The most basic formula in first-order logic is P(x): one predicate, one variable.
It's also the most basic unit of communication — we say something (the predicate) about something (the variable). Delicious chocolate. Chocolate is delicious. Or, if you want to get fancy, you can throw in more formal machinery to specify that I believe chocolate is delicious, or that chocolate is only delicious when it's dark.
This is the background you need to understand why I was intrigued by a trend in social media, especially on Twitter and Facebook, to leave out the predicate entirely. Here are some examples:
In first-order logic, these are all missing predicates. What about that feeling or moment? Was the author shocked? Worried? Disappointed? Resigned? We get hints, to be sure, but we're not told.
The unpredicated tweet achieves its purest form of expression in the "this" tweet, which leaves out almost everything:
Again, we're not told what the something is that the author wants to tell us about this. Yet, clearly, there's communication going on here, and it's not just about what the author is reading or viewing or feeling at that very moment.
So what's going on?
Here's my pet theory. Social media is a low-bandwidth form of communication. It's not just that we're sometimes restricted to 140 characters, it's that we miss out on subtle vocal intonation, on facial expressions, on a wink-wink nudge-nudge. When we lose these social cues, we also lose common mechanisms for signaling intimacy and the boundaries of group membership.
Unpredicated tweets assume that the reader can fill in the missing piece. Beyond their surface content, they communicate some shared sensibility: "You'll respond to this just like I did. You and I are on the same page. You will get it." This interpersonal confidence — a sense of connection — is one the medium often loses. And when you only have 140 characters, or so, leaving something out that puts something back in is a pretty good trick.
Now I'm no expert on language, so I decided to consult someone who is — Carla Hudson Kam, a psychologist and professor of linguistics at the University of British Columbia in Vancouver. I asked her what she thought of my pet theory, and she raised some interesting points.
Hudson Kam noted that something was definitely missing from unpredicated tweets on more formal theories of language — those that attempt to model linguistic form and content after something like first-order logic. But they aren't so puzzling from usage-based perspectives, according to which the properties of language emerge from how language is used in context, not from a pre-defined set of rules. With some context, your prior experience with language, and general reasoning abilities, you can infer the intended meaning with reasonable reliability.
For the "this" tweet, Hudson Kam was reminded of early child language:
"Children often point and say 'that' (as opposed to 'this'). Sometimes it's a question, but often it's more of a way to interact, to engage in a moment of sharing — in this case, sharing attention to whatever the 'that' was. So again, a missing predicate, but much less sophisticated. The twitter versions really do convey something beyond just 'share my focus of attention,' they convey 'share my attitude about the this'. So it's a form of expression we've each had since we started talking, but we're using it in a much more sophisticated way."
Hudson Kam also proposed an alternative idea — that people assume everyone will react the same way to the "variables" in unpredicated tweets. So these communications aren't necessarily creating intimacy among the select (our followers or friends), but rather assuming similarity between people more broadly.
Finally, Hudson Kam noted that using social media well requires a lot of linguistic skill. That, in turn, requires reasoning about your audience and what they'll know and infer. "So the notion that a message is being conveyed by what is not there is entirely sensible," she says.
You can keep up with more of what Tania Lombrozo is thinking on Twitter: @TaniaLombrozo