Numerous studies have investigated the behavioral effects of lack of sleep. However, most have looked at the impact of a total lack of sleep, rather than slightly reduced sleep over a more extended period.
To test the impact of partial sleep deprivation on emotional reactions, the researchers behind this study asked 42 people to change their sleep patterns for 2 weeks.
During the 2-weeks, participants had 5 consecutive nights of normal sleep followed by 5 consecutive nights of restricted sleep in which they could sleep no more than 5 hours per night. In the sleep-restricted phase, participants went to bed at approximately 2 am and woke up at about 7 am.
The researchers switched the order of the sleep patterns between the participants, with a two-day ‘wash out’ period in-between to allow people to reset before the next period.
The morning after each 5-day period, the researchers asked the participants to rate images on a nine-item scale of emotions.
The researchers took the images from the International Affective Picture System (IAPS), a database of pictures that psychologists use to study emotion and attention. The database contains a vast, wide-ranging selection of images that depict pleasant, neutral, and unpleasant events.
The researchers randomized the order of the pictures and assessed the emotion the image evoked, as well as the intensity of the emotion.
