Be wary: animations risk embedding confused metaphors

One of the advantages of online material is the ability to include animations. This is particularly important for STEM applications, when animations can be used to show how systems work. For example, in my discipline (immunology) animations can be used to show how different cells interact, and how antibody molecules bind to their target and can be used to treat disease.

However, there are dangers to all these animations in that they can embed confusing metaphors at a very deep level in our students. Because of the potent strength of imagery and metaphor this can result in students having a profound misunderstanding of how things work.

One of the areas that I teach is the use of antibodies to treat cancer. Practically every animation or diagram that is produced (including by me!) shows the antibody molecules moving towards the cancer cells like heat-seeking missiles.

This is fundamentally wrong. Antibodies have no way of sensing where their target is, and they have no propulsion system that can move them to where they want to go. However, these images build on an old simile by Paul Ehrlich where he described antibodies as being like magic bullets that seek out their targets.

I have suggested that this metaphor is confusing, and that antibodies should be thought of more as ‘sticky drunkards’ that blunder around the body until by chance they bump into their target and stick to it.

Why is this important? In my experience of teaching students at all levels on how antibodies can be used to treat cancer, I find that many of them have a deep belief that antibodies behave like a heat-seeking missile or a magic bullet, and not like a sticky drunkard.

Educators who either produce that material, or use it, need to be aware of the simplifications and the dangers that they may be implanting incorrect concepts in our students.

This has practical consequences. If you want to kill a tumour cell with a magic bullet then you need only inject one bullet, as it will find that tumour cell wherever it is in the body. If you want to kill it with sticky drunkards then you need to inject a lot of them into a patient, as it is only by them randomly diffusing through the body that they can encounter that cell.

In my experience students often do not think enough about the consequences of this in designing or understanding experiments or treatments. They have been fundamentally misled by the metaphors that we have used to teach them, which include the visual animations as well as diagrams in textbooks and lectures.

It is vital to use diagrams, animations, and metaphors in teaching, but they can never show the entire truth. We have to simplify what we are explaining to give the essential points that are needed for our students’ understanding, stripping out information that is not directly relevant to the issue at hand. We have to give them metaphors that inspire them and illuminate their understanding.

However, we need to think through and be aware of these simplifications and what the hidden assumptions are so that we can show our students their limitations.

We need to be less lazy and more imaginative about the images that we use and the way in which we describe things. If you open an online resource or a text book, too often you see the same types of diagram or animation used to describe some process or system. There is a surprising, and rather depressing, lack of diversity.

If we gave our students more variety then they might understand that any one animation or image represented a partial view of the truth and needed complementing by others. They might (indeed we might!) develop more flexibility in thinking to use different imagery and metaphor to challenge their (our) deep assumptions.

Any image or animation used in education contains necessary simplifications – they cannot encapsulate all the complexity of the ‘real’ situation. But educators who either produce that material, or use it, need to be aware of the simplifications and the dangers that they may be implanting incorrect concepts in our students.

Andrew George is Deputy Vice-Chancellor and Professor of Immunology at Brunel University London