It’s a continuation of the kind of intensive parenting that has become the norm in the United States. Today’s parents, especially mothers, are spending more time and money on their children than any previous generation — on things like lessons, tutors and test prep. Many parents’ anxiety only intensifies after 18, when children start the education and jobs they’ve been preparing for.

“Professional helicopter parents are really focused on using education to get their children into a professional career,” Ms. Hamilton said. “Their goal is basically to prevent their children from ever making a mistake.”

This kind of behavior is most prevalent among privileged parents, those with collegiate experience and wealth. In places with the biggest gaps between the rich and the poor, rich parents spend an even larger share of their incomes on their children, a recent paper found. The bribery scandal shows how far some parents will go — in one example, parents were accused of paying $1.2 million to help get their child into an Ivy League college.

More commonly, financial help comes in the form of tuition or rent payments. Parents used to spend the most money on their children during high school, according to Consumer Expenditure Survey data analyzed by the sociologists Sabino Kornrich and Frank Furstenberg. But now they spend the most before age 6 and after age 18 and into children’s 20s.

The increases in later years are because so many more children are going to college, which has become much more expensive, Mr. Kornrich said. Also, about a third of children this age still live at home. In the new survey by Morning Consult and The Times, about two-thirds of those who lived with their parents said it was because they could not afford to live on their own or were still in school.

One in three parents said they gave their 18-and-over children $100 or more a month, and 44 percent of those with children in college made tuition or loan payments for them. When asked at what age people should be financially independent from their parents, the largest share of young people said 25 to 28.

Recent research shows that even parents who can’t afford to give their grown children money increasingly provide them with significant support of other kinds. In the survey, wealthier parents were more likely to report giving their children money than less affluent ones were, but many nonfinancial measures of parental support remained consistent across income and education levels.