Short-form video is judged in its first moment, and that judgement determines everything afterwards. The reason is the physical design of the feed rather than any change in attention spans.
The feed makes leaving free
A vertical feed places the next video one gesture away, with no menu, no selection and no cost to abandoning what is currently playing.
Traditional viewing required a choice before playback and a further choice to leave, and both frictions kept viewers in place long enough for a video to establish itself.
Removing them means every moment is a decision point, and the first moment is where the largest share of viewers make it.
Early departure is the strongest negative signal
Distribution systems weight immediate exits heavily, because a viewer leaving within the first moments is unambiguous in a way that later departure is not.
A video losing most of its audience immediately will not be shown widely, regardless of how strong the remainder is, since the system never gathers evidence about the remainder.
This is why an opening is best understood as a distribution mechanism. It determines the size of the audience that will ever see anything else in the video.
Openings work by creating an open question
What holds a viewer is an unresolved state, meaning something is visibly happening whose outcome is not yet clear and will become clear shortly.
Conventional openings do the opposite, establishing context and identity before anything begins, which supplies information without creating any reason to remain.
The practical form this takes is starting inside the action rather than before it, so the first frame already shows a situation in progress.
Audio carries the first moment as much as picture
Many feeds play with sound, and an abrupt or unclear first second of audio produces departure just as reliably as a static image does.
Speech that begins immediately, without a breath or a settling pause, measurably outperforms the same line preceded by a moment of silence.
Where the principle is misapplied
Openings engineered purely for retention, without connection to what follows, produce departure a few seconds later once the mismatch becomes apparent.
The systems measure the whole curve, so an opening that holds viewers only to lose them at three seconds is scarcely better than one that loses them at one.