What Happens To Our Brain When We Use Spaced Practice?

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What happens to learners when use spaced practice in our classroom?

This piece of research unpicks the impact of spaced practice. First published in 2010, Callan and Schweighofer write that “Despite over a century of research, the psychological and neural basis of [the] spacing effect is still under investigation.”

A decade later, where are we now and how is ‘spacing’ influencing what teachers can do in the classroom?

The research

I thought it would be worth blogging a summary about this paper for teachers to compare what this research recommends to enable teachers to evaluate where we are today with our understanding of spaced practice as an effective teaching strategy.

The research design “consisted of an English vocabulary pre-test taken outside and inside an MRI scanner” and another “distracter task inside the scanner, and two post-tests outside the scanner.”

Participants were given a list of 150 words that could potentially be used in the study. The testing occurred after 10 minutes and again after one day.

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The Spacing Effect in Semantic Encoding (2010)

In this “vocabulary learning experiment… each composed of a known word paired with a novel word” were evaluated and presented in both spaced and massed conditions.

The study investigated semantic encoding of verbal information. In plain English, determining what a word means as opposed to the sound or what it looks like. Semantic memory – remembering concepts, rules and facts – and in this case, associating the meaning of a word in order to store the information better.

The research design set out to “explore the neural basis of the spacing effect”. What happens in our neurons when we are exposed to, for example, words over a spaced period of time.

You can read more about the methodology on page 647 of the journal/page 3 of the PDF.

To evaluate encoding using the spacing effect, stimulus was provided as a pair; a “known word to a novel phonological sequence.” The control condition ensure there was no pairing to be encoded know any encoded-related spacing effect.

The words used were common monosyllabic nouns composed of four or five letters. The phonological sequences were generated to control structure and word length.


Recall tests suggested that (n= 13) subjects performed significantly better for spaced over massed conditions.

Participants reported using both verbal rehearsal and elaborative rehearsal strategies for encoding in both conditions. Interestingly, there was no significant differences between native and non-native speakers.

Analysis of participants brain activity during encoding revealed a greater performance‐related increased activity in the spaced relative to massed condition.

As I explore parts of the brain in my own research, “the left frontal operculum [is] known to be involved in encoding via verbal maintenance rehearsal.” A ‘little lid’ (Latin translation) for covering our insular cortex; this is the part of the brain that we believe is involved in our consciousness, emotions and are internal, physical and chemical condition.

Neural Correlates of the Spacing Effect in Explicit Verbal Semantic Encoding Support the Deficient-Processing TheoryDaniel E. Callan and Nicolas Schweighofer
The Spacing Effect in Semantic Encoding (2010)

I’m definitely not a neuroscientist, but from what I can decipher, this fascinating graphic demonstrates what neural activity happens in our brains when we are exposed to spaced and massed testing. The brain image is a sagital slice (divided into left and right) to show frontal operculum activity.

The research results suggest that the spacing effect does something to the neurons in our brain! In this case, activity in the frontal operculum. Trying to keep this as simple as possible for my own benefit as well as people reading this, participant encoding increased their verbal rehearsal and strengthened the phonological and word-level information. Put simply, it was transferred into long-term memory.

What should teachers do?

  1. If this research testing was conducted after 10 minute and one day intervals, this is something that could be translated into every classroom.
  2. In the part of the brain responsible for developing our verbal acquisition, what can all teachers do more of to strengthen subject terminology? Only today, I conducted quality assurance with a modern foreign languages middle leader and I highlighted how effective MFL teachers are at oral recital, speaking and listening tasks and routines to help students learn language.
  3. When teaching vocabulary, there is a greater need to re-encode items in a spaced situation. We know this will draw on our working memory reserves, so there is much to be thought through here…

This explicit phonological-to-semantic research demonstrates the impact of spacing. If we present verbal information in a spaced manner, it improves our recall performance.

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