HM works from his iPAD. This is the print title of an article by Simon Makin in the October 1 issue of the New Scientist. The healthy memory blog has stressed the importance of the unconscious mind and provided suggestions as to how to make use of your unconscious mind. This and the following blog posts taken from this issue of the New Scientist elaborate on these ideas. This first post reviews a study done in 1999. A team at the University of Libek in Germany put 15 volunteers to bed at midnight. The team either told the participants they would wake them at 9 am and did, or told them they would wake them at 9 am, but actually woke them at 6 am, or said they would wake them at 6 am and did.
The last group had a measurable rise in the stress hormone adrenocorticotropin from 4:30 am, that peaked around 6 am, when these participants were told they would be awakened. The participants woken unexpectedly at 6 am had no such peak. The researchers concluded that the unconscious mind can not only keep track of time while we sleep, but also set a biological alarm to jump-start the king process.
A 2014 study by Sid Koulder of the Ecole Normale Superireure in Paris and his colleagues found that the sleeping brain can also process language. They trained participants to push a button with their left or right hand to indicate whether they heard the name of an animal or object as they fell asleep. They monitored the brain’s electrical activity during training and when the participants heard the same words when asleep. Activity continued in the brain’s motor regions even when asleep, indicating that the sleepers were preparing to push the correct button. The participants could also correctly categorize new words first heard after they had dropped off to sleep, indicating that they were genuinely analyzing the meaning of the words while asleep.
A more recent study found that while language processing continues in REM sleep for words heard just before bed, once in deep sleep all responses disappear as the brain goes “offline” to allow the day’s memories to be processed. Boulder says that “your cognition about things in the environment declines progressively towards deep sleep. Sleep is not all-or-none in terms of cognition, it’s all-or-none in terms of consciousness.”