Men, please note -- pillow talk after a passionate night does matter to ladies. In fact, it's as important for a healthy relationship as sex.
Researchers at the University of Michigan have carried out the study and found that women whose partners nod off to sleep after being intimate are actually left feeling insecure and wanting attention.
The study has found that cuddling and talking after sex is a crucial way for a couple to express their commitment to each other, the 'Daily Mail' newspaper reported.
The researchers have based their findings on an analysis of 456 people who were surveyed for the study.
Lead researcher Dr Daniel Kruger said that the study of couples' sleeping patterns found men often fell asleep first.
Dr Kruger said: "When their partner feel asleep first, they craved that bonding time, for expressions of affection and endearment, and felt it was lacking. "A woman could be pregnant. Although with contraception that may not be the case anymore, we still have this psychology, and the post-coital time is when the couple makes promises to each other and establish commitment. "The time couples spend together after sex might be as important as what happens before it in terms of building the relationship yet it has rarely been studied."
The researchers claim that men may have developed a tendency to fall asleep first to avoid any conversations about commitment.
"For men, in evolutionary terms there's more of an incentive to have other sexual partners to advance their reproductive success whereas for women there is more incentive to secure the relationship," he said.
The findings have been published in the 'Journal of Social, Evolutionary and Cultural Psychology'.
