The Art of Word Learning
The art of learning words is not, it would seem, hard to master. Six-year-olds, for whom hand-eye coordination is still iffy and toy-sharing a contentious proposition, already possess a sophisticated vocabulary: around 9,000-14,000 words, according to Harvard University researcher Susan Carey. And yet many scholars, including the philosopher Willard Van Orman Quine, have noted that word learning should be extraordinarily difficult to master, since it involves mapping labels to events in the world, and real-world events are infinitely complex. If someone at a zoo points to a leopard and says “leopard,” is she referencing the entire creature? The spots? The slinky gait or the faux savannah backdrop? Or perhaps felines, or large animals, more generally?
But thankfully, we don’t just hear “leopard” once. We hear it again and again, when the leopard is close, or too far away for its spots to be visible. We hear “leopard” whether the creature is stalking or sleeping, while visiting the zoo or while watching an Attenborough special. We are likelier to hear “leopard” in the presence of leopards than elephants or flamingos or lions. That is, because every word (with very few exceptions) occurs in a slightly different set of contexts from every other word, we can use this entire set of occurrences to constrain our hypotheses about how to map word to world. Researchers call this “cross-situational learning,” and at least under optimal conditions we are pretty good at it.
But sometimes what a set of situations has in common isn’t obvious at all. Verbs, which describe often abstract relationships between objects, pose an especially difficult problem. We give presents at Christmas, directions at gas stations, kisses at dances, birth in hospitals, and advice all the time, and none of these events superficially looks much like the others.