To attain the highest levels of knowledge, does one really have to start from the bottom?

In a recent study published in the Journal of Education Psychology, cognitive scientist Pooja K. Agarwal showed that in two laboratory experiments and one classroom experiment with 6^th grade students, those who had only practised answering complex questions that included the application of knowledge, or a mixture of complex questions with simple, factual questions achieved better results in a final test with complex questions than those who had only practised answering factual questions. These results indicate that students can benefit from complex questions (or those requiring high levels of processing), and master the materials studied at the highest level, while building more basic knowledge that allows them to answer simple questions.

This idea that in order to acquire an outstanding command of knowledge, students do not necessarily have to start by building their knowledge through simple, separate memorisation processes and then gain a basic understanding of the facts, but rather that they can start by practising more complex activities, is a provocative idea. It goes against the prevailing notion that teachers should always teach basic notions and activities first and separately, so that they can then teach, for example, critical thinking ^[1]. However, this is not a completely new idea, and several educators have already suggested that adopting activities that promote critical thinking can benefit learning rather than spending most of the class time teaching basic facts ^[2]. However, it is important to clarify that these educators do not mean that students need not obtain basic factual knowledge, but rather that, by developing more complex activities, they are able to acquire and consolidate this basic knowledge, and also improve their performance in tasks that require knowledge and processing at a higher level.

Bloom’s Taxonomy: A mere hierarchy or a necessary sequence of learning steps?

Published in 1956, Bloom's Taxonomy proposed an organisation of cognitive processes, from the simplest to the most complex ones. For example, the original Bloom's Taxonomy included, from the simplest to the most complex, the following levels: knowledge, comprehension, application, analysis, synthesis, and evaluation. In 2001, Anderson et al. reviewed the original taxonomy and proposed that verbs be used to designate the different levels. Thus, the lower levels were renamed "remembering" and "understanding", and the higher levels "applying", "analysing", "evaluating", and "creating".

This distinction has been repeatedly interpreted as indicating that a student must first master the processes at lower levels, and only later can they practice the processes at higher levels. Certainly, in order to apply, analyse, evaluate, or create, pupils must know the facts. The question is whether study and practice should be separated into two distinct and sequential steps: first, understanding and practising basic knowledge, and only later, applying, analysing, evaluating, and creating.

Bloom's Taxonomy is usually represented by a pyramid, in which the lower levels represent the factual knowledge and basic skills, and the higher levels, the more complex knowledge and skills. This visual representation helps to suggest that the basic knowledge is the foundation of the most complex knowledge, and that students must master the lower levels before they can reach the capabilities depicted at the higher levels. Many educators rely on this order to programme the educational activities they provide for their students. Thus, in many classrooms, pupils begin by reading a school book in order to remember and understand facts (e.g. read about the stages of the scientific method), and only after spending time training their knowledge at this level do they perform activities which require the application of these facts (e.g. write a scientific report which illustrates the stages of the scientific method).

Despite the extensive use of Bloom's Taxonomy, the sequence from lowest to highest levels has not yet been studied in depth or defined. Agarwal has examined precisely whether, during teaching, educators can move directly into activities that require complex knowledge.

Skipping levels when using retrieval practice

Agarwal asked participants to read passages on social issues (e.g. social security support) and then gave them questionnaires with multiple choice questions. Some participants were asked questions about the facts presented that only required them to remember the answer, while other students were asked questions that required participants to apply, analyse, evaluate, or create a scenario based on the passage. In a final test, regardless of the type of questions received, participants who had practiced information retrieval performed better than participants who had not answered the questionnaires, demonstrating the well-known benefits of retrieval practice.

However, when students had answered to factual questions only, they performed better on factual final questions alone, but when they had answered to more complex questions they performed better on complex final questions, which measured more in-depth knowledge. Moreover, when students had practised retrieval with a mixture of the two types of questions (i.e. when they have answered both factual questions and complex questions whose content did not derive from the factual questions), they performed better in both the factual final questions and the complex final questions.

Agarwal obtained similar results in a different experiment with 6^th grade students, in a classroom, and with materials on History. In short, "building basic knowledge through retrieval practice has not increased high-level learning", says Agarwal. Instead, "retrieval practice involving high-level or mixed issues has increased high-level learning".

These effects indicate that using an effective learning strategy, such as retrieval practice, and practising at higher levels of the Bloom's Taxonomy can lead students to reach higher levels of the taxonomy more quickly. This means that assigning students to tasks that require critical thinking and the application and analysis of knowledge can lead them to learn faster (and more efficiently) to apply knowledge and think critically about the subjects studied. Specifically, practicing the retrieval of a mixture of basic knowledge and higher level thinking seems to provide the best results. This approach can benefit both students and teachers by saving class and study time and by keeping students more interested as they have access to more difficult and interesting activities earlier.

Implications for the classroom

Students seem to benefit from the practice involving complex questions and activities. But no one denies that students must also master the most basic knowledge and understand educational materials. So what do these results mean in terms of the teaching practice?

1. Retrieval practice improves learning. Provide your students with training questionnaires.

2. Retrieval activities do not need to be the mere retrieval of memorised information. Questionnaires in which students have to apply their knowledge, analyse facts, or think critically about what they know could be more beneficial than questionnaires in which students only have to remember facts.

3. Practice makes perfect (or almost). If you want your students to reach the highest levels of Bloom's Taxonomy, train them with activities that reflect those levels.

4. As we mentioned, factual knowledge is also important, and the results of the Agarwal study show that questionnaires that combine factual and complex questions seem to benefit learning the most. Provide your students with retrieval practice that involves a mixture of low and high level processes. This practice will also keep students with different levels of knowledge aware of the activities.