It’s a fairly well established principle of cognitive science that experts and novices think differently. Being aware of these differences can make a big difference to teachers. For instance, if we assume that most children in most situations are likely to begin as novices this could help point the way to more effective instruction. Here’s a summary of some of the main differences between experts and novices.
One of the most interesting findings to come out of the research into Cognitive Load Theory is the finding that experts and novices both experience cognitive overload, but experience it differently. Novices, by definition, lack knowledge and experience in the domain they are trying to solve problems in. This means they lack the robust, interconnected schema in long term memory which allows experts to overcome the limits of working memory. As John Sweller puts it, “Novices, not possessing appropriate schemas, are not able to recognize and memorize problem configurations and are forced to use general problem-solving strategies such as means-ends analysis when faced with a problem.” Means-end analysis is likely to lead to cognitive overload because it involves trying to work through and hold in mind multiple possible solutions. A bit like trying to juggle 5 objects at once without any practice.
The implication of Sweller’s research into CLT indicates that novices will benefit from explicit explanations, worked examples, goal free problems, and fully guided instruction. For an excellent overview of the strategies most likely to benefit novices learners see Oliver Caviglioli’s Teaching HOW2s. So far so good. However, the research of Slava Kalyuga and others has suggested that these techniques actually increase cognitive load for experts.
What’s become known as the ‘expertise reversal effect‘ predicts that as we acquire the schema needed to free up working memory capacity, we start to benefit from less instruction and more freedom. Essentially, what’s effective at helping students to acquire schema becomes unhelpful once schema have been acquired. So, the advice is to use fully guided instruction with novices and discovery approaches with experts.
But how do teachers know when their students have crossed the threshold into expertise? I was tagged in to an interesting Twitter debate recently on what it means to be an expert:
I’ve been reading up on the expertise reversal effect. Struggling, as there seems to be little shared understanding of what constitutes an expert. Does this differ from study to study? Any suggestions? @HFletcherWood @cbokhove @Nick_J_Rose @DavidDidau @dylanwiliam @greg_ashman
— Nick Wells (@NSMWells) February 15, 2018
For Anders Ericsson, an expert is someone who has achieved true mastery of their subject and has probably spent at least 10 years engaged in deliberate practice. Clearly, this definition is unlikely to apply to many school students. In a classic experiment conducted by Michelene Chi and colleagues, two groups were given a series of physics problems to sort in any way they wished. The first group consisted of physics undergraduates who sorted the problems by their surface features. The experts, who were able to categorised the problems by their deep structure, were physics postgraduates. Again, this is not a situation we’re likely to encounter with school-age children. So, should we just not worry about this at all and treat all students like novices all the time?
Well, probably not. Christian Bokhove shared this paper from Robert Plomin and colleagues in which 12-year-olds with “exceptional performance on a battery of reading tests such as fluency and comprehension” are identified as expert readers. It stands to reason that if a 12-year-old is reading at the level of an expert then it would be ridiculous to give her detailed, explicit instructions on how to read. From this we can infer that expertise is relative; some students will have acquired more robust schemas than others and therefore it might make sense to use our aware of the expertise reversal effect to treat them differently.
Sweller suggests that in order to minimise extraneous cognitive load, instructional design should address the needs of three broad groups of expertise:
- Novice level – “detailed, direct instructional support…preferably in integrated or dual-modality formats”
- Intermediate level – “a mix of direct instruction and problem-solving practice with reduced support”
- Advanced level – “minimally guided problem-solving tasks…provide cognitively optimal instructional methods” (Cognitive Load Theory, Chapter 12)
This gradual reduction of structure from novice to advanced level is termed the ‘guidance fading effect’ which makes use of ‘completion tasks’ to bridge the gap from worked examples to unguided problem-solving. This involves giving students partially worked examples to complete with the partial working helping to support limited working memory and the missing information requiring students to engage in retrieval practice and deeper process thinking.
Asking when students become experts is probably the wrong question; in any meaningful sense, school-children are not experts. Instead teachers might do best to think about students becoming more advanced, and engage protracted baton passing exercise where we assume that students are building up the relevant schemas required for more advanced problem-solving unless proved otherwise. As students become more confident at tackling problems within a subject we should remove scaffolding and support as rapidly as possible, but stand ready to put it back if they struggle too much.
In this post I discussed how this approach might look in regards to how and why we give students feedback, and I’m reasonably sure that the same principle will apply to all aspects of instruction:
So, how do we know if students are becoming more advanced? Assessment. If students perform fluently in one lesson, this does not necessary mean they will remember well enough to perform well the next. We should always assume that schema need to be reinforced and encourage students not to practice until the solve a problem correctly, but to continue practising until they can no longer get it wrong. And if they cannot answer or solve a problem, more explicit instruction is clearly required.
Teaching a class of children is always an uncertain enterprise, and we’ll never know precisely who is where on the journey towards mastery in all the various aspects of the subjects we teach. This doesn’t really matter, as long as we are prepared to see expertise as a quality of the topic not the individual. My best advice is this: don’t let students struggle until they have experienced some measure of success.