Nurture vs. Nature: how does a growing brain limit learning?

Both the Berner and Stiller studies made me think about the process of language acquisition, and how cognitive development affects the process (as opposed to learning a language later in life, when your brain is not also developing). I spent a summer doing research on the difference in ability in making probabilistic predictions between typically developing children and children with Autism Spectrum Disorder. The experiments involved showing relative ratios of objects within a population and asking the child to make a prediction about a sample drawn from the whole population. Although this is different from the linguistic models discussed in the two papers, I wonder if there is some connection in how children understand not only scales for quantifying objects, but also in their ability to break large groups into subsets. If they are not able to “generate relevant alternatives for specific scales,” this suggests that they are not able to make predictions generalize based on their experience with multiple similar situations. This is the outcome that we saw in children with ASD, which is often characterized by cognitive delays, who would perform at chance (50% correct) when asked to predict whether a randomly selected hidden item was of the more numerous kind or the more rare kind.

This suggests that some of the linguistic errors in the Barner and Stiller studies may possibly be the result of not only the gradual acquisition of linguistic terms and proper use in children, but of the general, gradual cognitive development. These children may be failing to use “some” and “only”, not because they have not learned, but because they are incapable of learning. For example, Theory of Mind is a gradually acquired ability, allowing children to comprehend more aspects of another individual’s beliefs, thoughts, and perspectives. In the case of the Barner paper, the necessary implicature to understand “some” to mean “some but not all” requires not just the four steps outlined to go through the various linguistic possibilities. The inherent meaning of each possible statement must be comprehended, especially of the ones to members of the possible set, which requires a certain degree of theory of mind to understand the mental state that produced the statement and the intended meaning. In the case of ASD, children progress much slower up the ladder of Theory of Mind, even when they are capable of understanding and producing language, either verbally or through the use of technology.

I would be interested in how children with ASD who have a high degree of language comprehension, but not of Theory of Mind, would compare to the results in these studies, to test what degree of assumptions about an individual’s mental states is required in addition to linguistic parsing in order to arrive at the appropriate implicature. Thus, I propose that for the field of linguistics, acquisition and cognition must go hand in hand, studying the underlying mental abilities, as well as the outward manifestations of language use.