Behavioral engineering: stuttering as a function of stimulus duration during speech synchronization.

Researchers asked one adult who stuttered to read aloud while a metronome clicked.

They changed how long each click lasted—from 0.5 seconds up to 3 seconds.

They counted stutters and asked listeners if the speech still sounded natural.

Stuttering dropped as the click got longer, up to about 2 seconds.

At 2 seconds the speech stayed smooth and still sounded normal.

Shorter clicks helped a little, but 2 seconds was the sweet spot.

Fantino (1981) later showed adults can run their own fluency program. Instead of a metronome, they simply paused for 5 seconds each time they stuttered. The pause worked just as well and lasted a year.

Richman et al. (2001) moved the same idea to preschoolers. Parents praised fluent speech and gently corrected stutters. Kids stayed fluent without any metronome at all.

Rilling et al. (1969) ran a sister study in the same lab. They punished every disfluency with a lost penny. Both studies cut stuttering fast, but one used timing and the other used money.

If you work with older clients who like tech, try a metronome app set to 2-second beats. If they prefer self-help, teach the 5-second self-timeout from Fantino (1981). For young kids, jump straight to the parent-led Lidcombe praise-and-correction routine.