CAMBRIDGE, Mass. — LAST spring, I had the occasion to spend a day with the actor and comedian Aziz Ansari discussing our mutual interest in the psychology of texting. As we walked through Los Angeles, people approached him every few minutes not to ask for an autograph, but to demand a photograph. Mr. Ansari is gracious to his fans. He explained that instead of a photograph, he would offer a conversation. He inquired about their taste in music, what they liked about his performances, his stand-up, his sitcom “Parks and Recreation.” His fans were mollified but they were rarely happy. They had to walk away with nothing on their phones.