The never-ending, ever-evolving prep style was originally a result of preparatory high schools (boarding schools) and Ivy League universities in New England during the 1950s. The dress codes at prep schools gave us the classic school uniform. The Ivy League gave us chinos and loafers. During its beginnings, "preppy" didn't include Ralph Lauren polo shirts. It was about the upper class, the elite - those who could afford to go to expensive schools and wear uniforms every day. These uniforms were to encourage exclusivity, tradition and feelings of belonging. They advertised the kind of lifestyle middle-class people could only dream of. Eventually, the preppy uniforms of the exclusive, influential and prestigious gave way to streetwear for the masses. Soon, one could claim to be of the influential upper class and yet have gone to public school. (Gasp!) Those who wear Ralph Lauren, Tommy Hilfiger or Calvin Klein today can claim the "right" to call themselves preps.
The current revival of original prep - plaid patterns, clean, crisp lines, cardigans and loafers - has been speculated by some to have resulted from the low-cut, highly inappropriate styles seen the past few years. There is, of course, no factual evidence this is true. (Senior project time, everyone. I'm still in that research-paper-writing mode.)
Today, the preppy style includes ribbon belts, oxford and polo shirts, cardigans, chinos, shirt dresses and just about anything else you might see upon visiting Rori Gilmore during her years at Chilton (prep school) or Yale University (Ivy League). Drape a cardigan around your shoulders, over either an oxford or a polo shirt. Bows and ribbons, A-line skirts and ballet flats are staples to this wardrobe. Boyfriend blazers would be a great way to get that prep look. Wear one over an oxford or even a simple T-shirt. Add a headband or a bow and you're all "prepped out!"