Generation gap: Boomers, Gen Xers are reining in their spending.

How deeply ingrained in your life was the prerecession spending addiction?

Look to your birth certificate for clues.

That's one place Philadelphia University fashion-industry management professor Natalie W. Nixon checks when pondering how consumers superheated the nation's economy, only to be cooling it down now, one unspent dollar at a time.

Nixon, who studies buying behavior and has worked in apparel manufacturing, notes that she is 39 and a member of Generation X - a group whose spending habits fall somewhere between those of the baby boomers and their children, Gen Y.

And though the almighty American consumer may seem like one big, hungry giant, she says all three segments of shoppers crashed into the recession with different spending habits.

They are readjusting differently, too, as shopping loses its mojo.

For most consumers, Nixon says, life before the Great Recession had become a matter of "lacking a certain level of consciousness and conscientiousness about what you're bringing into your life and why."

We had embraced instant gratification with the swipe of a credit card. Cheap labor at overseas textile mills sent clothing prices through the floor. All this turned shopping into a gluttonous feast.

"Why do you need a new set of dishes?" asks Nixon, who has worked with overseas manufacturers. "Just because you're bored and after work stopped in Target and they had these jazzily designed plates and flatware? Why do you need another pair of black shoes?"

Those days are over now for many, of course. As economists debate whether consumers will ever return to such decadence, this much is clear: Our shopping behavior was decades in the making.

During the Great Depression and the post-World War II economic boom, Americans spent only cash. In the 1950s, they spent with verve.

"It's a time of prosperity, and for the first time you've got a generation of Americans who are freeing up the reins about having to think so conscientiously all the time about savings," Nixon says.

Love that black-and-white TV? Buy a second. The phone in your kitchen lonely? Buy a few more. Boomers enjoyed childhood as their folks navigated the new wealth.

Thanks to advertisers, bankers, and corporations, shoppers started spending borrowed money like crazy in the 1980s, Nixon says. Credit-based buying kicked the consumer economy into high gear, as boomers were full-fledged adults, Gen Xers were in college, and Generation Y, the youngest of the batch, was being born.

Boomers and Gen Xers, raised in more financially conservative times, cautiously embraced the buying doctrine, delivered with toothy TV commercials showing happy people luxuriating on credit-bought vacations or in credit-financed new kitchens.

"I grew up at a time when my parents didn't just give me money," says Nixon, born in 1969. "I had to work for it, I had jobs throughout college."

Generation X became comfortable with credit cards, she says, but retained memories of more cautious ways.

"I thought long and hard before I bought a $70 bag for my first job," Nixon says, "and I paid it off in two payments because I was so nervous about it."

Generation Y, she says, has been surrounded by credit from day one. Its constituents have known little else.

"They are used to having options, they are used to having choice, they grew up expecting to have allowance, whether or not it was earned through work, and they also grew up pretty early on with retailers pushing a culture of consumption," Nixon says.

Credit card applications await freshmen in college dorm rooms, specialty retailers target even younger teens for credit cards, and Web sites encourage buying among 6-year-olds in virtual communities, Nixon says.

But the recession has prompted all age groups to reevaluate the worth of a penny earned.

Of the three, the boomers, closest to retirement, have most sharply pulled back on spending. "They have very little rebound room," Nixon says, referring to losses in retirement portfolios.

Gen Xers also are revisiting their values, given the need to support themselves and young families in the face of growing job insecurity.

"My generation, we're at an age . . . where we've got to think about sending children to college, and those funds have dried up and have been really tapped," Nixon says.

And the young adults who constitute most of the students she teaches have been sobered enough to perhaps rethink the necessity of owning seven pairs of jeans in different colors, cuts, and washes - tidbits they've shared with her in years past.

"I don't downplay how conscientious the Generation Y folks are at all," Nixon says, "because they are entering a dismal job market."