are therefore more likely to survive and reproduce. The traits that make them more fit for their environment therefore become more prevalent in the population. 

This is a tricky concept for native speakers to express correctly, and would seem to be linked to the underlying teleological misconception that evolution is a purposeful process. For my students, who are ELLs, they have to cope with both the difficulty of the concept and the use of language to correctly express it. Knowing the nature of this misconception, however, will enable me to help learners address these issues when they encounter them in the future. 

2. Essentialist thinking

The second type of misconceptions are related to essentialist thinking - a set of assumptions an individual may make about concepts, such as the idea that a particular feature of a system is solely responsible for defining its overall identity. In biology, an example of this would be the misconception that all plants are photosynthetic. Rafflesia, the plant which produces the largest flower in the world, is parasitic and does not make carbohydrates through photosynthesis. In fact, in biology there is frequently an exception to every 'rule'. Thus we need to help move students' understanding away from the idea that systems or processes need not be defined by a particular characteristic most of them share. 

3. Anthropocentric thinking

The third misconception occurs when biological phenomena are viewed through an anthropocentric, or human-centred lens. A common anthropocentric misconception which I have been battling for a long time now, and remember being used as an example of science undergraduates' misconceptions during my MAEd, is that plants take in food from soil via their roots. This misconception can be addressed simply by asking students if this were the case, why then are there not enormous holes in the ground at the base of every tree on the school grounds? However, knowing that the underlying, anthropocentric reason for this misconception - that all organisms, including plants, must 'eat' food in a similar way to humans - is helpful, and provides a means for approaching similar anthropocentric misconceptions. 

Summary

The insights afforded by understanding the underlying causes of common misconceptions among biology students are both interesting and helpful. Interesting, in that these misconceptions would appear to be widespread, irrespective of culture or language (although there may of course be some communities where they may not be present. Helpful, in that by understanding the underlying causes of these misconceptions, it can provide biology teachers with a means with which to address them. In turn, once learners become more aware of these causes, they too may be able to spot them more easily and avoid falling into these common traps. 

I would love to hear others' experiences of common misconceptions and ways of dealing with them.