Sure, it’s soothing for pets to be stroked and touched by us, but we get a huge physiological payback too: Just a few minutes of petting a pooch signals our brain to crank up production of the hormones serotonin and oxytocin — two calming chemicals that make us feel more relaxed and at peace, according to research from the University of Missouri-Columbia. And running your hand against your dog’s fur also decreases levels of the stress hormone cortisol. The study only involved canines, but Niven suspects the same serenity boost can occur when you pet, nuzzle or rub any animal companion.