A discussion on Twitter raised a lot of questions about working memory and the evidence supporting direct instruction cited by Kirschner, Sweller and Clark. I couldn’t answer in 140 characters, so here’s my response. I hope it covers all the questions.
Kirschner Sweller & Clark’s thesis is;
• working memory capacity is limited
• constructivist, discovery, problem-based, experiential, and inquiry-based teaching (minimal guidance) all overload working memory and
• evidence from studies investigating efficacy of different methods supports the superiority of direct instruction.
Therefore, “In so far as there is any evidence from controlled studies, it almost uniformly supports direct, strong instructional guidance rather than constructivist-based minimal guidance during the instruction of novice to intermediate learners.” (p.83)
Sounds pretty unambiguous – but it isn’t.
1. Working memory (WM) isn’t simple. It includes several ‘dissociable’ sensory buffers and a central executive that monitors, attends to and responds to sensory information, information from the body and information from long term memory (LTM) (Wagner, Bunge & Badre, 2004; Damasio, 2006).
2. Studies comparing minimal guidance with direct instruction are based on ‘pure’ methods. Sweller’s work on cognitive load theory (CLT) (Sweller, 1988) was based on problems involving use of single buffer/loop e.g. mazes, algebra. New items coming into the buffer displace older items, so buffer capacity would be limiting factor. But real-world problems tend to involve different buffers, so items in the buffers can be easily maintained while they are manipulated by the central executive. For example, I can’t write something complex and listen to Radio 4 at the same time because my phonological loop can’t cope. But I can write and listen to music, or listen to Radio 4 whilst I cook a new recipe because I’m using different buffers. Discovery, problem-based, experiential, and inquiry-based teaching in classrooms tends to more closely resemble real world situations than the single-buffer problems used by Sweller to demonstrate the concept of cognitive load, so the impact of the buffer limit would be lessened.
3. For example, Klahr & Nigam (2004) point out that because there’s no clear definition of discovery learning, in their experiment involving a scientific concept they ‘magnified the difference between the two instructional treatments’ – ie used an ‘extreme type’ of both methods – that’s unlikely to occur in any classroom. Essentially they disproved the hypothesis that children always learn better by discovering things for themselves; but children are unlikely to ‘discover things for themselves’ in circumstances like those in the Klahr & Nigam study.
It’s worth noting that 8 of the children in their study figured out what to do at the outset, so were excluded from the results. And 23% of the direct instruction children didn’t master the concept well enough to transfer it.
That finding – that some learners failed to learn even when direct instruction was used, and that some learners might benefit from less direct instruction, comes up time and again in the evidence cited by Kirschner, Sweller and Clark, but gets overlooked in their conclusion.
I can quite see why educational methods using ‘minimal instruction’ might fail, and agree that proponents of such methods don’t appear to have taken much notice of such research findings as there are. But the findings are not unambiguous. It might be true that the evidence ‘almost uniformly supports direct, strong instructional guidance rather than constructivist-based minimal guidance during the instruction of novice to intermediate learners’ [my emphasis] but teachers aren’t faced with that forced choice. Also the evidence doesn’t show that direct, strong instructional guidance is always effective for all learners. I’m still not convinced that Kirschner, Sweller & Clark’s conclusion is justified.
Damasio, A (2006) Descartes’ Error. Vintage Books
Klahr, D & Klahr, D, & Nigam, M. (2004). The equivalence of learning paths in early
science instruction: Effects of direct instruction and discovery learning.
Psychological Science, 15, 661–667.
Sweller, J. (1988). Cognitive load during problem solving: Effects on learning.
Cognitive Science, 12, 257–285.
Wagner, A.D., Bunge, S.A. & Badre, D. (2004). Cognitive control, semantic memory and priming: Contributions from prefontal cortex. In M. S. Gazzaniga (Ed.) The Cognitive Neurosciences (3rd edn.). Cambridge, MA: MIT Press.