This classic experiment shows the power of editing – as explained by one of its masters, Mr Alfred Hitchcock.
The Kuleshov Effect is the essence of film editing: cutting from shot A to shot B, then back to shot A, creates in the mind of the viewer a narrative – one that doesn’t inherently exist in any of the individual shots themselves.
Director Alfred Hitchcock demonstrates the Kuleshov Effect, as only he can:

The order changes the meaning.
– Filmmaker IQ
The experiment involved editing together different combinations of shot / reverse shot, and screening them to different audiences to different effect. Here are some of those original edits:

As Filmmaker IQ explains of Kuleshov’s theory, “the meaning of the film was not only in spatial composition, but in the arrangement of the shots” (my emphasis). He even re-creates the experiment:
The clip above is taken from Filmmaker IQ’s broader discussion of Soviet Montage Theory, which involved exploring the creation of meaning through editing images together:
“We Should Not Call It ‘The Kuleshov Effect”
“In early cinema, most editors were women. Why would you name something lots of women editors were doing after one man who observed them doing it?” Dr Karen Pearlman asks in Cutting Rhythms – Intuitive Film Editing. In her discussion with This Guy Edits, Dr Pearlman asserts that naming it solely after Kuleshov “erases the work of a whole lot of editors, many of whom were women“: