THURSDAY, March 24, 2011 (HealthDay News) -- Not only is holding the door open for others a nice gesture, it's also a nod to the physical effort of those involved, researchers report.
Their study, to be published in Psychological Science, combined two seemingly unrelated fields -- altruism and motor control.
"The way etiquette has been viewed by Emily Post -- that you're being proper by following social codes -- is undoubtedly part of it," David A. Rosenbaum, of Pennsylvania State University, said in a journal news release. "Our insight is there is another contributor: the mental representation of other people's physical effort."
"Substantial research in the field of motor control shows that people are good at estimating how much effort they and others expend," he said. "We realized that this concept could be extended to a shared-effort model of politeness."
He and a colleague analyzed videotapes of people approaching and passing through the door of a university building.
"The most important result was that when someone reached the door and two people followed, the first person at the door held the door longer than if only one person followed," Rosenbaum said. "The internal calculation on the part of the first arriver was, 'My altruism will benefit more people, so I'll hold the door longer.'"
The researchers also reported that people who noticed someone holding the door for them increased their pace, helping to "fulfill the implicit pact" between themselves and the door holder "to keep their joint effort below the sum of their individual door-opening efforts."
Rosenbaum added that the shared-effort model should not lessen the appreciation of good manners. "Here are people who will probably never see each other again, but in this fleeting interaction, they reduce each others' effort," he said. "This small gesture is uplifting for society."
The University of Oregon has more on politeness.