Convergent, divergent, bricks

Playing a hunch, I asked number 2 son how many uses he could think of for a housebrick. ‘You could slice it’ he said ‘and cook the slices.’

The question, which has haunted me for years, comes from a test devised by psychologist Liam Hudson, who drew on the work of J.P. Guilford. It appears from such tests that people tend to favour one of two styles of thinking, which Guilford called convergent and divergent production.

Divergent production?The ability to generate multiple solutions to a problem; creativity.

Convergent production?The ability to deduce a single solution to a problem; rule-following or problem-solving.

_ Wikipedia art: J. P. Guilford

Hudson’s work demonstrated that people (at least, English schoolboys – but he has studied other groups) tend to favour one style over another, and to exhibit different mixtures of the two. There is no such thing as a pure divergent thinker – such a person would not be able to solve the simplest problem – or a pure convergent thinker, one unable to get past the literal. The convergent-divergent distinction belongs to a group of others, such as the ‘multiple intelligences’ of Howard Gardner, whose general aim is to enrich our conceptions of thinking. It appears that once alerted to the two different styles, people can begin to help themselves. My son needed no help to come up with cooked slices of housebrick, and since as it happens, he’s very good at maths and science, in Hudson’s test he would probably show up in the fat part of the bell curve.

On the other hand, there’s Stefano Mazzochi, a thoughtful bloke who needed a kickstart. His test asked him to list all possible uses he could think of for a screwdriver.

What was interesting to me when I came across that test was how poorly I performed at first.

I could not think about any use of a screwdriver other than ?screwing/unscrewing a screw? and, say, ?open a can of paint?. It was only after reading other people?s responses such as ?a pole for a little flag?, ?a pin for a hinge?, ?an ice pick?, ?a weapon?, ?a percussion instrument? that I realized that I had been automatically applying my convergent mind onto a divergent test. Once I knew that I had to use my imagination, that the uses only needed to be even just remotely plausible, not optimal, I started to perform a lot better.

You can’t say on this showing that Mazzochi learnt how to think divergently; what he learnt was what counted as an appropriate response, and he was then able to deliver the goods. Educationists, take note!

But then, most of us can’t resist dichotomies: hedgehogs and foxes, Platonists and Aristotelians, liberals and authoritarians, introverts and extraverts. Whatever their ontological status, they certainly help when it comes to human beings.
‘One of these things is not like the other’ Big Bird used to say on Sesame Street, and most little kids would take pleasure in picking out the fish in a line-up of furry beasts. Pity the infant Platonist who lisps ‘But they’re all animals!’ and cries when Big Bird says it’s the fish and has to be bought off with cookies. The kid is right. What he needs to be taught that in this context that’s not the standard answer.

What started me thinking about all this was a piece in the New York Times about the human genome project. No sooner was the idea of genes familiar than people started saying that pretty soon we’d know ‘the gene for cancer’ or ‘the gene for homosexuality’. (Remember gays against gene research?) Now that the individual’s genome can be sequenced, those same people are looking forward to having their personal blueprint pinned up on the wall. ‘Hey look, that’s the bit that makes me forget where I put the car keys.’ One behaviour, one cause, one outcome. Convergent thinkers, rejoice: the self is a problem to which we have an answer.

As scientists come to understand more about the matter, however, the picture looks rather different, as the New York Times piece shows. In what is called the ‘consensus genome’ – the structure that makes a human being as distinct from a fish – some lines of causation can certainly be traced. The genomic structures for a particular individual are something else again.

It is a bit misleading to speak of the human genome. One of the most constant observations of daily life is just how different we all are. These differences are present at the level of our genomes as well, and lead to all sorts of questions about what is captured in the ?consensus? genome.

The consensus genome sequence also fails to capture the tremendous amount of information encoded in the ?physical genome? ? that is to say, the specific geometry of the DNA molecule in the nucleus. The genome is wrapped up on spools called nucleosomes, which are in turn bound up into other structures called chromatin, and this physical packaging has significant but poorly understood effects on biological properties one usually tries to abstract, such as gene expression, cell fate decisions and cellular growth.

That ain’t the half of it according to one commenter on Quake’s piece: you must also consider the epigenome, the transcriptome, copy-number variation,and the metabolome. Whatever those are.

So – and this is where I circle back to Hudson and cooked slices of brick – in the debates about the origins of human differences, the tensions between diversity-people and uniformity-people – between Steven Pinker and Richard Lewontin – cannot be resolved in the present state of science. What psychological science can do, however, is to suggest why such debates get going in the first place, and why sometimes it feels as if arguing with people with different views is simply futile. What’s a brick for? Why, to build a wall.