Passengers flying through Boston’s Logan International Airport will notice the security screeners are chattier than usual, but it’s not an improved customer service policy. On Tuesday the Transportation Security Administration began a test-run at Logan of its SPOT program, which stands for Screening of Passengers by Observation Techniques. SPOT uses trained screeners known as Behavior Detection Officers (BDOs) to determine if passengers are a threat, based on their reactions to a set of routine questions. “The vast majority of passengers will experience a casual greeting conversation with the BDO as they go through identity verification,” a TSA spokesperson said. “A...