Insomniacs can't sleep because they can't stop thinking about sleep.
This cruel little catch-22 comes up in many a sleep study. And even when insomniacs aren't tossing and turning at night, their tortured relationship with rest affects how they perceive and interact with the outside world during the other 16 hours of the day. Yup, I'm talking about unconscious biases.
The can't-sleep disease, for instance, has been linked to a negativity bias. This means that an insomniac might see a neutral resting face and think: That scowling jerk wants to fight me. Insomniacs also seem to have "attentional biases for relevant-disorder stimuli." In other words, they pay disproportionate attention to sleep-related sights and sounds, such as a snoring subway rider, a bottle of Tylenol PM in the medicine cabinet, or a facebook ad for a mattress.
The precise nature of this bias is up for debate. Some research says insomniacs notice sleep-stuff faster than their better-rested peers. But a new study, published in the journal Behavior Research and Therapy, suggests that, while insomniacs and normal sleepers might notice sleep-related images at a similar speed, insomniacs fixate on the images for a longer period of time. If they see a bed, they keep staring.
Their fixation on all-things-sleep is thought to play a role in perpetuating their insomnia.
The insomniac's attentional bias isn't merely an interesting research tidbit. Their fixation on all-things-sleep is thought to play a role in perpetuating their insomnia. The precise relationship between the two factors isn't clear. But it's possible that sleep-related stimuli put insomniacs into a state of arousal — and arousal and bedtime don't mix well.
There's evidence from previous studies that insomniacs process sleep-related stimuli faster than normal sleepers. So, according to this idea, if there's a sleep clinic ad in a subway car, and an insomniac and non-insomniac enter the car at the same time, the former would notice the ad first. But these studies analyzed attentional bias using computerized tests, such as the classic Stroop test. This is important because insomniacs were reacting to sleep-related words in an artificial context.
For the current study, psychologists and sleep-and-circadian researchers from the UK wanted to see if insomniacs would exhibit a similar bias towards sleep-related visuals in a real-world situation. Basically, they sought to answer the question: Do insomniacs focus on sleep-related images in an atypical way when they're scrolling through their news feeds, or casually enjoying a milkshake, or otherwise going about their days?
Researchers devised an experiment that would let them test attentional bias in a more natural setting: They used eye-movement-tracking software to pinpoint differences in the way insomniacs and normal sleepers surveyed real photos of bedrooms, living rooms, and kitchens. (Eye-tracking is a more direct measure of attentional bias than methods used in previous studies.)
It's possible that sleep-related stimuli put insomniacs into a state of arousal — and arousal and bedtime don't mix well.
Specifically, they were looking to see if insomniacs would pay more attention to beds (the sleep-related stimuli in this study) than other objects in photos. They measured attention in several ways, including the speed with which participants fixed their gazes on beds, the length of time they spent staring at beds, and the number of times they re-shifted their focus back onto beds after looking at other objects.
While the results did reveal an attentional bias, it wasn't the same one that emerged in previous studies. Insomniacs didn't start paying attention to beds any faster than the other group. But, once they looked at a bed, they kept on looking. Compared to normal sleepers, insomniacs remained fixated on beds for significantly longer periods of time and glanced back at them more frequently. Insomniacs also lingered on sofas and desks in a similar manner. This could mean, researchers surmised, that these objects were seen as potential places for rest.
This study supports the general notion that insomniacs have some type of bias towards sleep-related stimuli. But there are plenty of unknowns to fill in. The next step in understanding insomniacs' unconscious tendency to gawk at beds, researchers wrote, is figuring out how this type of bias helps people become, and remain, insomniacs.