What is a motif in the short story "Harrison Bergeron?"

A motif is a recurring theme, character type, message, trope, or idea. The major recurring theme is the government's flawed notion of equality. The handicaps limit very talented people and provide no encouragement for those with less talent. This notion of making everyone "equal" actually just keeps everyone at a low, albeit common, level of achievement.
A major recurring device (motif) in this story is the sound transmitted to George's ear when his thoughts must be disrupted before he can have any cogent, complex experience of thinking. Early in the story, this occurs while he and Hazel are watching the ballet on television. Some of the ballerinas also get the noise in their ears. Evidently, they were attempting to think critically as well. The noise in George's ears occurs again and again. This repeating motif shows the extent to which his (and everyone else's) mind is controlled. When the ballerina reads the news bulletin that Harrison is a fugitive, George begins to think and he is hit again:

The realization was blasted from his mind instantly by the sound of an automobile collision in his head.

This recurring, crippling noise in George's ear is a good example of a motif which parallels the theme of oppression via the government's physical and mental control of the people.