Activation of each muscle group causes a specific change in facial expression. For example, pain-related expressions often include furrowed brows, elevated cheeks, squinting, wrinkled nose and ...

The patient grumbled and grimaced, but he refused to speak to his doctor.

If a mouse is in a lot of pain, an experienced handler may see it in the animal’s facial expression—its narrowed eyes and bulging cheeks. But, subtler facial expressions may be more difficult to match ...

Why it matters: University of Florida researchers have developed an AI system that can identify pain in goats by analyzing ...