ABA Fundamentals

Increasing vocal variability in children with autism using a lag schedule of reinforcement.

Esch et al. (2009) · The Analysis of verbal behavior 2009
★ The Verdict

A simple Lag 1 schedule quickly makes nonverbal children with autism produce more varied sounds.

✓ Read this if BCBAs teaching early vocal or play variety to nonverbal or low-language learners.
✗ Skip if Clinicians whose clients already speak in flexible, novel sentences.

01Research in Context

01

What this study did

The team worked with two nonverbal children with autism.

They used a Lag 1 schedule: the child had to say a different sound each time to earn a reinforcer.

No new toys or prompts were added; only new sounds got rewards.

02

What they found

Both children quickly made more different sounds.

The number of new, untrained sounds grew right away.

03

How this fits with other research

Olin et al. (2020) ran a direct replication and got the same boost, but they added echoic prompts and visual aids for older, speaking kids.

Jones et al. (2010) extended the idea to play: a Lag 3 schedule made children build varied block towers without extra blocks.

Cohrs et al. (2017) went further, using Lag 2 after multiple-exemplar training to create flexible social answers in group lessons.

Together these studies show the Lag rule works from sounds to blocks to conversation.

04

Why it matters

If a child echoes the same word or play move, try a Lag 1 schedule first.

Reinforce only new responses for a few minutes each day.

The tactic is simple, needs no extra materials, and now has 15 years of replications across ages and skills.

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→ Action — try this Monday

Pick one echoic sound; deliver a reinforcer only if the child says a new version each time for ten trials.

02At a glance

Intervention
differential reinforcement
Design
single case other
Sample size
2
Population
autism spectrum disorder
Finding
positive

03Original abstract

Variability has been demonstrated to be an operant dimension of behavior (Neuringer, 2002; Page & Neuringer, 1985). Recently, lag schedules have been used to demonstrate operant variability of verbal behavior in persons with a diagnosis of autism (e.g., Lee, McComas, & Jawor, 2002). The current study evaluated the effects of a Lag 1 schedule on the vocal variability of 2 nonverbal children with a diagnosis of autism. Results showed systematic increases in variability during the Lag 1 schedule. Implications of lag schedules for speech and language training are discussed.

The Analysis of verbal behavior, 2009 · doi:10.1007/BF03393071