James Cutting and Kacie Armstrong at Cornell measured more than 31,000 shots from 24 films made between 1940 and 2010. The wider the shot, the longer it stayed on screen: about 8 seconds for the widest, about 2.5 for the closest. Then they timed 21 students judging happy or disgusted faces at four sizes: the smaller the face, the slower the answer. Only by about 50 milliseconds on a white page; in real film frames, about three times that. The editor Walter Murch asks: can you read the expression in the actor's eyes? If not, use the next closer shot.

The room, the stand-in and the face are our own models, built and lit in code.

Small face, give it time. Big face, cut sooner. How long would you hold it?

Sources: Cutting and Armstrong, "Facial expression, size, and clutter", Attention, Perception & Psychophysics 78 (2016); Walter Murch, In the Blink of an Eye (2001).
Music: our own, played on GarageBand instruments. Sounds: made by us.