In a post entitled Why I’m happy to say that learning styles don’t exist Greg Ashman says that one of the arguments I used in my previous post about learning styles “seems to be about the semantics of falsification“. I’m not sure that semantics is quite the right term, but the falsification of hypotheses certainly was a key point. Greg points out that “falsification does not meaning proving with absolute certainty that something does not exist because you can’t do this and it would therefore be impossible to falsify anything”. I agree completely. It’s at the next step that Greg and I part company.
Greg seems to be arguing that because we can’t falsify a hypothesis with absolute certainty, sufficient evidence of falsification is enough to be going on with. That’s certainly true for science as a work-in-progress. But he then goes on to imply that if there’s little evidence that something exists, the lack of evidence for its existence is good enough to warrant us concluding it doesn’t exist.
I’m saying that because we can’t falsify a hypothesis with absolute certainty, we can never legitimately conclude that something doesn’t exist. All we can say is that it’s very unlikely to exist. Science isn’t about certainty, it’s about reducing uncertainty.
My starting point is that because we don’t know anything with absolute certainty, there’s no point making absolutist statements about whether things exist or not. That doesn’t get us anywhere except into pointless arguments.
Greg’s starting point appears to be that if there’s little evidence that something exists, we can safely assume it doesn’t exist, therefore we are justified in making absolutist claims about its existence.
Claiming categorically that learning styles, Santa Claus or fairies don’t exist is unlikely to have a massively detrimental impact on people’s lives. But putting the idea into teachers’ heads that good-enough falsification allows us to dismiss outright the existence of anything for which there’s little evidence is risky. The history of science is littered with tragic examples of theories being prematurely dismissed on the basis of little evidence – germ theory springing first to mind.
testing the learning styles hypothesis
Greg also says “a scientific hypothesis is one which makes a testable prediction. Learning styles theories do this.”
No they don’t. That’s the problem. Mathematicians can precisely define the terms in an equation. Philosophers can decide what they want the entities in their arguments to mean. Thanks to some sterling work on the part of taxonomists there’s now a strong consensus on what a swan, or a crow or duck-billed platypus are, rather than the appalling muddle that preceded it. But learning styles are not terms in an equation, or entities in philosophical arguments. They are not even like swans, crows or duck-billed platypuses; they are complex, fuzzy conceptual constructs. Unless you are very clear about how the particular constructs in your learning styles model can be measured, so that everyone who tests your model is measuring exactly the same thing, the hypotheses might be testable in principle but in reality it’s quite likely no one has has tested them properly. And that’s before you even get to what the conceptual constructs actually map on to in the real world.
This is a notorious problem for the social sciences. It doesn’t follow that all conceptual constructs are invalid, or that all hypotheses involving them are pseudoscience, or that the social sciences aren’t sciences at all. All it means is that social scientists often need to be a lot more rigorous than they have been.
I don’t understand why it’s so important for Daniel Willingham or Tom Bennett or Greg Ashman to categorise learning styles – or anything else for that matter – as existing or not. The evidence for the existence of Santa Claus, fairies or the Loch Ness monster is pretty flimsy, so most of us work on the assumption that they don’t exist. The fact that we can’t prove conclusively that they don’t exist doesn’t mean that we should be including them in lesson plans. But I’m not advocating the use of Santa Claus, fairies, the Loch Ness monster or learning styles in the classroom. I’m pointing out that saying ‘learning styles don’t exist’ goes well beyond what the evidence claims and, contrary to what Greg says in his post, implies that we can falsify a hypothesis with absolute certainty.
Absence of evidence is not evidence of absence. That’s an important scientific principle. It’s particularly relevant to a concept like learning styles, which is an umbrella term for a whole bunch of models encompassing a massive variety of allegedly stable traits, most of which have been poorly operationalized and poorly evaluated in terms of their contribution – or otherwise – to learning. The evidence about learning styles is weak, contradictory and inconclusive. I can’t see why we can’t just say that it’s weak, contradictory and inconclusive, so teachers would be well advised to give learning styles a wide berth – and leave it at that.