How to Spot a Scoundrel; September / October 2012; Scientific American Mind; by Wray Hebert; 2 Page(s)

Imagine the original job interview. The first one ever, back on the prehistoric savannas of eastern Africa or maybe in an early agrarian society in the Fertile Crescent. A member of an unknown settlement may have wandered in and offered some irresistible service—lion-wrangling expertise, perhaps, or Herculean strength in the field. Unlike in a modern job interview, early humans had no résumés, LinkedIn profiles or letters of recommendation to guide them. The fundamental idea, however, was the same: somehow the interviewer had to judge, in a brief interval, whether the applicant—a complete stranger—was trustworthy. Bringing on a sordid character as a business partner or as a steward of your goods could endanger your livelihood or even your personal safety.

To boost the odds of choosing a solid relationship and rejecting a dicey one, our ancestors might have learned to detect subtle, unintended signs in that initial, face-to-face interaction. Indeed, how do we make these judgments nowadays? Discerning the motives of strangers is a skill we rely on all the time. Every time you walk into a used-car lot or shop around for a home contractor or financial adviser, you are using your wits to pick someone trustworthy—and to avoid scoundrels.