Like a lot of predictable human activity, there's some brain science behind our animal giddiness. Researchers have just pinpointed the area of the brain that gets all glowy when we look at adorable furry things. They inserted electrodes into the heads of 41 epilepsy patients (who were already having brain surgery) and showed them pictures of animals, figuring, I guess, that if you have to get your head cut open, you might as well have something nice to look at in the meantime. With the directly inserted electrodes, the scientists could detect the activity of individual brain cells and see exactly which were activated given the stimuli.
Turns out our "cute centers" are located in the right-sided amygdala-- and pretty much exclusively there. It's a region once thought to be devoted to fear and fear alone, but new research shows it's involved in a lot of other feelings too. Upon seeing an animal picture, cells in the test subjects' amygdalas lit up much faster and brighter than they did with any other picture stimulus. That universal "aww" response happens fast and strong.
The researchers suspect the brain response might be more complicated than just a cute protocol, though. They showed pictures of adorable animals, but they also showed predators--creatures that we should, logically, be programmed to fear. There was no difference in response between harmless and harmful animals. Looks like we're just hardwired to respond and take notice when there's any kind of non-human creature around. It makes sense evolutionarily--those who could respond to predators more quickly would have a much better chance of survival, and I'm sure bonds with harmless animals (not to mention human prey) would increase one's chance of living as well. I'm not sure if the study's other stimuli included pictures of people or just neutral objects (I would guess our emotional learning center lights up similarly at the site of another human) but at least now we know the science behind our rampant, innate excitement over God's creatures.