Earlier this month, Facebook made its largest ever acquisition: Instagram, the popular photo-sharing service that lets you snap, filter and send with the click of a button. While the fit seems to make sense - a major reason to use Facebook is to share photos; the more photos you share, the more time you spend on the site and the happier the advertisers - the US$1 billion ($1.2 billion) price tag raised many an eyebrow.
But should the price come as a surprise or is the purchase a visionary move? In making its offer for Instagram, Facebook has recognised the ever-growing importance of an impulse that is awfully hard to resist: the urge to share.
That irresistible impulse to post, to tweet, to "like" has evolutionary roots that far precede the advent of social media. Consider something that's known as the "communal sharing" norm. In an environment of scarce resources (i.e. the one that prevailed for most of our history), every existing resource has to be shared with others. Thus, what I find out isn't my exclusive prerogative - it's actually common property in case it can be beneficial to someone else. There's a bear in that cave; these berries may kill you. All important information to pass on and the quicker the better.
The facts may have changed, but the immediacy seems just as real now. It's hard to shake off the feeling that people are somehow missing out if we don't communicate what we've seen - and communicate it at once. Is it really so far from: "There's a bear in the cave" to: "Look at that adorable bear playing with the berries in that YouTube video"? We don't just passively take in information. We want actively to pass it on to others. We share emotions; we share thoughts; we share opinions; we share objects. We share because we're happy, angry, perplexed, upset, or any other strong emotion.
We also share to express identity - what I contribute defines a part of who I am; if I share funny stuff, I'm a funny gal; if I share useful information, I'm a helpful, altruistic person; if I share masterful, profound links, well, draw your own conclusions. And we share to build community - sharing with others can help us identify common interests and ideas. Seeing how others respond has been shown to help define how we ourselves think and feel.
And what about all those cat videos, that chat about Ryan Gosling? Most generate laughter and laughter, in turn, generates social bonds. So let's laugh together over this cat, or better yet, if we're in the same office, come over and we'll laugh together.
Social media have tapped into something quite fundamental and the sharing urge in human nature may stem from something more basic than anything else: simple arousal and the fight-or-flight response that we share with our distant ancestors.
In scientific terms, this means the activation of our autonomic nervous system; in simpler terms, that extra boost of energy, the quickened heartbeat, that tingling of nerves that says something in the environment has caught my attention.
According to University of Pennsylvania psychologist Jonah Berger, arousal puts all other explanations for sharing to shame. In a 2011 study, Berger invited students to watch a video clip: either a "neutral" segment or one of several "emotional" segments.
Berger found that feeling scared or enraged or amused provokes us to send on clips or information. It's the emotions characterised by high arousal that drive us to act. "If something makes you angry as opposed to sad, for example, you're more likely to share it because you're fired up,"
And though sharing urges aren't new they are now activated on a near-constant basis. One need only look at the proliferation of sites devoted to sharing exclusively - Reddit, Digg, Stumbleupon - to see the phenomenon in action.
I see, I react, I share. I become part of a community and your "likes" validate me. I feel rewarded with every retweet and endorsement, while conversely I feel sad if something just kind of plops into a virtual neverland. Was it something I said? In fact, being virtually rejected actually activates the same brain areas that are associated with physical distress, the dorsal anterior cingulate cortex and the anterior insula.
Social media make sharing easier than ever before. I have gone from Twitter neophyte less than a year ago to a compulsive sharer. Do I really have that much to share? Almost certainly not, but I feel like I do. And in that, I am far from alone.
Or perhaps I'm more alone than I think. Psychologist and novelist Charles Fernyhough once referred to Twitter - on Twitter, of course - as "a great example of what Piaget called 'collective monologues'. Lots of people chattering away with no attention to each other."
Indeed, a recent study suggested that individuals who ranked higher on emotional instability were more likely to share online, though not in person, echoing the findings of psychologist John Cacioppo that a greater proportion of online interactions correlates with increased loneliness and isolation. Clearly, not all sharing is created equally.
But in the end, it may not matter all that much. According to unpublished results by Eva Buechel, now at the University of Miami, online sharing can actually make us feel better, serving as a very real form of emotional therapy. It's as if every tweet that gets passed on, every link that is re-shared, activates our brains' pleasure centres, releasing endorphins in much the same way as physical pleasure, exercise, excitement or strong sensory stimulation.