When should environmental enrichment be modified or limited?

• A. Enrichment is irrelevant to experiments.
• B. Enrichment should never be modified.
• C. If enrichment interferes with experiments, safety, sanitation, or study endpoints, or it creates hazards.
• D. If animals appear bored.

Answer: (C)

Environmental enrichment is used to improve welfare while maintaining experimental integrity. It should be modified or limited when enrichment interferes with experiments, affects safety or sanitation, changes study endpoints, or creates hazards. Enrichment can influence behavior, physiology, and stress, which may confound data, so scientists may adjust or standardize enrichment to prevent confounding while still promoting welfare. If enrichment introduces dangerous materials, contaminants, or safety risks, it must be restricted. While signs of boredom can indicate welfare concerns, decisions about enrichment are guided by both welfare and experimental requirements rather than subjective impressions alone.