Believe you have slept well: the power of ‘placebo sleep’

‘Placebo sleep’, or believing you have slept well, even if you haven’t, could be another way the placebo effect is demonstrated in our lives.

placebo sleepA recent study suggests that it might not be how much sleep you have, but your thoughts about your sleep that guarantee how rested you feel and how well your brain works. 


In this study by researcher Eric Horowitz, he and his colleague first  gave participants a short lecture about how getting more and better sleep improves cognitive function.

They also told them that during the normal person’s night of sleep, about 20 to 25 percent of it is REM sleep, the kind that helps the brain most. The researchers then attached sensors to the subjects and told them the sensors would measure pulse, heart rate and REM while the subjects slept. (This was a lie.) Some of the subjects were later told that they got 16.2 percent REM sleep, while the others were told they got 28.7 percent REM sleep. (This was also a lie.)

What happened was  those who were told they got better sleep, did better on a test of information processing speed called the Paced Auditory Serial Addition Test (PASAT), which involves adding many numbers together, as well as on a verbal fluency test called the Controlled Oral Word Association Task (COWAT). Those who were told they got a poor  sleep did worse. The same relationship didn’t hold for self-reported sleep quality–those who thought they got better sleep didn’t generally do better on the PASAT than those who thought they hadn’t had a good night’s sleep.

The paper states: ‘These findings supported the hypothesis that mindset can influence cognitive states in both positive and negative directions, suggesting a means of controlling one’s health and cognition.’

What’s your experience of sleeping? Are you a good sleeper or a poor sleeper? How could you test changing your mindset about sleep to see whether the ‘placebo sleep’ has any effect?


Discover more:

‘Placebo sleep affects cognitive functioning’ (2014) –  Journal of Experimental Psychology:  Learning, Memory and Cognition

Just thinking you had a good night’s sleep... – The Independent