Perception psychology: first information dominates interpretation of subsequent images — opening sequence anchors visual expectation. Kuleshov exploited this systematically.
The first shot of a sequence — or an entire film — shapes how we interpret everything that follows. This isn't mystical, but pure perceptual psychology. A film that begins with a dark, high-contrast facade immediately activates a specific reading: tension, danger, noir aesthetics. The next ten shots benefit from this predefined expectation — or fight against it. The primacy effect describes exactly this: the brain gives more weight to early information than to subsequent corrections.
Kuleshov systematically exploited this as early as the 1920s by combining an identical close-up of an actor's face with different preceding shots — soup, a playing child, an open coffin. The audience "saw" completely different emotional expressions, even though the facial shot was technically identical. The context — the primary information — overrode objective perception. This works just as well with color, light, and camera movement: an opening scene in cool blue sets a filter over all subsequent scenes.
On set and in the edit, this practically means: the first shot of a sequence is not interchangeable. It is not one of many — it is the interpretation of all that follows. Showing a face first with hard side lighting before later bathing it in soft light tells a different story than the reverse order. In the edit, this is immediately apparent: a misplaced opening shot can sabotage the entire emotional dynamic of a scene, even if the content cuts are technically clean. This is why the pacing of the first three to five shots is crucial — this is where the implicit promise is made, which the sequence must then fulfill or break.
The effect also works temporally: starting with very fast cuts immediately signals dynamism; slow fade-ins declare contemplation. And: the primacy effect explains why poorly conceived openings are so deadly. A film doesn't need to be perfect — but the first minute must orient and engage the audience. Everything else is a secondary effect.