I'm not really into taking pictures of myself, but I love seeing your selfies. I don't care whether you're posing with some weird food item or standing next to that guy who kind of annoys me. That's because your Snapchat pic of a barf face is fulfilling an ancient biological urge that I share with my fellow humans.
Other animals like to sniff each other's asses or call to each other over the rooftops. But among humans, there's a long history and cultural tradition of locking eyes and positioning our faces so that other people can see the planes of our cheeks and the curves of our lips.
There's even a special region of our brains devoted to recognizing faces.
Almost two decades ago, MIT neuroscientist Nancy Kanwisher named it the fusiform facial area (FFA) in a scientific paper. It was one of the first parts of the brain's visual system that neuroscientists identified as having such a specific function. But Kanwisher and her colleagues later discovered that humans are so face-hungry that the FFA becomes activated even when we see cartoon or cat faces. Another study revealed that even emoticons and emoji can evoke a psychological response akin to seeing a photograph of a person's face.
This aspect of human cognition is so obvious that even non-humans have noticed it. A couple of years ago, researchers at Google built a neural network and unleashed it on a giant store of pictures taken from the web, hoping that it would find some patterns. After three days, guess what this proto-AI had learned? It had discovered how to recognize human and cat faces — because so many humans had posted them.
As you might guess, there are a lot of theories about why there was some evolutionary advantage to recognizing faces. Probably it had a lot to do with knowing our kin or friends, as well as knowing what they were feeling without needing to talk.
All this goes a long way toward explaining why I get excited when my Instagram friends post pictures of themselves in party outfits, or just sitting around with friends. At the moment I look into their faces, I feel a flash of kinship. I feel like they're smiling at me, or making that silly face just for my entertainment. It doesn't matter if I know that this person has like 10 thousand other followers in real life and she's probably smiling at the person standing behind her smart phone. I'm feeling something that comes from a place that's just a little bit beyond rationality. It's one of those emotional reactions I can't control.
That said, my instinctual reactions are also shaped by hyper-modern conditions. If I had lived 50 thousand years ago, my joy in facial recognition would probably be limited to members of my hunter/gatherer group. Today, via selfies, anyone can be a beloved recognized person to me. I don't know if this means we are expanding our capacity for benevolence using social media. But does suggest, intriguingly, that selfies are the opposite of selfish.
Annalee Newitz is the editor-in-chief of io9, and this is her column. She's also the author of a book called Scatter, Adapt and Remember: How Humans Will Survive a Mass Extinction.
Nancy Kanwisher, et. al., The Fusiform Face Area: A Module in Human Extrastriate Cortex Specialized for Face Perception [PDF], Journal of Neuroscience
Frank Tong, et. al. Response Properties of the Human Fusiform Face Area, Cognitive Neuropsychology
Quoc V. Le et. al., Building High-level Features Using Large Scale Unsupervised Learning,presentation at International Conference on Machine Learning
Owen Churches, Emoticons in Mind: An event-related potential study, Social Neuroscience
Karen L. Schmidt and Jeffrey F. Cohn, Human facial expressions as adaptations: Evolutionary questions in facial expression research, American Journal of Physical Anthropology