Humans learn at a very young age to distinguish faces. In fact, studies have shown that an infant will pay closer attention (i.e. stare longer) at a face than any other object, no matter how colorful.
The human face plays an important role when answering the question what is it that makes humans different from all other animals?
Many scientists remark that humans have the most expressive face on the planet.
ABC News reports that this probably played a role in the previously accepted idea that we are the most emotional complex animals simply because scientists could not see such expressive emotions in other species.