As a rule, human beings are unreliable narrators. We assess and recall experiences through layers of overlapping biases that are hard to shake, even when we acknowledge that we see the world through tinted lenses. But certain situations (or qualities) amplify the slant of our perspectives. Case in point: Insomniacs are notoriously bad at assessing their sleep. The rest-challenged often believe they get less sleep, and take longer to fall asleep, than they actually do. In past research, discrepancies have repeatedly emerged between what people say about their rest and what objective sleep tests say.
Their un-truths aren't just a barrier to accurate science. Some researchers posit that misperceptions of sleep contribute to the development and persistence of sleep problems. By believing they don't sleep, people fuel anxiety about the issue, which, in conjunction with increased arousal and emotional upset, actually does interfere with their sleep. It's a fun cycle. Additionally, researchers have found that people who believe they can't sleep try to get rid of their sleep-related anxiety through irrational and counterproductive "safety behaviors," such as hanging out in bed longer than they should, drinking themselves drowsy and putting off other obligations to take naps. These sorts of attempts to solve their sleep woes only make things worse by disrupting sleep-and-wake rhythms.
Researchers have struggled to understand why insomniacs can't be trusted to kvetch about their sleeplessness without stretching the truth. Thanks to science, a number of unlikely explanations have faded from view. For example, it doesn't appear that insomniacs exaggerate their shuteye deficits because they generally can't gauge time. Outside the sleep arena, studies have found, insomniacs are as good as anyone at estimating how much time has passed.
In one new study, published in the Journal of Behavior Therapy and Experimental Psychiatry, researchers from the University of Leuven in Belgium attempted to make sense of the phenomenon by distinguishing between misperceptions of a single night's rest and of longer stretches of sleep. When people inaccurately assess how much sleep they got last night (and last night only), researchers blame a heightened state of arousal at bedtime. When people look back on a longer time period (i.e., a week or more) and exaggerate their state of unrest, researchers believe the issue lies in a tendency to overgeneralize negative experiences.
To test and flesh out their ideas, researchers recruited 54 adults (mostly young-ish, mostly female) for seven days of Zzz scrutiny. Before starting the trial, participants took assessments of depression, general sleep habits, overgeneralization and pre-sleep arousal. Overgeneralization describes a "tendency to generalize the experience of a single failure to all or many of life's experiences." Someone who thinks they're a has-been after screwing up one interview, for example, would fit the bill. Sleep arousal has to do with thought patterns, feelings and physiological states at bedtime. Signs of arousal include panic over falling asleep and a hastened heartbeat.
Then, for one week, participants kept sleep diaries and wore actigraphy bracelets. These two methods of measuring sleep let researchers compare subjective and objective reports of shuteye on a night-to-night basis.
After the trial ended, participants evaluated how they'd slept during the week-long experiment. This "global evaluation" let researchers see how participants' zoomed-out retrospective analyses compared both to actigraphy data and daily diary entries.
To evaluate misperceptions, researchers focused on two areas where insomniacs commonly make mistakes: how long they sleep (called Total Sleep Time, or TST) and how long it takes them to fall asleep (called Sleep Onset Latency, or SOL). Typically, people underestimate TST and overestimate SOL. In other words, they think that falling asleep takes forever and that sleeping hardly lasts.
Broadly speaking, researchers' predictions bore out. In terms of daily assessments, researchers linked differences between diary reports and actigraphy data to levels of cognitive arousal. So, participants' whose sleep diaries most differed from their bracelets' tattle-telling showed a tendency to get amped and anxious upon saying goodnight. They floated an interesting explanation for this finding: "Arousal disrupts the internal biological pacemaker used to perceive duration of time."
And, participants whose "global evaluations" contradicted the actigraphy data were more likely to have a problem with overgeneralization. In this context, over-generalizers tended to build up their nocturnal strife — turning a night or two of bad sleep into never, ever getting shuteye — and downplay their snoozing victories. And, these participants weren't necessarily the same ones whose diaries fell short of truthful, suggesting different underlying causes for single-night and longer-term sleep misperceptions.
The study had limitations. It's possible (but not certain) that the act of keeping a sleep diary increased the accuracy of global evaluations. Also, actigraphy bracelets aren't perfect measures of sleep, as they can confuse inactive but wakeful rest for sleeping, and restless sleep for being awake. And, as is often the case, causality is dicey. Arousal or overgeneralization might precede exaggerated accounts of poor sleep. Or, misperceptions of no-sleep nights might lead people to believe they turn into basket cases at witching hour. This idea stems from evidence that experiencing time as faster or slower can affect assumptions about mood-states, i.e., "that date went by in a flash, so I guess I had a blast," or "mass feels as long as a flight to China, so I guess I hate church."
And, the study findings did differ in some ways from what researchers predicted. Overgeneralization, for example, was only linked to misperceptions of total sleep time for participants on the lower end of the insomnia spectrum, an outcome that confused researchers. Which is to say, the study answers questions only to pose new ones. As usual, the answer is more research.