Gladwell’s goal in Part 3 is to address his second puzzle: Why do we often misjudge strangers after meeting them? Why does the extra information we glean from face-to-face interaction sometimes hurt, and not help, our ability to read them? He begins by looking at the work of psychologist Jennifer Fugate, who is an expert in a system called FACS (Facial Action Coding System). FACS involves assigning unique numbers to different muscular movements in the face, followed by a letter indicating the intensity of each movement.

Gladwell asked Fugate to analyze a brief segment from an episode of the TV show Friends. Her analysis showed that the actors consistently used facial expressions with moderate to high intensity, and that their facial expressions were exactly what you would expect for the emotions a character was feeling—a jaw drop when a character was surprised, a furrowed brow when a character was angry, and so on. The actors’ facial expressions were transparent—they provided an accurate window into the way the characters felt on the inside. Gladwell claims that this notion of transparency is the second tool that we use to make sense of strangers. When we haven’t had the time to really get to know a person, we rely on their outward behavior and demeanor to get a sense of what the person is thinking or feeling.