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Deliberately introduced errors as a pedagogical tool: the teaching of energy flow

Anusha Krishnan

Incorrect diagram of energy flow through a forest ecosystem
Incorrect diagram of energy flow through a forest ecosystem   (Photo: Wernecke et al, doi: 10.1187/cbe.17-07-0133)

Don’t waste a good mistake; learn from it.” - Robert Kiyosaki, Author- Rich Dad, Poor Dad

Making mistakes is part and parcel of learning. If used constructively, errors can be a wonderful tool in a teacher’s stockpile of resources for instructing students. Another extensively used resource is visual presentation — the art of conveying an idea or concept with a picture, a diagram, or flow chart. A recent study from the University of Kiel in Germany shows that these two teaching aids can be combined to help students gain a better understanding of abstract concepts such as energy flows in ecosystems.

The study demonstrates that when students are given a flawed diagram explaining a concept and asked to spot and explain errors in it, they attain a better grasp of that concept than those asked to learn with accurate diagrams. However, this approach requires three specific conditions — that the symbology in a diagram must be absolutely clear, that students must already have a good understanding of the subject, and finally, students must be willing to study such diagrams closely and thoroughly.

The idea of deliberately introducing errors, a concept known as ‘negative knowledge’ or the ‘knowledge of how something is not, in contrast to how it really is’ has been applied in teaching mathematics, its use in classrooms to tackle conceptual misunderstandings however, is not widespread.

Amongst students, most errors occur due to partial understanding or misunderstandings in abstract concepts such as that of energy. When learning about energy flow in biological systems, many students harbor two major misconceptions – one, that plants can obtain energy from soil, and two, that energy can be cycled within an ecosystem. Using these misconceptions, researchers introduced the error in the form of an additional arrow (circled in the image above) and tested the effectiveness of three teaching strategies. In group one, students given a flawed energy-flow diagram were asked to find the error and explain why it was an error. A second group was given the flawed diagram with the error highlighted and were tasked with explaining the error. While in the third group, students were simply handed the correct diagram, and asked to learn about energy flow in an ecosystem. Students were tested on energy-flow concepts before the given task (pre-test), and once again after they completed the task (post-test). The differences in scores between the pre-test and post-test were used as a measure of how much students had learnt from the tasks.

Overall, students from all groups scored more in the post-test than the pre-test, indicating that they had gained an improved understanding of energy flow after the tasks. Closer analysis of the data showed that students from group 1 and 2 who had correctly explained the error seemed to have learnt more than students in group 3, or the unsuccessful students in groups 1 and 2.

The most striking finding was that only 10% of group 1 students were able to correctly identify and explain the error in the diagram. Compared to their peers who could not complete the task, these students had spent more time focusing on studying the diagram to spot the error. In contrast to group 1, nearly 30% of the students in group 2 explained the error correctly, indicating that spotting an error requires much more cognitive focus than having the error pointed out and needing to explain it. The researchers also found that the successful students in this group had better knowledge of energy concepts than others in the same group.

In essence, inserting errors in diagrams can help learning only if students successfully find and explain such errors. Furthermore, researchers found that students often misunderstood the symbology and labelling used in the diagrams. Therefore, for such a teaching strategy to succeed in helping students, three points must be ensured: 1. that students clearly understand the symbology and labelling in diagrams, 2. they have a good grasp of the subject, and 3. they must study the diagrams carefully, and in detail. It has been noted that when learning with visual aids like diagrams, many students tend to skim over the material without examining it in detail. Although not labelling the error in flawed diagrams may encourage students to put in more cognitive effort in studying the diagram and the concept, this does come with the danger of imparting wrong information. A student in a hurry may simply memorize the wrong facts without bothering to check the instructions accompanying the material.

In conclusion, deliberately introduced errors in visual aids can foster an error-tolerant classroom culture by showing that learning from errors is not only possible, but also desirable.