How effective is the human memory?
As an exercise, try the following with a partner; slowly read aloud the following words in order and then ask them to recall as many as they can:
Desk, Lamp, Bookcase, Table, Chair, Einstein, Wardrobe, Stool, Bed, Window, Door
If you repeat this with multiple volunteers, you’ll likely find that people tend to remember the beginning and the end words, along with anything that is noticeably unusual (e.g. the word ‘Einstein’). The rest is largely forgotten, being neither memorable nor positioned at the start (where words enter long term memory) or end (where words can be held in the short term/working memory) of a sequence. Known as the serial position effect (Murdock, 1962), an exercise such as this ably demonstrates the importance of memory in the classroom and reminds us that just because we may have taught the content of a particular topic, it doesn’t necessarily follow that anyone will have remembered or learnt the content.
Understanding the memory
What then, does research tell us about the workings of the human memory? This is a complex field of neuroscience research, but at a simple level we might consider three elements of the memory (Baddley and Hitch 1974):
- Sensory memory – containing our first impressions of incoming sensory information with around 250-500 milliseconds of storage
- Working memory – where the majority of ‘thinking’ and processing occurs with about 20 seconds of storage. Active rehearsal is needed in order to get the information processed and stored in the long term memory
- Long term memory – a constantly evolving, long term storage of information which can span days, years or even your whole life.
Working alongside these elements, we also have processes such as encoding (or registering), where information is converted to a form that can be stored. Our brains are multi-sensory and information on a given subject can be encoded by visual, auditory or sensory means which are often interconnected; for example, an image of a bell is visual but may trigger encoding through both visual and auditory means as the brain associates the image with a memory of the sound it makes. Complex interactions and connections between stored information and knowledge systems in the brain are known as schemata and help us interpret reality.
Retrieval (or remembering), where information stored in long term memory is recalled, is an important mechanism to consolidate information and secure it within the long term memory. Research has shown that regular and immediate rehearsal of learned information is more likely to result in encoding to the long term memory; for example if you were to be tested on your recall of the words in our earlier example immediately after exposure, you would do rather better than if you were not tested for several hours after. If you were repeatedly tested at regular intervals, you would find that the constant rehearsal and retrieval gradually improved your ability to remember all the words in the sequence. This is nothing new – Ebbinghaus’s forgetting curve was first proposed in 1885 but it is worth considering how these principles can be applied to teaching and their implications for learning.
Strategies for teaching
Various evidence based strategies that apply an understanding of memory to the classroom have been researched. Dunlosky’s Strengthening the Student Toolbox and the Learning Scientists are two such sources that provide useful insight into how various techniques can be applied to the classroom. Among some of the most effective are:
- Retrieval practice is the process of deliberately recalling stored memories (i.e. moving information from long-term memory to working memory), through the synchronous firing of associated neurons and neural networks. Practice and rehearsal of freshly-learnt knowledge causes information to become automatically accessible, freeing up the brain’s limited capacity to pay conscious attention and so be ready for further learning. The most obvious example of this is in the classroom is practice testing - the frequent administration of low-stake tests that revisit what has been previously learnt. Examples include the use of starter questions/quizzes, past paper questions, online quizzes (e.g. Socrative, Kahoot, Seneca) or asking students to create knowledge organisers
- Distributed/spaced practice involves having breaks between repeated content rather than massing those repetitions into a single blocked learning episode. Such practice may improve the long-term memory by increasing retrieval effort and therefore encoding to long term memory over time. Although there is no definitive rule on how long the breaks should be, Cepeda et al (2008) has provided evidence that suggests the lag should be around 10-20% of the retention interval – e.g. if a concept was taught at the start of year 9 and assessed at the end of year 11, it would be helpful to revisit the concept every four to eight months or so.
- Elaborative interrogation is when a learner tries to understand why something is true, rather than just recall the ‘raw’ facts. It can take the form of effective questioning or sharing ideas in the classroom. Such practice can help the students make connections between their knowledge, skills and understanding, i.e. creating new neural associations or adding to existing schemata. Applied to the classroom, this can take the form of questions that present conceptual challenges (e.g. Next Time Questions, Concept Cartoons and the BEST Evidence Science Teaching resources) or questions that make students ask questions (e.g. Fermi problems)
Taking it further
There are several other techniques including interleaving, concrete examples and dual coding that are worth considering. It is also worth observing teaching practice in your own school and asking questions such as:
- Which techniques or strategies are already being used?
- Is there a preference for some of these techniques but not others? Does this vary by subject or teacher and why?
- Which of these techniques are used by the most successful teachers and how are they applied to the classroom?
The field of cognitive neuroscience is a fascinating area and one which you can learn more about through courses such as The Science of Learning and Supporting Memory. By developing an understanding of how memory works, we are more able to support learners to retain and recall crucial knowledge, build their understanding and support them through the process of educational recovery.
Are there any techniques that work particularly well for you? How widespread are these techniques in your school and how effective are they? Are there any good resources that you use to help with retention and recall of knowledge? Let us know in the discussions in 11-19 Science.