Self-explanation helps learning

A meta-analysis by Bisra and colleagues, from Simon Fraser University in Canada, shows that prompting students to elaborate on learning material and form conceptual links (self-explain) is a significant boost to learning outcomes.

The authors found that self-explanation has strong effects across almost all learning materials (e.g. problem solving, worked examples), learning types (e.g. conceptual, procedural), and learning topics (e.g. maths, science, social science). Furthermore, their analysis showed that time spent self-explaining is more effective than time spent studying otherwise (for example re-studying or practising problems). Self-explanation was even more effective than providing students with written out explanations. The study suggests that teachers should, wherever possible, prompt students to engage in self-explanations to improve their learning outcomes.

Bisra et al. (2018) Inducing self-explanation: a meta-analysis. Educational Psychology Review DOI: https://doi.org/10.1007/s10648-018-9434-x

Attention! Improving memory by quietening brain activity

An attentive classroom is often a quiet classroom, in which any single voice is easily heard above tranquil surrounds. In the brain, it seems the same – attention quietens brain activity in a memory-related brain region, helping signals stand out from the crowd.

Epilepsy patients implanted with electrodes were given a verbal memory task while their brain activity was measured. The researchers compared activity for remembered words that were preceded or not preceded by a visual cue; this cue triggered attention, letting the researchers distinguish attention-triggered memory from ‘accidental’ memory (words remembered even though they weren't cued). In the anterior temporal lobe, attention caused decreased high-frequency brain activity, decreased spike activity, and an increased signal-to-noise ratio. These changes were associated with better memory. The study shows that attention suppresses high frequency brain activity in the anterior temporal lobe to enhance verbal memory processing.

Wittig Jr. et al. (2018) Attention improves memory by suppressing spiking-neuron activity in the human anterior temporal lobe. Nature Neuroscience 21: 808-810 DOI: https://dx.doi.org/10.1038/s41593-018-0148-7

Intelligent brains are big and simple

After accounting for gender and age, brain size is a reasonable predictor of intelligence. Another predictor is how efficiently the brain operates, a feature that can be measured by looking at the brain’s metabolic activity during a task. Although these facts have been appreciated for some time, it hasn’t been clear how efficiency is actually achieved in the brain.

Researchers from Ruhr University Bochum have used a neuroimaging technique to show that efficiency – why intelligent people use less brain activity – is related to the density and complexity of the branches that extend from a neuron, with higher intelligence associated with less dense and complex branching. The finding fits with the well-established ‘pruning hypothesis’, in which synapses are created in excess and then pruned away for more efficient communication.

Genҫ et al. (2018) Diffusion of markers of dendritic density and arborisation in gray matter predict differences in intelligence. Nature Communications DOI: https://dx.doi.org/10.1038/s41467-018-04268-8

Sleep spindles aid memory consolidation

As we sleep, our brain activity cycles through stages distinguishable based on the frequency of oscillations, or brain waves. During one of these stages (stage 3, slow-wave sleep), characteristic patterns called spindle oscillations occur. Antony and colleagues from Princeton University designed an experiment in which participants associated sounds with the location of an image on a grid. After studying these associations, they took a nap. During the nap, some of the sounds were played during slow-wave sleep to cue memory recall. The researchers found that this sound cue improved performance on the post-nap test, a result that has been shown before. More interestingly, the study also found that the timing of cues relative to sleep spindles affected post-nap memory performance, providing evidence that spindle oscillations are important for consolidating recently learned material.

Antony et al. (2018) Sleep spindle refractoriness segregates periods of memory reactivation. Current Biology 28(11): 1736-1743.e4 DOI: https://doi.org/10.1016/j.cub.2018.04.020