The "Hello, I'm a Mac, and I'm a PC" ads were one of the most memorable ad campaigns of our time. The ads showed Justin Long as the hipster embodiment of Mac users while John Hodgman was the stiff generalization of PC users.

The point of the ads presented viewers with a question put out by Seth Stevenson at Slate: "Would you rather be the laid-back young dude or the portly old dweeb"?

The campaign suggested that people who buy Macs are pretty much cooler, and have different personalities than those who prefer PCs. Which is actually a fact that's hard to find. There's not much evidence in personality differences between users of competing brands.

Psychologist Jeffrey Nevid of St. John's University recently wondered whether the personalities of Mac and PC users really differed as the ads suggest. Nevid had a good study sample to play with. Each incoming of St. John's students allows them options of either brand with the cost added to tuition fees.

Nevid and doctoral student Amy Pastva gave personality questionnaires to 108 students and searched for any link between personal traits and choice of computers.

Nevid and Pastva found no significant differences between computer users on the classic Big Five personality traits. "You couldn't pick them out or discern one group of owners from another based on personality," Nevid. "So there is no Mac personality so far as we can tell, or PC personality."

The researchers found that Mac users identified more closely with their computers than PC users did. When they saw images of Macs, they felt a connection too them that didn't exist as strongly for those who owned PCs. Is this the Mac effect?

Could this be the reason why the Mac-PC campaign remains so memorable after so many years?