Two groups of young adults in Lyon learned the same 16 Swahili words. One group sat down at 9 in the morning, the other at 9 at night. Twelve hours later, each group came back and practiced the words again until they had all 16.
If you had to bet on one of them, you'd probably pick the morning group. Most learners would. Mornings are when we feel sharp, and plenty of us have stopped reading Spanish at night because whatever we read before bed seems half gone by breakfast.
The evening group won, by a lot.
Two sessions, twelve hours apart
The study was run by a team led by Stéphanie Mazza and published in Psychological Science in 2016. Forty people took part, half in each group, and everyone practiced in the first session until they had all 16 words.
Everyone got the same words and the same twelve hours between sessions. The one difference was whether a night's sleep sat in the middle.
The people who had slept came back remembering more of the words (about 10 of the 16, against fewer than 8 for the daytime group), and they needed about half as many rounds to get all 16 back. A week later they still knew 15 of them on average. The daytime group knew 11. Six months later, the sleepers knew more than twice as many.
The night needed the second read
The researchers also ran a third group. These people learned in the evening and slept, but in the morning they only got one quick try at the list, with no proper second session.
A week later they did no better than the daytime group.
What helped was the pair: a night's sleep, and then a real second go at the words the next morning. In the study, that morning session after the night was the one that paid off.
In an earlier letter I suggested reading a story once and then again the next day, so the second read has room for the Spanish. This is one more reason to do it, and a reason to put a night between the two.
A story about turning off the light
There's a story in my Health and Wellness book for intermediate learners about Luciano, a graphic designer in Montevideo who has finished his workday past eleven at night for fifteen years. After a serious talk with his doctor, he starts shutting the laptop at nine and putting it away in a drawer. A las diez y media, en la cama, con un libro de papel. At half past ten, in bed, with a paper book.
It takes him almost four months to stop thinking of rest as laziness. By the end of the story he sees it as the time when el cuerpo y el cerebro se ponían a trabajar en otra cosa, en silencio, sin que él lo supiera. The body and the brain set to work on something else, in silence, without him knowing.
Luciano means rest in general. The study tested word lists rather than stories, but for the Spanish you read just before bed, it points the same way.
A small experiment for this week
You can run a small version of the study on your own reading. Pick two short stories at the same comfortable level, from a book you already have or from the catalog.
Read the first one at lunch, all the way through, and underline any word you stop on. Read it again at dinner, and write down how many of the underlined words read easily this time, out of how many you marked (6 of 9, say).
Read the second one in bed, as the last Spanish of your day, underlining the same way. Read it again the next morning, before you look at your phone, and write down the same two numbers.
Then put the lunch-to-dinner score next to the bedtime-to-morning one.
¡Sigue adelante!
Ariel