Who doesn't love a pile of cute, wiggly little puppies? Dogs are called "Man's best friend" for a reason, but is there actual science behind why we love puppies so much? As it happens, there is. Puppies often have faces that are similar in size and proportion to human baby faces. Small round heads, with large eyes are thought to trigger something in the brain that floods us with an overwhelming urge to pick up a pup and start snuggling. It happens in the nucleus accumbens of the brain, which is where reward and pleasure are activated.
In a study that used functional MRI scans, mothers were asked to look at photos of their children and their dogs. Both the baby pics and the puppy pics lit up the same region of the brain, with some activity overlapping. All of the areas involved were part of the brain's system of processing reward and attachment. But why dogs? One study found that looking deep into puppy eyes is associated with large releases of the neurotransmitter oxytocin, and it makes people feel loved and happy. Spending time with dogs also ups levels of endorphins and dopamine. It's just what dogs do; they make us happy.