Constance Young uses Caller ID to scope out whether potential boyfriends really did try to phone her. Corey Albright says that using another telephone company service, return call, to find out who called has become a teenage ritual. Alexis Henderson worries that her husband has become obsessed with figuring out who called and hung up.

They're using services that have been around for a decade. With Caller ID, a box attached to the phone displays the numbers of the last few callers; when a return-call user dials star 69 on the phone, it recites the number of the last caller in an electronic voice and then dials it.

But their experiences reflect increasingly common changes in phone behavior, thanks to a recent doubling in the popularity of the two services in the Washington area.

Two million, or 17 percent, of Bell Atlantic's 12 million customers in six states and the District use Caller ID, compared with 1 million in June 1995. And about twice as many people are using return call compared with last year, the company says.

Spokesmen for two major Caller ID equipment manufacturers, CIDCO Inc. and Lucent Technologies, said the service is becoming more popular nationwide. Lucent projects 4 million people will become Caller ID users in 1996, bringing the total to more than 10 million. And CIDCO, the largest manufacturer of the device, saw a doubling in sales from 1994 to 1995. Spokesmen for two other big phone companies, Ameritech and US West, said there has been a surge in both Caller ID and return-call use in their areas.

In addition to its heavy marketing, Bell Atlantic credits the increasing use to recent enhancements in the services.

For $6.50 a month, Caller ID originally displayed just the caller's phone number on the box. But starting a year ago, for an extra dollar a month, the device also displays the listed name for that phone number.

Return call, used by picking up any phone and dialing star 69, used to just call back the number that last rang that phone. But now the user also hears the number spoken first.

The features have long been criticized for chipping away at phone users' privacy, making it more difficult for people to keep their numbers secret. But those who use the new technology argue it can enhance privacy by giving people more control over whom they talk to and when. They talk of screening out zealous telemarketers, guarding family time and even checking the honesty of friends and acquaintances.

"For me, {Caller ID} was sort of an integrity thing," said Constance Young, a Washington paralegal in her forties. "It was a way of scouting out potential beaus."

Young said she was interested in a certain man but questioned whether he was sincere when he said he had tried to call. Then she got Caller ID. When she arrived home after work, she pushed a button to see a list of the last few dozen calls, and the inventory brought Young a pleasant surprise.

"It turned out to be wonderful because he was calling quite a bit," she said.

The return-call feature seems particularly popular among teenagers, in some cases leading to face-offs with parents over the phone bill. Bell Atlantic charges 75 cents for each use, unless a family subscribes to the service for $4 a month.

Corey Albright, 18, who lives in Prince William County, said he and his friends dial star 69 frequently. Whenever the phone rings and the caller hangs up without leaving a message -- a common occurrence among his peers -- curiosity gets the better of him, and he makes a "return call." But he said he often finds that the person on the other end of the line denies having called.

"When you call back, people deny it, especially girls," he said. "I call back, and it'll be like, Did you just call here?' And they'll say no."

The rock group REM captured the change in phone culture in a 1994 song titled "Star 69." A man catches his friend in a lie and calls him on it: "I know you called, I know you hung up my line, Star 69."

But knowledge is power, and power can get a bit ugly.

Alexis Henderson, of Salisbury, Md., said her husband is "obsessed" with the return-call feature. "It's like a vent for his hostilities," she said.

Henderson said her husband uses it to ring hang-up callers and ask, in a not-so-gentle voice, "Why did you call here?"

His habit recently led to something Henderson called a "Star 69 war." Henderson called a colleague on her way out the door. The colleague didn't answer, and Henderson hung up rather than leave a message, then left her house. The colleague, who was home, used return call to call back, and Henderson's husband picked up.

"My husband answers the phone, and {the colleague} says, Who's this?' " Henderson recalled. "And that immediately incensed him, and he said, Well, who's this?' So she hangs up. So he uses star 69 to call her back."

Finally, Henderson said, they recognized each others' voices and had a good laugh.

Gary Marx, a sociologist at the University of Colorado, said he worries that the return-call feature will foster more confrontation on the telephone.

"A significant percentage of all phone calls are a wrong number," he said. "It's easy to imagine people making good-faith errors and then . . . being berated for hanging up."

Peter Crabb takes it a step further. "This star 69 thing is kind of . . . creepy," said Crabb, a social psychologist at Pennsylvania State University. "You get people being very suspicious of one another, and wanting to get even. . . . You could look at this as a new channel for aggression."

Bell Atlantic dismisses such concerns. Although spokeswoman Joan Rasmussen agreed that the services are changing people's behavior, she said it's for the better.

"It gives people control," she said. "It gives them information that allows them to decide how they're going to handle a call."

But some still view the services as an invasion of privacy. Caller ID was stalled for years as Congress, consumer advocates, phone companies and regulators debated its effect on privacy.

Most agreed that Caller ID enhanced the privacy of those on the receiving end, by giving people a "peephole" on their phones allowing them to see who was calling. But it also posed privacy concerns for callers who don't want to give out their numbers.

Regulators answered that concern by requiring phone companies to enable consumers to block their numbers from appearing on Caller ID devices by dialing star 67 before placing a call. In the District, residents can ask the phone company to make sure their phone numbers virtually never appear on Caller ID, a service known as line blocking. In Maryland and Virginia, line-blocking service from the phone company is not available, although line-blocking devices can be bought at electronics stores for about $30. Maryland and Virginia callers also can use the star 67 feature.

Some aren't satisfied with those protections. Unlisted or unpublished numbers, they point out, will appear on Caller ID devices unless the owners of those numbers line-block them or dial star 67 before they make any call. And some people with private numbers who do not block them may not realize that their numbers are revealed in a voice recording whenever parties they call use star 69.

Bell Atlantic's Rasmussen said the company is working to fix the problem so that people cannot use star 69 to return calls from unlisted and unpublished numbers. The correction is expected by the end of next year.

Roslyn Crump, of Silver Spring, believes the two services' pros outweigh the cons. Her busy household would border on insane, she said, if the family of four didn't ignore some of their incoming calls.

"You could be walking out the door to an important meeting, and it's your aunt who talks your ear off {calling}," she said. "And you really don't want to hurt her feelings. . . . It's just better if you call her back when you have more time."

But the Orwellian overtones are menacing to some phone customers, according to Marc Rotenberg, director of the Washington-based Electronic Privacy Information Center.

"Caller ID basically remains a privacy sacrifice for customers who use the telephone system," Rotenberg said. "There are so many situations where people make calls when it's not necessary to disclose their identity. . . . The desire for anonymity is not going away."