{"id":7003,"date":"2023-03-07T08:00:45","date_gmt":"2023-03-07T13:00:45","guid":{"rendered":"https:\/\/braindevs.net\/blog\/blog\/?p=7003"},"modified":"2023-03-07T10:08:52","modified_gmt":"2023-03-07T15:08:52","slug":"when-prior-knowledge-bites-back-the-dangers-of-knowing-too-much","status":"publish","type":"post","link":"https:\/\/www.braindevs.net\/blog\/when-prior-knowledge-bites-back-the-dangers-of-knowing-too-much\/","title":{"rendered":"When Prior Knowledge Bites Back: The Dangers of Knowing Too Much"},"content":{"rendered":"

In this blog, we typically highlight the benefits of prior knowledge<\/em>.<\/p>\n

For example: if a student knows a lot about baseball, she\u2019ll be much more successful in understanding a reading passage about baseball.<\/p>\n

\"Young<\/a><\/p>\n

That same student could struggle mightily with a passage about cricket. What\u2019s an \u201cover\u201d? A \u201cwicket\u201d? A \u201cbadger\u201d?<\/p>\n

In the world of cognitive load theory<\/strong>, prior knowledge helps because it reduces working memory load.<\/p>\n

An expert knows relevant definitions, concepts, procedures \u2013 and the relationships among them.<\/p>\n

And because experts have all that knowledge in long-term memory<\/em>, they don\u2019t need to noodle it around as much in working memory<\/em>.<\/p>\n

The teaching implications of this insight:<\/p>\n

First<\/strong>: find out how much prior knowledge students have on any given topic.<\/p>\n

Second<\/strong>: ensure student have the prior knowledge they need before starting on any given topic. Don\u2019t start it until they do.<\/p>\n

NB: This second insight has important implications for many project pedagogies.<\/p>\n

This conclusion is well settled in cognitive load theory. But: is it always true?<\/p>\n

Is it possible that prior knowledge might increase<\/em> working memory load? Could it make thinking and problem solving more difficult<\/em>?<\/p>\n

Thinking the Unthinkable<\/h2>\n

Here\u2019s a question:<\/p>\n

\u201cTo mitigate the effects of climate change, would it be a good idea to plant more Douglas fir, oak, and beech trees in the Black Forest?\u201d<\/p><\/blockquote>\n

I know a bit about climate change, and a bit about trees, and I\u2019m generally inclined to say \u201cyes.\u201d Because I\u2019m a novice<\/strong> \u2013 that is, I don\u2019t have lots of prior knowledge on these topics \u2013 the question strikes me as straightforward.<\/p>\n

However, if I were an expert, I might draw on my prior knowledge to see additional complexities in the question<\/em>.<\/p>\n

For instance…<\/p>\n

…those trees might be vulnerable to particular diseases or pests,<\/p>\n

…they might harm the ecosystem in the Black Forest,<\/p>\n

…they might \u2013 paradoxically \u2013 do some tree thing or another that would ultimately exacerbate climate change rather than mitigate it.<\/p>\n

In this case, an expert\u2019s prior knowledge could introduce complicating variables \u2013 and thereby increase<\/em> working memory load.<\/p>\n

A research team, made up of scholars from Germany and Australia*, tested this hypothesis<\/a>.<\/p>\n

As you would expect, they asked forestry experts and forestry non-experts to consider (roughly) the tree-planting question above.<\/p>\n

The experts considered the question more complicated<\/em> than the novices did. That is: that said that it required more thought, more simultaneous contemplation of variables, and more complex thinking..<\/p>\n

And \u2013 here\u2019s the kicker \u2013 their answers weren\u2019t any better than the novice\u2019s answers<\/em>.<\/p>\n

In Other Words<\/h2>\n

Putting all these pieces together\u2026<\/p>\n

Forestry experts’ higher level of prior knowledge increased their perception of the problem\u2019s complexity;<\/em><\/p>\n

It did so (probably) because they thought of additional variables not included in the question;<\/p>\n

These additional variables increased working memory load<\/em>;<\/p>\n

Because of additional strain on working memory, these experts didn\u2019t benefit from their prior knowledge \u2013 and didn\u2019t answer the question more effectively than novices.<\/p>\n

Wow.<\/p>\n

The research team then went ahead and tested this same idea with 4th<\/sup> graders in Australia.<\/p>\n

As often happens in research, the details get complicated. The headline is: when they tested a classroom analog of the same problem, they got somewhat similar results.<\/p>\n

Students with higher levels of prior knowledge DID perceive the cognitive load to be higher.<\/p>\n

However, when those students solved problems, they scored higher than when they did not have relevant prior knowledge. (Remember: for the forestry example, higher cognitive load eliminated the experts\u2019 advantage in solving the problem.)<\/p>\n

In other words: the potential dangers of prior knowledge do show up in the classroom, not just in abstract research exercises.<\/p>\n

Teaching Implications, Take II<\/h2>\n

Above I wrote:<\/p>\n

First<\/strong>: find out how much prior knowledge students have on any given topic.<\/p>\n

Second<\/strong>: ensure student have the prior knowledge they need before starting on any given topic. Don\u2019t start it until they do.<\/p>\n

Based on this study, I think we should add another implication:<\/p>\n

Third<\/strong>: stop and consider \u2013 how might a student\u2019s expert prior knowledge interfere<\/em> with their learning of this concept? What other concepts or procedures might they draw into a question in ways that unhelpfully complicate their thinking?<\/p>\n

At this point, I don\u2019t think we have enough research into the dangers of prior knowledge to have refined or thorough guidance in answer to those new questions.<\/p>\n

I do think, however, we should get in the habit of asking them.<\/p>\n

TL;DR<\/strong><\/p>\n

Typically, prior knowledge benefits students <\/em>by reducing working memory load<\/em>.<\/p>\n

Therefore, typically, we should ensure they have relevant prior knowledge before starting a topic.<\/p>\n

In some cases \u2013 according to this research \u2013 prior knowledge can complicate thinking<\/em> when experts bring in too many ideas from their knowledge base.<\/p>\n

In these cases, we should be sure to think through those potential dangers, and head them off as best we can.<\/p>\n

And: we should follow this research pool. It\u2019s an intriguing topic!<\/p>\n

\n

* One of the researchers here is none other than Ollie Lovell, who wrote an EXCELLENT book on Cognitive Load Theory for teachers. You can read my review here<\/a>.<\/p>\n

\n

Endres, T., Lovell, O., Morkunas, D., Rie\u00df, W., & Renkl, A. (2022). Can prior knowledge increase task complexity?\u2013Cases in which higher prior knowledge leads to higher intrinsic cognitive load.\u00a0British Journal of Educational Psychology<\/i>.<\/p>\n","protected":false},"excerpt":{"rendered":"

In this blog, we typically highlight the benefits of prior knowledge. For example: if a student knows a lot about baseball, she\u2019ll be much more successful in understanding a reading passage about baseball. That same student could struggle mightily with a passage about cricket. What\u2019s an \u201cover\u201d? A \u201cwicket\u201d? A \u201cbadger\u201d? In the world of […]<\/p>\n","protected":false},"author":18,"featured_media":7006,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[41,30],"class_list":["post-7003","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-lb-blog","tag-experts-and-novices","tag-working-memory"],"_links":{"self":[{"href":"https:\/\/www.braindevs.net\/blog\/wp-json\/wp\/v2\/posts\/7003","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.braindevs.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.braindevs.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.braindevs.net\/blog\/wp-json\/wp\/v2\/users\/18"}],"replies":[{"embeddable":true,"href":"https:\/\/www.braindevs.net\/blog\/wp-json\/wp\/v2\/comments?post=7003"}],"version-history":[{"count":4,"href":"https:\/\/www.braindevs.net\/blog\/wp-json\/wp\/v2\/posts\/7003\/revisions"}],"predecessor-version":[{"id":7008,"href":"https:\/\/www.braindevs.net\/blog\/wp-json\/wp\/v2\/posts\/7003\/revisions\/7008"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.braindevs.net\/blog\/wp-json\/wp\/v2\/media\/7006"}],"wp:attachment":[{"href":"https:\/\/www.braindevs.net\/blog\/wp-json\/wp\/v2\/media?parent=7003"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.braindevs.net\/blog\/wp-json\/wp\/v2\/categories?post=7003"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.braindevs.net\/blog\/wp-json\/wp\/v2\/tags?post=7003"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}