Linklater began filming Boyhood in the summer of 2002, planning to follow one character from age 6 to 18: As Mason, a small-town Texas kid being raised by a single mom, he cast an unknown 7-year-old named Ellar Coltrane and assembled his cast and crew for a few weeks every year, tracing Mason's story through childhood and adolescence.
Mason grows up before our eyes, in what can feel something like real time. The people around Mason change, too: His mother (Patricia Arquette) becomes slightly thicker around the middle, though her smile becomes more radiant. His sometime-absentee father (Ethan Hawke) doesn't change much physically, though bits of his boyishly optimistic aura fall away through the years. His older sister, Samantha (Lorelei Linklater, the director's daughter), starts out as a bossy mite — and enthusiastic Britney Spears impersonator — and grows into a self-possessed young woman. Mason and Samantha observe the behavior of their separated parents like junior scientists of humanity: They watch from an upstairs window as their parents argue outside. "Think he'll spend the night?" Mason asks hopefully. It's a kid's-eye-view of marriage so sharp it cuts through you.