You don't need science to tell you that people feel better after a good night's sleep than they do on those grouchy days following a night of tossing and turning. But in looking at the specifics of how those positive feelings manifest, researchers, you may be thankful to know, have found something interesting.
Previous studies have shown that feeling grateful helps you to sleep better. In one such study, people who wrote in a "gratitude journal" for 15 minutes at night were found to not only have less on their mind at bedtime, it also improved the duration and quality of their sleep.
Now, new research says the connection between gratitude and sleep seems to also work the other way.
"Our research looks at the link in the other direction and, to our knowledge, is the first to show that everyday experiences of poor sleep are negatively associated with gratitude towards others," Amie Gordon, a doctoral candidate at the University of California, Berkeley, said in a release.
In other words, if you don't sleep well, chances are you don't feel grateful for the things in your life, including your spouse.
Gordon and Serena Chen, a psychology professor at Berkeley, examined the link between sleep quality and gratitude in three studies.
In the first, people who got a good night's sleep were more grateful after listing five things in life that they appreciated, compared to people who did not sleep well the night before.
In another study, students recorded their feelings of gratitude and their sleep every day for two weeks. On the days following a poor night's sleep, there was a corresponding decrease in feelings of gratitude.
In the third and final study, which looked at heterosexual couples, people were found to feel less grateful toward their significant others if they don't usually sleep well or if their partners don't.
"In line with this finding, people reported feeling less appreciated by their partners if they or their partner tends to sleep poorly, suggesting that the lack of gratitude is transmitted to the partner," Gordon said. "Poor sleep is not just experienced in isolation. Instead, it influences our interactions with others, such as our ability to be grateful, a vital social emotion."