DePaulo said both single men and women are discriminated against, but that women, especially those who have risen to prominence, are particularly, well, singled out.
In a 2004 interview with then Green Party candidate Ralph Nader, MSNBC's Chris Matthews asked how Nader could accuse Bush of being irresponsible when "he's raised two daughters; he's had a happy marriage. Isn't he more mature in his lifestyle than you are?"
"We hear more about women. They get it much worse. Single men are called bachelors, which doesn't sound that bad, but single women are called 'spinsters' and 'old maids,'" DePaulo said.
"We tell women they need to get married because 'your work won't love you back' and 'your eggs will dry up.' We also look at single women as extra promiscuous, basically sluts," DePaulo said.
DePaulo attributes some "singlism" to jealousy.
Married people, she said, want to buy into the idea that their spouses somehow make them more complete. "When they see single people just as accomplished and just as happy it rattles them," she said.
Despite the stereotype that singles are freewheeling individuals without any attachments, DePaulo said the research proves the opposite.
"In several national surveys, what's been found is that it's single people more than married people maintaining connections with friends, neighbors, siblings and parents. More than married people, its singles who do more work of connecting with other people."