Autism & Developmental

The effects of an environmental "enrichment" program on the behavior of institutionalized profoundly retarded children.

Horner (1980) · Journal of applied behavior analysis 1980
★ The Verdict

Toys plus immediate reinforcement for touching them beats toys alone at slashing self-injury in profoundly delayed children.

✓ Read this if BCBAs in residential or day programs serving clients with severe ID and self-injury.
✗ Skip if Clinicians whose caseload is already using function-based DR plus matched leisure items.

01Research in Context

01

What this study did

Staff added bright toys to the dayroom of a state hospital.

They also praised and handed small treats when children touched or played with the toys.

All kids had profound intellectual disability and frequent self-hitting.

The team compared toys-only weeks with toys-plus-praise weeks.

02

What they found

Toy enrichment alone did little.

When staff also reinforced every adaptive touch, self-injury dropped and real play rose.

Gains held for weeks with no extra training.

03

How this fits with other research

McMillan et al. (1999) later dropped the praise and still saw self-injury fall.

They first asked each adult to pick favorite items, then gave only those items.

The study shows enrichment can work without DR if you tailor it to individual likes.

Fournier et al. (2004) kept the toys and added friendly talk and smiles.

Happiness rose even higher, hinting that social enrichment is a useful extra layer.

Leif et al. (2026) confirms the core lesson: reinforcement is the active piece.

Their clients only improved when engagement, not just self-monitoring, earned rewards.

04

Why it matters

You can cut severe self-injury without restraints or medication.

Start by filling the space with varied, easy-to-grasp toys.

Watch for any adaptive contact and immediately follow with praise, a bite of food, or brief play with you.

If the room already looks like a toy store but problem behavior persists, check whether reinforcement is actually happening.

Pair this setup with preference assessments, as McMillan et al. (1999) did, to keep items powerful, and add social elements, as Fournier et al. (2004) did, to lift mood.

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→ Action — try this Monday

Place three new toys near one client and deliver a preferred edible each time their hand contacts a toy for five minutes.

02At a glance

Intervention
differential reinforcement
Design
single case other
Sample size
5
Population
intellectual disability
Finding
positive
Magnitude
medium

03Original abstract

This study determined the effects of procedures designed to "enrich" the physical and social environment of an institutional ward on the "adaptive" and "maladaptive" child, adult, self, and object-directed behaviors of five profoundly retarded ambulatory females. Behavior observed in two treatment conditions, an environment "enriched" with toys and objects and an "enriched" environment coupled with differential reinforcement of adaptive behavior, was compared to behavior occurring in corresponding baseline or "austere" conditions and during a period of noncontingent reinforcement. The results generally revealed: (1) little change in adaptive and maladaptive child and adult-directed behavior across conditions, (2) an overall higher incidence of adaptive object-directed behavior and reduced self-directed maladaptive behavior in each treatment condition from that observed in corresponding control conditions, and (3) the use of an "enriched" environment and differential reinforcement of adaptive behavior resulted in maladaptive self-directed behavior being reduced and adaptive object-directed behavior being icreased beyond that observed in the "enriched" environment alone. These behavioral gains were largely maintained during a follow-up condition by continuing the "enriched" environment and transferring the responsibility for differential reinforcement to direct-care staff.

Journal of applied behavior analysis, 1980 · doi:10.1901/jaba.1980.13-473