Debby calls her 26-year-old daughter Beth three times a day - and might add a few daily texts on top of that.
Mother and daughter, both of whom live in Denver, are close, much more so than when Beth was a teenager.
"We talk about health, work, food, shopping - just touching base," said Debby, 60, who was shy about using her last name. "I am just checking to see if she's alive."
A study published this week in the journal of Scientific Reports, suggests that as women age, they shift their focus of intimacy from their husbands to adult daughters - even as their husbands continue to retain their wives as their closest confidantes.
Researchers from Britain's Oxford University and Boston's Northeastern University did an analysis of two billion cell phone calls and a half billion text messages from a mobile telephone carrier in a European country over a seven-month period. The contact most frequently called was considered the "best friend."
The study said that in early adulthood, men and women focus most on their romantic partner. With women, that continues until about age 27. But when they reach their 40s, they shift attention away from the spouse to the daughter. And that relationship strengthens over time, peaking at about age 60.
Men, at least in their cell phone communication, stick with a female best friend - presumably their wives, according to the study. They call their sons and daughters equally.
Researchers suggest that the shift in communication may be biologically driven as women in their childbearing years move closer to motherhood. Debby agrees.
"It's a natural progression of things," she said. "Also, I think it's a way of teaching her things - how to view the world, knowing she is coming closer to my shoes. She's more like a friend."
But her daughter Beth views the relationship differently, and Debby admits that she might consider her a "helicopter parent."
Beverly Hills psychoanalyst Fran Walfish said that while she appreciates "warm and close" families, when the lives of mothers and daughters become too intertwined, it can signal trouble in the husband-wife relationship.
"I am wondering if the women who were looked at in this study, they turn to their daughter because the relationships and communication with their husbands had decreased and fallen off track as they aged."
The "main requirement" for a healthy coupling is that the male and female "create or establish a reasonable separation from their family of origin," said Walfish, author of the 2010 book, "Self-Aware Parent."
"The new husband is first, front and center," she said. "What that means is the mental space that is taken up in one's mind of who we think about has to be husband first, then, children, then parent."
Adolescents need to separate to enter the world as adults, according to Walfish. "It's necessary to create the bricks and mortar of the foundation of the couple and the foundation of a new family."
Walfish said she has seen a rise in the number of couples in their 20s, 30s and 40s coming in for counseling because of "mother-in-law problems" … " I never get the complaint about fathers-in-laws."
She agrees that biology may drive aging mothers closer to their daughters, especially as they become grandparents. "That's a positive and wonderful thing," she said. "But if reasonable boundaries aren't created, it can be poison or toxic."
Mothers like Debby say that constant calling and texting their daughter has nothing to do with their love of their husbands.
"She's much more interesting than he is," she says. "And I like her opinion on things."