Everyone believes that humans have a Universal Grammar (UG). Why? Because it is a one step conclusion licensed by a trivial (and it is trivial) inference from one obvious factual premise (viz. humans are linguistically capable beings) and one major premise (viz. if humans are linguistically capable then there are some mental properties on which this capacity rests). As UG is the name we give to these mental properties there cannot be a real debate about whether humans have a UG. What has been contentious is what UG looks like. In what follows I discuss two features that generative linguists attribute to it: (i) UG is exclusive to humans and (ii) UG is linguistically specific. Chomsky, for example, has claimed both properties for UG. Let’s consider these in turn.
First what does “species-specific” mean? One thing it means is that UG is a property of humans the way that bipedalism or opposable thumbs are. Human genetics insures that individual humans normally (i.e. exempting pathological cases) come equipped with the capacity to walk erect, to grab stuff and to acquire and use a language. So, just as tigers are biologically built to have stripes, and salmon to return to their birthplaces to spawn so too humans come biologically equipped to develop linguistic facility. The empirical basis for this observation is overwhelming and not at all subtle. Anyone who observes language acquisition in the wild cannot fail to notice that human children (regardless of socio-economic status, religious affiliation, birth marks, head size, overall IQ or anything else short of pathology) when reared in a linguistic environment come to acquire linguistic competence in the native language they are exposed to. This observational truism leads smoothly to a related truism: that the capacity to develop such linguistic facility is due to mental equipment that individual humans share simply in virtue of being human.
These truisms conceded, even if UG is species specific to humans it does not imply that UG is exclusively a human endowment. After all the observation that humans come genetically packaged with a four chamber heart does not imply that other animals do not. Nonetheless, as a matter of fact, it appears that whatever humans have that allows them to develop linguistic competence is not widely shared. Concretely, so far as we can tell (and take it from me, many investigators have tried to tell!), nothing does language like humans do. Apes don’t. Dolphins don’t. Parrots don’t. Or at least they don’t obviously. While it takes considerable effort to show that other animals show language-like behavior, nobody will win a Nobel for demonstrating that 5 year olds (or even 2 year olds) talk. Thus, it’s a safe bet that whatever is going on in the human case is qualitatively different from what we see in other animals.
This said, it is worth noting that the program of describing UG wouldn’t change much were it established that other animals had one. Depending on which animals it was it might raise additional questions of how these UGs evolved (other apes? look for common ancestor; apes and dolphins? look for language as correlate of brain size; birds and bees? who knows). If other animals talked we could (at least in principle) investigate UG by studying how they acquired and used language, though the difficulties of studying UG in this way should not be underestimated. The biggest bonus would likely arise if we decided to treat these non-human talkers as possible targets for the kinds of experiments that are morally and legally forbidden on humans (cut them up, put them in Skinner boxes), though if they really talked like us we might be squeamish about treating them the way we treat white mice, chimps and cute bunny rabbits, though considering the unquenchable (blood thirsty?) desire for pure knowledge that homo sapiens regularly displays even pleading animals might not be safe from our inquisitive minds. However, excluding such scenarios, finding another species that talked just like we do would not substantially change the research problem. In fact, it would not make it appreciably different from studying UG by investigating the grammatical properties of different languages (English, Chinese, ASL etc.), something that generative grammarians already do in spades. So though it appears as a matter of fact that UG is exclusively a feature of humans, if the aim is to describe UG it does not much matter that this is so.
Let’s now consider the suggestion that UG is a linguistically specific capacity, to be understood as the claim that UG’s cognitive mechanisms are sui generis, different from the cognitive mechanisms at work in other areas of cognition. There is a stronger and a weaker version of this claim. The stronger one is that all (or most or many) of the cognitive powers that go into linguistic competence differ from those that support other cognitive capacities (e.g. the capacity to identify objects, recognize and “read” other minds, understand causal interactions, navigate home, keep track of where and when you hid your food, etc.). The weak one is that UG enjoys at least one cognitively distinctive feature. Current speculation among generativists leans towards the weak claim. Much current research in syntax (especially that which flies under the flag of the Minimalist Program) aims to reduce the linguistically specific mechanisms of UG to a small core. Chomsky, for example, has argued that the only real distinctive feature of UG is (hierarchical) recursion (a product of the operation Merge), the property whereby the outputs of rules can be treated as inputs to these same rules. This allows for the generation of endlessly large linguistic objects, a fact that sits well with the observation that there appears to be no upper bound on the size of admissible phrases and sentences in natural languages.
How reasonable is this second claim? To my mind, it is almost ineluctable for the following reasons. First, if as discussed above, humans have UG but other animals do not then one plausible reason for this is that humans have at least one mental power that other animals don’t. The alternative is that human cognition is not qualitatively different from that of other animals but only quantitatively so; all animals share the same basic mechanisms just that humans have more horse-power under the cranial hood. This
option is a favorite of those excited by general learning theories. They tend to be of an empiricist bent (something we will discuss in a later post). On this view, the same cognitive powers are used in every area of cognition, including language. There are two kinds of puzzles this empiricist conception runs into in the domain of language. First, the species specificity problem noted above; why do only humans talk? The second is the separability of linguistic competence from other forms of cognition. It appears that linguistic competence is independent of most other kinds of cognitive competence, e.g. IQ, face recognition, etc. Why so if all involve the same general all purpose cognitive powers? Were linguistic competence a product of general cognitive factors it would be natural to expect that success in acquiring linguistic competence tightly correlated with other cognitive achievements. But it appears that it does not; both the rich and the poor, the high IQed and the low, those with good memories and bad all seem to acquire linguistic competence at roughly the same rate and roughly the same way.
The second reason for thinking that UG involves at least one special cognitive feature is that it would be quite surprising biologically if it did not. Many animals have (almost) unique capacities (think echo location in bats, or navigation in ants). These capacities supervene on distinctive cognitive powers (e.g. in ants, the built in capacity to form a compass oriented map using sun position as anchor). Why should it be any different with humans and language? We are not surprised to find that other animals are specifically built to do the special things they do, why should humans be any different?
Third, the alternative, that all learning relies on general purpose mechanisms, is as coherent as the idea that all perception relies on a general purpose sensing mechanism. Just as seeing involves mental mechanisms and cognitive apparatus different from hearing or smelling or touching or tasting so too learning language is different from learning faces or learning to recognize objects or fixing causal interactions. Gallistel and King (in Memory and the Computational Brain: 221) make the point well:
…a very general truth about learning mechanisms [is] they do not learn universal truths. The relevant universal truths are built into the structure of a learning mechanism. Indeed, absent some built-in relevant universal truths and the strong constraints they place on the form of the representation that can be extracted from a given experience, learning would not be possible.
As linguistic representations from all that we currently know are formally quite different from other cognitive objects it would be surprising if their peculiar properties did not require some built in language specific mental mechanisms to allow for their acquisition and use, just as in the case of honey-bees and ants with respect to navigation.
Many resist these conclusions about UG. The idea that UG involves at least one linguistic specific feature is considered particularly controversial. But for the general reasons noted above, I can’t see why anyone would assume anything different. This judgment is reinforced once one takes a look at the linguistic competence humans have in more detail. Linguistic objects are very distinctive. UG must be able to accommodate these distinctive properties. If this means that UG invokes special cognitive powers, we should not be in the least surprised, nor perturbed. That’s the way biology works.