An Evaluation of Lag Schedules of Reinforcement During Functional Communication Training: Effects on Varied Mand Responding and Challenging Behavior

Two children with autism got FCT for problem behavior. The team compared two reinforcement rules: Lag 0 (reward every correct mand) versus Lag 1 (reward only if the mand differs from the last one). They used an alternating-treatments design so each child experienced both rules in the same session.

When the rule switched to Lag 1, both kids instantly used more varied mands. Problem behavior stayed low in both conditions. The study showed you can boost variety without inviting a burst of problem behavior.

Stevens et al. (2018) took the idea further. They thinned FCT up to Lag 5 and still saw low problem behavior plus high mand variety. Their data extend Adami’s finding: the benefit holds even when you stretch the lag requirement.

Galuska et al. (2006) used a different thinning tool—multiple schedules—to keep mand rates manageable. Adami’s Lag 1 does the same job for variety instead of rate, showing two compatible ways to thin FCT reinforcement.

Donahoe et al. (2000) first taught kids to tolerate delayed reinforcement during FCT. Adami adds lag-based variety as another safe thinning option that does not bring problem behavior back.

If a client repeats the same mand, flip the rule to Lag 1 for a few trials. You will see new topographies pop out right away and problem behavior stays quiet. No extra toys, no new tokens—just a quick schedule tweak you can start Monday.