The power of comparison

absoluterelativeImage: @jasonramasami
There is no quality in this world that is not what it is merely by contrast. Nothing exists in itself.

– Hermann Melville

Would white exist if there was no black? Would happiness be possible without sadness? Could a congenitally blind person ever conceptualise the difference between light and dark?

These are age-old philosophical questions that I certainly do not claim to have the answers to. Nevertheless, they shine a light on a fascinating area of human learning and judgement: the way our mind copes well with comparisons and poorly with absolutes. This was the subject of Daisy Christodoulou’s recent post on why it is so much easier to assess a student’s work by comparing it with another than by judging it against a marking rubric. Research into this area suggests that the human brain is not designed to make absolute judgements and works far better when making comparisons. That’s why we find it much easier to put students’ essays into ascending order of quality than to use a mark scheme to grade a single essay.

I think that the comparison approach also has other implications for teachers. The evidence from cognitive science into interleaving – mixing related but distinct material – is fascinating. Although it would seem logical to focus on one topic or problem-type at a time, the opposite appears to have a more beneficial effect on learning. In a number of fields – from distinguishing between bird species, to baseball hitting, to geometrical problems – mixing problems has been shown to lead to more learning than presenting problems in discreet blocks. Even more intriguing, as Benedict Carey writes in his engaging book How We Learn: The Surprising Truth About When, Where and Why it Happens, is that “The mixing of items, skills, or concepts during practice, over the longer term, seems to help us not only see the distinctions between them but also to achieve a clearer grasp of each one individually.” (See this paper for further reading.)

On an anecdotal level, I have always found I find it easier to understand and conceptualise ideas when I think of them in contrast. However, it is doubly important to me as an English teacher. Antithesis and juxtaposition are staples of the writing craft, while conflicts and tensions sizzle at the heart of the best literature.  The study of literature is all about teasing out and exploring the relationships between ideas, and the most successful students are those who can pinpoint very subtle shades of difference.

Indeed, to gain a broader understanding of literary form and style young people must read a wide range of texts, from a range of writers, over a range of eras. The more we read, the more examples we have to draw from and the easier it becomes to notice the idiosyncracies of authorial style and intention.
There are many simple ways to harness the comparison effect in your teaching. The following focus on English teaching but could be adapted to suit other subjects too:
  • Explore characters in pairs – e.g. consider how J.B. Priestley contrasts Sheila Birling with Eva Smith. Even better, compare characters across texts and historical eras – Arthur Birling with Scrooge, for example.
  • Compare beginnings and ends. Too often students write absolute comments about a text or character based on a single event or quotation without considering the changes and developments that occur further down the line. One way round this is to regularly compare, say, the first line of a poem with its last.
  • Teach themes as binary oppositions rather than absolutes. In other words, avoid singular themes: hope, love, time, etc. Try hope vs. despair, appearance vs. reality, lust vs. love instead. (And don’t forget all those shades of grey in between too!)
  • Use comparative models. Get students to compare good and bad examples of writing on the same topic before they write their own pieces – see more here.
  • Ask comparative questions. I’ve nicked this one from Dylan William’s Embedded Formative Assessment. Rather than ask “What is a noun?”, ask “How is noun different from a verb?” Or, rather than “What do you think about Slim?”, ask “How does Slim compare to Curley?”
  • Highlight the subtle differences between synonyms. It’s easy tell the difference between ‘intelligent’ and ‘foolish’; however, asking students to investigate the difference between ‘perceptive’ and ‘intelligent’ is far more rigorous.

There are plenty of simple ways we can harness the power of comparison; in doing so, our classes can dissect ideas with a far finer scalpel.

Thanks for reading.