“Ellie’s the third leg of the stool,” explains Rizzo. “For the past century, scientists only had good data about two of the three streams of information we can glean from people. There’s what people say about themselves, self-reporting, and what the body can tell us, biophysical data like heart rate and galvanic skin response. But there’s also behavior—our movements and facial expressions. These have always been hard to assess and, typically, we could only get at them through subjective observations. Ellie gathers objective, high-quality data.” With
