This is a summary. To read the whole story subscribe to BostonGlobe.com
Forget, for a moment, all the usual benefits of public transportation, like cutting greenhouse gases and reducing traffic. There is a new reason to ride the commuter rails: It provides an excellent laboratory for studying human behavior.
The most recent such study, conducted on a commuter rail platform, finds that mixing with people of different ethnic backgrounds can influence social acceptance, at first for the worse, but then for the better.