The role of prior knowledge

One of the main challenges in teaching first year university students is that they have a great variety of backgrounds. A quick survey of any year one class will likely yield students who have come straight from school, students returning to education, and students who have taken a circuitous route through pre-university courses. Even the main block of students coming directly from school are a diverse group. Different school systems mean students can cover different content, and even that is assuming they take that subject at all. Those challenged with teaching first years know this better than those who take modules only in later years, when the group of students becomes somewhat more homogeneous.

All of this makes it difficult for the first year lecturer to approach their task, facing students who have, in our case, chemistry knowledge ranging from none at one extreme to a significant part of the syllabus they will be taking at the other.  As well as trying to navigate a syllabus that doesn’t isolate the novice learners and bore those who have “done it before”, there is a conceptual basis for worrying about this as well. Back in the 1950s, David Ausubel stated that the most important single factor influencing learning is what the learner already knows. Learners overlap new information with some existing knowledge, so that an ever-increasing complex understanding of a topic can develop. Unfortunately for novice learners, substantial unfamiliarity emphasises the attraction of rote learning, meaning that new information learned for the purpose of an exam and not integrated with some prior knowledge will likely be quickly forgotten, never mind understood.

In my own work (CERP, 2009, 10, 227-232), I analysed the performance of first year students in their end of module exam, and demonstrated that there was a consistent significant difference between the grades achieved by students who had taken chemistry at school and those that hadn’t. This difference disappeared from Year 2 onwards, suggesting that the group had levelled out somewhat by the end of the year. The response to this was to introduce pre-lecture activities so that students could at least familiarise themselves with some key terminology prior to lectures; a small attempt to generate some prior knowledge. Even this minor intervention led to the disappearance of any significant difference in exam scores (see BJET, 2012, 43(4), 2012 667–677).

I was reminded of all of this work by an excellent recent paper in Chemistry Education Research and Practice from Kevin de Berg and Kerrie Boddey which advances the idea further. Teaching nursing students in Australia, the researchers categorised the students as having completed senior school chemistry (SC), having completed a 3 day bridging course (BC) and having not studied chemistry since junior years of school (PC for poor chemistry). Statistical analysis showed some unsurprising results: those students with school chemistry scored higher (mean: 67%); followed by the bridging course students (54%); and lastly those students with poor chemistry (47%). The difference between BC and PC students was not significant however, although there were more lower performing students in the latter group.

These results align well with prior work on the value of prior knowledge in chemistry and the limited but positive impact of bridging courses. For me, this paper is valuable for its qualitative analysis. Students were interviewed about their experiences of learning chemistry. Those students who had completed the bridging course spoke about its value. For example, the authors quote Bella (please note, qualitative researchers, the author’s clever and helpful use of names beginning with B for Bridging Course students):

I think if I had actually gone straight just to class that first day not knowing anything, I don’t think I would have done half as well as what I would having known it.

Additionally, such was the perceived value of the bridging course, those students who had no prior chemistry felt left out. Paula states how she thinks it would have helped:

Familiarity in advance. Just, so you’re prepared. So you get the sort of basic, the basic framework of it all. So then, I’d sort of, got a head start and not be so overwhelmed…

Another interesting feature highlighted by students was the unique language of chemistry. Students spoke of entering their first chemistry class as being “like stepping into another world” and being “absolute Greek”. Additionally, the conceptual domains proved challenging, with students  overwhelmed by formulae and trying to visualise the molecular world. Pam states:

Maybe with anatomy, you can see more, you know, the things we’re cuttin’ up into pieces and looking inside. With chemistry, you can’t see it, so you gotta imagine that in your head and it’s hard tryin’ to imagine it, without actually physically touching it.

In a comprehensive review of prior knowledge, Dochy (1999) described “an overview of research that only lunatics would doubt“: prior knowledge was the most significant element in learning. Indeed, the review goes further when it considers strategies that teachers can use when considering students from differing backgrounds. I like this quote from Glaser and DeCorte cited elsewhere by Dochy:

Indeed, new learning is exceedingly difficult when prior informal as well as formal knowledge is not used as a springboard for future learning. It has also become more and more obvious, that in contrast to the traditional measures of aptitude, the assessment of prior knowledge and skill is not only a much more precise predictor of learning, but provides in addition a more useful basis for instruction and guidance’

This for me points a way forward. Much of the work on prior knowledge has concentrated on assessing the differences in performance as a function on prior knowledge or surveying the impact of amelioration strategies that aim to bring students up to the same level before teaching commences (such as bridging courses, pre-lecture activities, etc). But what about a more individualised learning path for students whereby a student’s starting point is taken from where their current understanding is. This would be beneficial to all learners – those without and also those with chemistry, the latter group could be challenged on any misconceptions in their prior knowledge. With technology getting cleverer, this is an exciting time to consider such an approach.