The average American house size has more than doubled since the 1950s; it now stands at 2,349 square feet. Whether it's a McMansion in a wealthy neighborhood, or a bigger, cheaper house in the exurbs, the move toward ever large homes has been accelerating for years. Consider: Back in the 1950s and '60s, people thought it was normal for a family to have one bathroom, or for two or three growing boys to share a bedroom. Well-off people summered in tiny beach cottages. Now, many of those cottages have been replaced with bigger houses. Six-room apartments in cities like New York or Chicago have been combined. Is it wealth? Is it greed? Or are there more subtle things going on? Big picture is, they are fueling the local economy," says Pat Trunzo, a local builder. Trunzo says there's a different mindset among the wealthy today, compared to when his father started the family business. "Most of the big houses were visible from the road," he says. Now ... the wealthy "want their own private little enclave. And they don't even want the general public to know that they are there." For Trunzo, it's just a bit strange. But for John Stilgoe, a professor ... at Harvard University, it's emblematic. "The big house represents the atomizing of the American family," he says. "Each person not only has his or her own television - each person has his or her own bathroom. The family members rarely have to interact. And the notion of compromise is simply out one of the very many windows these houses sport."