Couples do pretty well at picking up one another's more intense feelings, like happiness or anger, but they are not as sensitive to "soft negative" emotions, said the study published in the journal Family Process.
‘While couples pick up each other's intense feelings, like happiness or anger with ease, they find it hard to pick up feelings of sadness or loneliness.’
"We found that when it comes to the normal ebb and flow of daily emotions, couples aren't picking up on those occasional changes in 'soft negative' emotions like sadness or feeling down," said study lead author Chrystyna Kouros, Associate Professor at Southern Methodist University, Dallas, US.
The researchers believe that even when a negative mood is not related to the relationship, it ultimately can be harmful to a couple.
"Failing to pick up on negative feelings one or two days is not a big deal," Kouros said.
"But if this accumulates, then down the road it could become a problem for the relationship. It's these missed opportunities to be offering support or talking it out that can compound over time to negatively affect a relationship," she added.
For the study, over 100 participants completed daily diaries about their mood and the mood of their partners for seven consecutive nights.
The problem is not one for which couples need to seek therapy, Kouros said.
Instead, she advises couples to stop assuming they know what their partner is feeling.
"I suggest couples put a little more effort into paying attention to their partner -- be more mindful and in the moment when you are with your partner," she said.
She cautions, however, against becoming annoying by constantly asking how the other is feeling, or if something is wrong.