Effects of Lag Schedules and Response Blocking on Variant Food Consumption by a Girl with Autism

One girl with autism ate only three foods. The team set up a lag schedule. She had to pick a new food every third bite to earn a reward.

When she reached for the same food twice in a row, the therapist gently blocked her hand. They tested this across five foods and three schedule sizes.

Blocking plus the lag schedule tripled the number of different foods she ate. The gains held even when the schedule got easier.

She kept eating new foods weeks later without blocking. The combo worked where lag alone had failed before.

Diemer et al. (2023) extends this idea. They added a 5-minute food test before using response blocking. This shows you can screen foods first, then block repeats to slow rapid eating.

Phillips et al. (2025) sounds like a warning. They found response blocking can increase, decrease, or wobble behavior across kids. This seems to clash with Silbaugh’s clear success. The difference: Silbaugh paired blocking with a lag schedule and one clear rule. Phillips tested blocking alone.

ALee et al. (2022) used only positive reinforcement and also grew food acceptance. Their kids were non-verbal and in a school. Silbaugh’s single-case design shows blocking adds value when praise alone stalls out.

If you have a picky eater stuck on three foods, try a lag 3 schedule plus gentle blocking. Tell the child, “Pick a new food every third bite.” Block any repeat reach. Fade the block once variety rises.