"Bear in mind that the wonderful things you learn in your schools are the work of many generations, produced by enthusiastic effort and infinite labor in every country of the world. All this is put into your hands as your inheritance in order that you may receive it, honor it, add to it, and one day faithfully hand it to your children. Thus do we mortals achieve immortality in the permanent things which we create in common." - Albert Einstein

Monday, March 11, 2013

The Learning Pyramid: A Hoax People Like to Believe

When I started graduate school in Illinois, I first joined a synthetic group in inorganic chemistry. My assignment then was to prepare the first compound in which the noble gas xenon was covalently bound to carbon. Among the noble gases, xenon had a considerably low ionization potential and twenty five years before my graduate studies, Bartlett showed that xenon reacted with platinum hexafluoride. While planning our course of action, I would never forget what my mentor told me. He said, "In research, you would find yourself trying out a hundred experiments that would not work before you would stumble at success, so you need to work hard." Perhaps, that was an exaggeration. However, negative results are rarely published so no one really knows exactly how many experiments have failed before publishable results are finally obtained. From my experience, I would say that there are quite a number of failures. Such is discovery.

It therefore amazes me to see how great emphasis is usually given in discovery-based learning. In synthesizing the first compound where xenon is attached to carbon, starting from scratch would make this endeavor even far more difficult. Naumann and Tyrra synthesized the first compound with a stable xenon-carbon bond. And they used xenon difluoride and tris(pentafluorophenyl)borane to make this compound. Scientists do not work from scratch. A major part of discovery is learning from the past, "standing on the shoulders of giants". Scientists read. Scientists attend lectures. Yet, in learning science, there seems to be an overemphasis on inquiry based learning. In fact, there is even a popular figure that seems to assign the lowest impact on lectures and reading:

Figure downloaded from
The above figure was downloaded from a web page maintained by the World Bank. There are other versions. Daniel Willingham talks about the above pyramid in one of his articles, "Cone of learning or cone of shame":
If you enter "cone of experience" in Google scholar the first page offers a few papers that critique the idea, e.g., this one and this one, but you'll also see papers that cite it as if it's reliable.

It's not.

So many variables affect memory retrieval, that you can't assign specific percentages of recall without specifying many more of them:

  • what material is recalled (gazing out the window of a car is an audiovisual experience just like watching an action movie, but your memory for these two audiovisual experiences will not be equivalent)
  • the age of the subjects
  • the delay between study and test (obviously, the percent recalled usually drops with delay)
  • what were subjects instructed to do as they read, demonstrated, taught, etc. (you can boost memory considerably for a reading task by asking subjects to summarize as they read)
  • how was memory tested (percent recalled is almost always much higher for recognition tests than recall).
  • what subjects know about the to-be-remembered material (if you already know something about the subject, memory will be much better.
One of the papers that Willingham cites which criticizes the learning pyramid is Lalley, James P.; Miller, Robert H., "The Learning Pyramid: Does It Point Teachers in the Right Direction?", Education, v128 n1 p64-79 Fall 2007, which has the following abstract:
This paper raises serious questions about the reliability of the learning pyramid as a guide to retention among students. The pyramid suggests that certain teaching methods are connected with a corresponding hierarchy of student retention. No specific credible research was uncovered to support the pyramid, which is loosely associated with the theory proposed by the well-respected researcher, Edgar Dale. Dale is credited with creating the Cone of Experience in 1946. The Cone was designed to represent the importance of altering teaching methods in relation to student background knowledge: it suggests a continuum of methods not a hierarchy. While no credible research was uncovered to support the pyramid, clear research on retention was discovered regarding the importance of each of the pyramid levels: each of the methods identified by the pyramid resulted in retention, with none being consistently superior to the others and all being effective in certain contexts. A key conclusion from the literature reviewed rests with the critical importance of the teacher as a knowledgeable decision maker for choosing instructional methods.
Education is also business so both teachers and parents are frequently bombarded with "novel" approaches and learning resources that are supposedly based on research and evidence. More often than that, these are really unsubstantiated claims. What makes spotting bogus research tricky is our desire to find a silver bullet that will solve all problems in education. What prevents us from thinking critically is usually a prejudice we already have. We hate teachers. We hate lectures. So all of these must be ineffective in learning. The above pyramid simply confirms these prejudices so the pyramid is accepted without critical thinking. For example, here is a statement that can be found in a presentation on 21st Century Education given by a dean of education in the Philippines, who is also a member of the Technical Panel for Teacher Education of the Commission on Higher Education:
The 21st century educator takes risks and is prepared to tap into students’ knowledge of technology. With a vision of what he or she wants and what the technology can achieve, he or she can identify the goals and facilitate the learning. Educators can have students teach each other. The learning pyramid shows that the highest retention of knowledge comes from teaching others.
When one is absorbed in sound bites such as "discovery-based learning", "critical thinking", "learner-centered", and "peer and group learning", the pyramid is certainly quite attractive. Unfortunately, the fact that the learning pyramid is accepted by so many only illustrates a lack of critical thinking and complete disregard of the learner.

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