If you feel unappreciated in your relationship, it may have something to do with your partner not getting enough sleep, according to a new study.
Those who sleep badly at night or experience sleep deprivation show less appreciation for their partner, found researchers from the University of California, Berkeley.
The study looked into how sleep habits impact gratitude and found that sleep deprivation can leave couples "too tired to say thanks" and can make one or the other partner feel 'taken for granted'.
"Poor sleep may make us more selfish as we prioritise our own needs over our partner's," said Amie Gordon, a UC Berkeley psychologist and lead investigator of the study in a statement.
The results shed new light on the emotional interdependence of sleep partners, offering compelling evidence that a bad night's sleep leaves people less attuned to their partner's moods and sensitivities.
For many couples, nighttime can turn into a battleground due to loud snoring, sheet-tugging or one partner tapping on a laptop while the other tosses and turns.
"You may have slept like a baby, but if your partner didn't, you'll probably both end up grouchy," Gordon said.
Gordon noted that many people claim to be too busy to sleep, even priding themselves on how few hours of slumber they can get by on.
The observation inspired her, in part, to study how a lack of sleep might be affecting love lives.
More than 60 couples, with ages ranging from 18 to 56, participated in each of Gordon's studies. In one experiment, participants kept a diary of their sleep patterns and how a good or bad night's rest affected their appreciation of their significant other.
In another experiment, they were videotaped engaged in problem-solving tasks. Those who had slept badly the night before showed less appreciation for their partner.
Overall, the results showed poor sleepers had a harder time counting their blessings and valuing their partners.
The findings were presented at the annual meeting of the Society for Personality and Social Psychologists in New Orleans.