According to U.S. Government Principles, pain perceived by animals should be assumed in which situation?

The proper context for understanding the assumption of pain in animals relates closely to the principles of animal welfare and humane treatment as outlined by the U.S. Government Principles. When applying these principles, it is crucial to err on the side of caution and assume that animals may experience pain, especially when a procedure is known to cause pain in humans.

Choosing an answer based on the idea that pain should be assumed when the pain is treatable reflects an understanding of ethical considerations in animal research. If pain is acknowledged to be present and treatable, it implies a responsibility to mitigate that pain as much as possible through appropriate pain management strategies. This aligns with the principles that emphasize minimizing suffering in animals and ensuring their welfare in research settings.

The other choices do not sufficiently consider the ethical implications of assuming animals experience pain. For instance, assuming no pain simply because a procedure may be painless for humans ignores the physiological differences between species. While it might be assumed that procedures not causing human discomfort would do the same for animals, such assumptions can lead to inadequate consideration of an animal's subjective experience. Similarly, stating that pain should not be assumed if the animal shows no outward signs disregards the fact that animals may not always exhibit obvious reactions to pain. Lastly, the notion that