Pets aren't wonder drugs. Here's why we love them anyway.

Why is there such a mismatch in public perception about pets as a panacea and the evidence for it?

I think it’s about a puzzling and unusually unique effect pets give to people, which is what I call the trustworthiness effect, which hasn’t received a huge amount of attention in the press, but it has been replicated in studies in several different countries. People with animals, or as simply described as having a friendly dog with them, instantly become more trustworthy in the eyes of the person who’s encountering that person or having that person described to them. I think it actually explains quite a lot — people are believed when they tell nice stories about animals. Whether that applies to news reports as well, I’m just guessing, but I think it’s a reasonable explanation. I think it also explains a lot of the effects of animal-assisted therapy. The magic is actually in making the person with the animal much more approachable. In a senior residence, it’s not simply the seniors who find the visitor a good person to talk to, but the staff finds the visits beneficial as well. It makes the whole place seem a bit more homely. The dog, or whatever animal, is changing people’s perception of the person doing the therapy. This is the trustworthiness factor, and it explains quite a lot of our biases.