PERSONAL HEALTH : Express-Line Etiquette

Cash in fist, you hurry to the supermarket express line, where 10 items is the limit and you’ll breeze through. Guess again. Ahead of you is a blatant rule-breaker, a shopper with 15 or 20 items.

Hardly a surprise to John Trinkaus, a visiting distinguished professor of management at St. John’s University in New York who researches compliance at express checkout lanes. One of four express-lane shoppers breaks the rules, he found in his latest study.

“Overages” are generally limited to one to three pieces, says Trinkaus, who observed 750 express-lane shoppers of a Northeast suburban supermarket chain and reported the findings in the journal Psychological Reports.

“The most items over I saw was 19,” Trinkaus says. The results suggest to him that there is “some substantial tendency” not to play by the rules.

Despite the transgressions, neither shoppers nor supermarket checkers voiced objections. The silence might reflect a popular belief that there is “give” in everyday operating rules, speculates Trinkaus, who says he also remains silent when behind an express-line rebel. Saying nothing may also save time, he says.

Then again, silence might be urban wisdom. “Who knows?” says Trinkaus. “The person might hit me over the head with a leg of lamb or a can of soup.”