Acquisition and cross-setting generalization of manual signs with severely retarded individuals.

Four adults with severe intellectual disability learned manual signs.

A speech clinician used a transfer-of-control procedure. She first guided each hand, then faded help until the client signed alone.

The team tracked if the signs also appeared with new staff and in new rooms.

All four people learned the signs. Some used them right away with other adults and in the lunchroom. Others needed extra practice before the sign showed up anywhere else.

Generalization was spotty, but it did happen for every participant.

Striefel et al. (1974) did the same prompt-fade trick ten years earlier. They moved control from hand cues to spoken words in teenagers with ID. C et al. simply swapped the end target: manual signs instead of verbal answers.

Nangle et al. (1993) later copied the logic with preschoolers who had no disability. The kids learned to answer questions out loud. The pattern is clear—transfer of control works across ages, diagnoses, and response forms.

Stasolla et al. (2015) push the idea further. They gave kids with cerebral palsy a microswitch laptop so they could “speak” without signs. The 1984 study shows the first step: teach the hand movement; the 2015 study adds tech when hands alone can’t do the job.

If you run programs for adults or children who don’t speak, start with hands-on help and fade it fast. Don’t wait for perfect generalization—plan extra sessions in each new place or with each new helper. The old procedure still works and sets the stage for high-tech options later.