PHOENIX — A lot of people may stand in line to buy the new iPhone 5 at Apple stores on Friday morning, but does that betray a deeper psychological issue?

Valley psychologist Dena Cabrera can understand why people want an iPhone. She laughed as she said, “I have an iPhone, and I would literally sleep with mine if I could. Just kidding!”

For many people, standing in line all night to be the first to buy something gives them kind of a thrill, but Cabrera said some do it because they’re trying to define themselves using exterior objects.

“There’s that innate feeling in us that we want to be the first to experience things so that we can brag about it,” she said. “We can have that identity of this is what I own. This is what makes me me.”

Cabrera said that standing in line all night to buy something is fine once in a while, but if more often than that could be a problem.

“You have to step back and say ‘Gosh, is this going to interfere with my responsibilities?’ ” she said. ” ‘Am I going to be able to function tomorrow? Am I going to be able to go to work? Is this going to be a problem?’ ”

Cabrera said that if a person needs to stand in line all night to buy a product or going to a midnight showing of a film becomes “constant and consistent … that’s when you have to kind of re-evaluate your priorities,” she said.