Symbol grounding and the origin of language

Organisms’ adaptive success depends on being able to do the right thing with the right kind of thing. This is categorization. Most species can learn categories (1) by direct experience (“induction”). Only human beings can learn categories (2) by word of mouth (“instruction”). Artificial-life simulations have shown the evolutionary advantage of instruction over induction and human electrophysiology experiments have shown that these two radically different ways of acquiring categories still share some common features in our brains today. Graph-theoretic analyses reveal that dictionaries consist of a core of more concrete words that are learned earlier, by direct experience (induction); the meanings of the rest of the dictionary can be learned by definition (instruction) alone, by combining the inductively grounded core words into subject/predicate propositions with truth values. We conjecture that language began when attempts to communicate through miming became conventionalized into arbitrary sequences of shared, increasingly arbitrary category names that made it possible for members of our species to transmit new categories to one another by defining and describing them via propositions (instruction).