More evidence that sleep improves memory

26 Aug

From the journal Psychological Science:

“Both repeated practice and sleep improve long-term retention of information. The assumed common mechanism underlying these effects is memory reactivation, either on-line and effortful or off-line and effortless. In the study reported here, we investigated whether sleep-dependent memory consolidation could help to save practice time during relearning. During two sessions occurring 12 hr apart, 40 participants practiced foreign vocabulary until they reached a perfect level of performance. Half of them learned in the morning and relearned in the evening of a single day. The other half learned in the evening of one day, slept, and then relearned in the morning of the next day. Their retention was assessed 1 week later and 6 months later. We found that interleaving sleep between learning sessions not only reduced the amount of practice needed by half but also ensured much better long-term retention. Sleeping after learning is definitely a good strategy, but sleeping between two learning sessions is a better strategy.”

 

 

The ideal professor

24 Aug

Here’s a paper, just published in Personality and Individual Differences, that explores students’ concepts of the ideal professor.

From the abstract:

Despite intuitions that the ideal teacher has a particular set of non-cognitive characteristics, there is little research investigating such issues. The current two studies investigate students’ descriptions of “ideal” instructor personality using the Five-Factor Model of personality. Both absolute personality preferences (certain traits are universally desired) and relative personality preferences (certain traits are desired relative to students’ own level of the trait) are examined among 137 first year mathematics students (Study 1) and 378 first year psychology students (Study 2). Students provided Big Five personality ratings for themselves, their actual instructor, and their ideal instructor. Supporting the absolute preference hypothesis, students rated their ideal instructor as having significantly higher levels than both themselves and the general population on all five personality domains (except for openness in Study 1), with particularly large effect sizes for emotional stability and conscientiousness. Supporting the relative preference hypothesis, students also rated their ideal instructor as having a similar Big Five profile to themselves.

As someone who teaches at the university level I found this quite interesting. In Piaget’s theory of development, teenagers and adults are in the formal operations stage. Piaget describes a kind of formal operations ego-centrism, where the individual compares abstract notions of perfection with reality and finds reality wanting. For example, adolescents will construct a notion of what perfect parents would be like, and then compare their real parents with the abstraction. Any guesses on how the real parents come out in this comparison?

So it seems that our students have ideas about the perfect instructor and we actual teachers suffer by comparison.

Does having an instructor who matches your ideal help your performance? Here is what this study found:

if their actual instructor’s personality was similar to their ideal instructor’s personality, students showed greater educational satisfaction (but not higher performance self-efficacy nor academic achievement).

 

Why is the full moon myth so powerful?

22 Aug

I was reading this paper in the journal Teaching Psychology about how evidence can help dispel common myths about human behavior, when I came across this sentence:

“In the second case, the superstition that a full moon increases erratic behavior remained impervious to change. Unfortunately, students maintained a strong belief in lunar lunacy at the beginning of the course, and the belief did not change at the end of the course.”

It conforms to my experience, many students at all levels, including doctoral students, are absolutely convinced of the influence of the full moon on human behavior. Students have actually gotten angry when I point out the contrary evidence.

In their paper, McCarthy and Frantz offer a possible explanation:

“We believe this particular misperception is especially difficult to change because people continually employ confirmation bias as a way to retain their belief.”

I suspect that cultural factors might also be involved. I remember in one class two Asian students were astonished by the debate. They had never heard anyone suggest the full moon as a harbinger of bad tidings. In their respective cultures the full moon is seen as an auspicious omen.

 

Olympic athletes use transcranial direct current stimulation

19 Aug

According to IEEE Spectrum:

“A handful of athletes competing at the Summer Olympic Games in Rio next week will arrive having tried to boost their performance using an unconventional (and not-yet-banned) technology: brain stimulation. The technique, called transcranial direct current stimulation (tDCS), involves channeling a tiny current through specific regions of the brain, making neurons in that area more likely to fire.”

The athletes are using the Halo tDCS device. Here is the promotional video:

Before you run out and buy one of these devices, I suggest you read “An open letter concerning do-it-yourself users of transcranial direct current stimulation” published in The Annals of Neurology.

 

Evidence for hypnosis

17 Aug

Hypnosis is a fascinating subject. For years a debate has raged among psychologists over its reality. For many years the dominant view has been that hypnosis is not some special state of consciousness, but, actually, a social phenomenon where an individual simply conforms to the authority of the hypnotist because of prior beliefs about how a hypnotized person is supposed to behave.

Recently, however, the idea of hypnosis has an altered state of consciousness has re-emerged. This is because of studies showing physiological correlates of hypnosis. Here is the abstract of a recent paper published in the journal Cerebral Cortex:

“Hypnosis has proven clinical utility, yet changes in brain activity underlying the hypnotic state have not yet been fully identified. Previous research suggests that hypnosis is associated with decreased default mode network (DMN) activity and that high hypnotizability is associated with greater functional connectivity between the executive control network (ECN) and the salience network (SN). We used functional magnetic resonance imaging to investigate activity and functional connectivity among these three networks in hypnosis. We selected 57 of 545 healthy subjects with very high or low hypnotizability using two hypnotizability scales. All subjects underwent four conditions in the scanner: rest, memory retrieval, and two different hypnosis experiences guided by standard pre-recorded instructions in counterbalanced order. Seeds for the ECN, SN, and DMN were left and right dorsolateral prefrontal cortex, dorsal anterior cingulate cortex (dACC), and posterior cingulate cortex (PCC), respectively. During hypnosis there was reduced activity in the dACC, increased functional connectivity between the dorsolateral prefrontal cortex (DLPFC;ECN) and the insula in the SN, and reduced connectivity between the ECN (DLPFC) and the DMN (PCC). These changes in neural activity underlie the focused attention, enhanced somatic and emotional control, and lack of self-consciousness that characterizes hypnosis.”

(Hat tip to Brain Blogger)

A review of my memory improvement book!

16 Aug

I just came across this review of my book. Many thanks to The Art of Memory.

There is also a lengthy summary in the comments.

Brain training increases grey matter volume

15 Aug

On Friday, I reported on a meta-analysis that presented evidence that working memory brain training does not transfer to other cognitive skills. The most recent issue of Personality and Individual Differences carries a paper titled:  “Gray matter volumetric changes with a challenging adaptive cognitive training program based on the dual n-back task.” The n-back task is the most widely used procedure for working memory training in academic research.

Surprisingly, these results do not, necessarily, contradict each other. As noted in the abstract:

“Changes in the gray matter volume of these clusters were correlated with a) behavioral changes across the training program and b) changes in four psychological factors assessed before and after training (fluid and crystallized intelligence, working memory capacity, and attention control). None of these correlations were statistically significant, and therefore, psychological and biological changes were seen as independent.”

Since there working memory training does improve performance on the trained task, we would expect there to be some kind of measurable physical change in the brain. But this does not mean that the training effects are transferable to other cognitive domains.

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