Every language on earth uses the same word for the temperature of a fire and the quality of a friend. Warm. This is not a coincidence, and it is not a metaphor. It is a body fact. This week's One Question takes a quiet, tender look at the word warm — and the surprisingly precise neuroscience underneath it.

Drawing on Williams and Bargh's landmark 2008 Yale study on embodied cognition (the one where holding a warm cup made participants rate a stranger as more generous), Stephen Porges' polyvagal work on co-regulation — including inter-species co-regulation, which is why a cat on your chest is doing something genuinely biological — and Mary Oliver's line about the soft animal of the body. With a small story about Lucy, my staple in the middle of the night.

What makes you feel warm inside?