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Implicit Teaching

Tomorrow's Teaching and Learning

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The opposite of making facts, concepts and procedures explicit is to leave some of them implicit. This is what happens when we learn through discovery and inference. So ‘implicit teaching’ might be a good term to describe this approach, yet the expression does not seem to have caught on. Instead, implicit forms of teaching have many and various names, some exotic, others more commonplace.



The posting below looks at the concept of “implicit learning” which is what we mean by learning through discovery and inference..  It is from Chapter 6: Alternatives to Explicit Teaching, in the book, The Truth About Teaching: An Evidence-informed Guide for New Teachers, by Greg Ashman. SAGE Publications Ltd, 1 Oliver’s Yard, 55 City Road London EC1Y 1SP. Copyright © 2018 Greg Ashman. All rights reserved. Reprinted with permission.


Rick Reis

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Tomorrow’s Teaching and Learning

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Implicit Teaching - Alternatives to Explicit Teaching

Implicit teaching

The opposite of making facts, concepts and procedures explicit is to leave some of them implicit. This is what happens when we learn through discovery and inference. So ‘implicit teaching’ might be a good term to describe this approach, yet the expression does not seem to have caught on. Instead, implicit forms of teaching have many and various names, some exotic, others more commonplace.

At the time of writing, terms such as ‘problem-based learning’, ‘project-based learning’, ‘inquiry learning’ and even ‘makerspaces’ have become popular. Literacy teaching has its own set of labels, such as ‘balanced literacy’ and ‘critical literacy’. ‘Discovery learning’ is currently out of vogue, as is ‘whole language’. 

‘Constructivist teaching’ also seems to be on the way out, with many now arguing that constructivist learning theories do not necessarily imply an implicit teaching approach (see e.g. Mayer, 2004; Hattie, 2009). 

It is tempting to suggest that it is the relative ineffectiveness of implicit methods that makes it necessary for the frequent name changes. I couldn’t possibly comment on that, but I do think it is worth exploring some of the more popular implicit approaches in order to gain a sense of what they do and do not involve and what the evidence suggests.

Inquiry learning involves students conducting an investigation in response to a prompt or question. It can be applied to any subject area but has specific features when deployed in science or history lessons. In history, students might use historical sources to attempt to answer a question such as ‘How were Australian soldiers treated on their return from the Vietnam war?’ A typical science inquiry may be to figure out which brand of paper towels can absorb the most water or how the length of a pendulum affects the time it takes to swing. In science inquiries, students are expected to follow the scientific method, perhaps choosing which question to investigate themselves, formulating a hypothesis, planning a method and controlling variables in order to run a fair test.      

Notice that the objective of inquiry learning is to answer a question that is often quite complex and may draw upon abstractions. Knowledge will clearly need to be deployed in order to answer the question but the status of this knowledge is ambiguous; is the inquiry process intended to ensure that students gain this knowledge or is the knowledge simply a means to answering the question? Is the practice of inquiry perhaps an end in its own right?    

To some, inquiry is intended to meet all of these needs in parallel. Inquiry learning is seen as a process whereby students ‘learn content as well as discipline-specific reasoning skills and practices (often in scientific disciplines) by collaboratively engaging in investigations’ (Hmelo-Silver et al., 2007).     

It is worth returning to some of the potential pitfalls of relying too much on inquiry. As we saw in Chapter 5, evidence from the Programme for International Student Assessment (PISA) shows a correlation between an increased use of inquiry approaches and lower PISA science scores. We cannot be sure of the cause of this; it could be that students who struggle the most with science are more likely to be offered an inquiry-style course, perhaps because teachers and schools think they will find this motivating. However, this correlation should at least give us reason to pause.       

It certainly seems to be at odds with an understanding of cognitive science to assume that knowledge will be acquired in the process of completing something as complex as an inquiry (see Chapter 3). For example, in order to understand a source about how soldiers were received on their return from Vietnam, students would need to have some idea of why the soldiers were there in the first place, what they were doing and the political context in which this took place. And so we are reminded of Hirsch’s argument about the role of background knowledge in reading comprehension. No doubt some students will already possess the required understandings but if we rely on this then we are designing an inequitable system where the more advantaged will continue to learn whereas the least advantaged will not.  

So in order to run an equitable inquiry it is important to ensure that students have sufficient background knowledge of the subject into which they are inquiring, in advance. This is what happens in real life; when a physicist designs an experiment she may not know exactly what will happen in that particular experiment. However, she will know what has happened in a whole lot of similar precursor studies, she will know a great deal of relevant theory and she will be able to draw on this to make well-founded predictions about what is likely to happen. She is not operating in a vacuum, generating her hypotheses out of (very) thin air.       

This speaks to a role for inquiry that sits towards the end of a learning process. Rather than basinglearning in inquiry, it should work better as some kind of culminating task that builds on, and perhaps draws together, elements that have gone before. We will return to this theme later. In this sense, conducting an inquiry is much like writing an essay; it is a complex performance dependent upon skill in the numerous component parts.   

Nevertheless, inquiry questions could be beneficial from the beginning of a unit of work. At this stage, such prompts can help build a narrative and give purpose to a topic. 

Project-based learning is similar in many ways to inquiry learning. Here, the focus shifts away from answering a specific question to creating a product. However, if the product is a poster describing a history investigation then the two methods would become almost indistinguishable.      

Project-based learning and the Maker Movement (Dougherty, 2012), its technological sibling, sound like the very essence of all that is bright, new and shiny in the world of education. It is easy to be lifted away on a tide of soaring rhetoric; up and out of the dusty schoolrooms of the past and into a bright future full of beanbags, learning pods and white hot gadgetry. Yet there is very little that is new here. William Heard Kilpatrick was writing about ‘The Project Method’ back in 1918, extolling the virtues of the ‘purposeful act’ (Kilpatrick, 1918). Many modern proponents would no doubt acknowledge a debt to the early 20th century philosopher John Dewey. It is reasonable to ask why this revolutionary method has not yet delivered the predicted results.     

There is some promising evidence available from schools that have adopted project-based learning as part of a wider school agenda. For instance, ‘Expeditionary Learning’ schools incorporate projects, and reviews of the effectiveness of this model show potentially positive results (Borman et al., 2003; Comprehensive School Reform Quality Center, 2006). However, it is hard to untangle the projects themselves from other factors that vary between these schools and comparison schools. And, interestingly, the Expeditionary Learning model appears to use performance projects as the culmination of a unit of work, at least according to the curriculum units which are freely available online (Common Core Success, 2017). 

The Education Endowment Foundation (EEF), a UK charity established to generate evidence on educational interventions and guide schools in the use of this evidence, conducted a randomized controlled trial of a project-based learning approach developed by the Innovation Unit. Twelve schools were assigned to receive the intervention and 12 comparison schools were not. The results were not promising, with the EEF finding a potentially negative impact of project-based learning on the literacy of students eligible for free school meals. However, five schools left the intervention, contributing to nearly half of the students in the intervention group dropping out before the final analysis (Menzies et al., 2016). This high attrition rate casts doubt on the security of the findings and raises the interesting question of why so many schools decided to leave the programme.   

The other popular term for an implicit approach to teaching is ‘problem-based learning’. Again, it is worth stating that these labels are elastic and so the kind of mathematics teaching that is often described as ‘problem-based’ is also commonly referred to as ‘inquiry learning’ or even ‘project-based learning’ if tasks are distributed over a number of lessons. Further confusion abounds due to the common abbreviation for problem-based learning, ‘PBL’, being identical to that for project-based learning.     

The defining feature of problem-based learning is that students are presented with a problem to solve. This is usually, but not always, more contained than a project, so a problem will typically be the focus of a single lesson or a part of a lesson.   

In Chapter 3 we discussed the finding that relative novices generally learn more from studying worked examples than solving problems; a finding that does not bode well for attempts to base learning in problem solving. Nevertheless, the approach has proved popular with teachers and researchers and there are a number of studies that look at its effectiveness in different domains.     

Jo Boaler, currently a professor of mathematics education at Stanford University, has run a couple of interesting studies that seem to demonstrate the potential of teaching mathematics through problems. The first study took place in England and compared two schools that she called ‘Phoenix Park’ and ‘Amber Hill’. These two schools used very different approaches with Phoenix Park asking students to complete short projects based around interesting problems. Boaler found evidence that students at Phoenix Park developed superior conceptual understanding (Boaler, 1998).      

Boaler then conducted a similar study in California, this time involving three schools. Again, one of the schools used a problem-based approach and Boaler found that this had some advantages over the methods used by the other schools (Boaler, 2006). However, it is hard to draw any definite conclusions from such studies because many factors will have varied between the schools concerned, not just maths[MH2]  [E3] teaching methods. This is why randomized controlled trials of school-based approaches typically use a larger number of schools than in the Boaler studies; recall that the EEF included 24 schools in its trial of project-based learning.     

Problem-based learning has been widely adopted by medical schools for the education of nurses, doctors and other health professionals. For instance, students may be given a patient profile and list of symptoms and asked to figure out a diagnosis in groups, learning key knowledge and skills as part of the process. Helpfully, these methods have been subject to a significant body of research, which typically shows gains in some skills compared with conventional lecture-based university teaching, even if retention of knowledge is sometimes weaker for these students (Dochy et al., 2003).      

Jerry Colliver, a researcher at the Southern Illinois University School of Medicine, has been critical of a number of these studies due to possible confounds and other problems in their designs (Colliver, 2000). For instance, in some studies it appears that the students in the problem-based learning group were more able than the students they were being compared with, possessing, for instance, higher grade point averages. In one case, students in the problem-based learning group had frequent contact with patients whereas those in the traditional group had far less clinical experience by that stage of the course. Both groups were then assessed on clinical skills. The positive result in favour of the problem-based learning students therefore seems to rely on what I have called the ‘first principle of educational psychology’: students tend to learn the things you teach them and don’t tend to learn the things you don’t teach them.      

We may also suppose that problem-based learning would help develop a general skill of problem solving. Unfortunately, general problem-solving skills appear to be biologically primary and so it is unlikely that we can gain them in this way (Tricot and Sweller, 2014). If we move away from academic outcomes then there appear to be positive effects of problem-based learning on motivation (Norman and Schmidt, 1992). Yet it is always going to be hard to untangle these from the motivational effects of being involved in a study or of having teachers who are enthusiastic about the new methods they are trialling.


Boaler, J., 1998. Open and closed mathematics: student experiences and understandings. Journal for Research in Mathematics Education, pp. 41-62.

Borman, G.D., Hewes, G.M., Overman, L.T. and Brown, S., 2003. Comprehensive school reform and achievement: a meta-analysis. Review of Educational Research, 73(2), pp. 125-230.

Colliver, J.A., 2000. Effectiveness of problem-based learning curricula: research and theory. Academic Medicine, 75(3), pp. 259-66.

Common Core Success, 2017. EL Education. [online]

Dochy, F., Segers, M., Van den Bossche, P. and Gijbels, D., 2003. Effects of problem-based learning: a meta-analysis. Learning and Instruction, 13(5), pp. 533-68.

Dougherty, D., 2012. The Maker Movement. Innovations, 7(3), pp. 11-14.

Hattie, J.A., 2009. Visible Learning: A Synthesis of 800+ Meta-Analyses on Achievement. Abingdon: Routledge.

Hmelo-Silver, C.E., Duncan, R.G. and Chinn, C.A., 2007. Scaffolding and achievement in problem-based and inquiry learning: a response to Kirschner, Sweller, and Clark (2006). Educational Psychologist, 42(2), pp. 99-107.

Kilpatrick, W.H., 1918. The Project Method: The Use of the Purposeful Act in the Educative Process(No. 3). New York: Teachers College, Columbia University.

Mayer, R.E., 2004. Should there be a three-strikes rule against pure discovery learning? American Psychologist, 59(1), p. 14.

Menzies, V., Hewitt, C., Kokotsaki, D., Collyer, C. and Wiggins, A., 2016. Project Based Learning: Evaluation Report and Executive Summary. London: Education Endowment Foundation.

Norman, G.T. and Schmidt, H.G., 1992. The psychological basis of problem-based learning: a review of the evidence. Academic Medicine, 67(9), pp. 557-65.

Tricot, A. and Sweller, J., 2014. Domain-specific knowledge and why teaching generic skills does not work. Educational Psychology Review, 26(2), pp. 265-83.