An influential experiment conducted two decades ago by Dare Baldwin with infants aged 16-19 months began like this:
The experimenter produced a colored plastic bucket (rattling it until the infant looked at it), opened the bucket, removed the two novel toys, and placed them side by side on the table. She then placed one of the novel toys back inside the bucket, making certain that the infant watched her do this. Returning to the still-visible toy, she demonstrated what it could do, and then handed it over for the infant to explore. Then the experimenter grasped the bucket in both hands, while keeping it upright so that the infant was unable to see what was inside. She waited until the infant was looking at the visible toy (using the side-view mirror to make this judgment), looked down into the bucket, uttered a novel label (e.g., "It's a toma"), and maintained her gaze toward the bucket for 4 s [seconds].
(Baldwin, 1991)
What happens next?
If the participant is a typically developing child, he will look up at the adult, follow her eye gaze, and deduce that “toma” must refer to the toy in the bucket. Put another way, typically developing children typically use what’s called “Joint Attention” to learn the meaning of novel words.
Joint Attention combines attention to a person with attention to an item that is a potential object of shared interest. Person A attracts Person B’s attention (say, by commenting on something that they’re attending to). B responds by disengaging from what he’s doing and looking up at A’s face to see where A is looking. B’s eyes then follow A’s eyes to A’s object of attention. In one final step of social awareness or social reasoning, B then infers that A’s comment is probably about the thing that A is attending to.
Diminished Joint Attention pervades the diagnostic criteria and screening tools for autism and correlates tightly with autism severity. For example, one of the six “critical items” on the Modified Checklist for Autism in Infants and Toddlers, a preliminary screening tool for autism, is “If you point at a toy across the room, does your child look at it?”
Joint Attention also correlates tightly with word learning. If the child with the toy doesn’t look up and follow the speaker’s eyes upon hearing “It’s a toma”, she will miss out on an opportunity to learn what “toma” means. Worse yet, she may mis-learn the meaning of “toma”: she may assume that it refers to the toy in front of her rather than to the toy in front of the speaker. Indeed, that it precisely what Simon Baron-Cohen et al. found in their recreation of Dare Baldwin’s experiment with children on the autism spectrum. Only 29.4% of their autistic participants mapped the word to the correct toy.
Vocabulary size ranges across the autism spectrum; so does frequency of Joint Attention behavior. Numerous studies (see Adamson et. al.) suggest that how frequently a child engages in Joint Attention not only correlates with but is a causal factor in how much language he subsequently acquires.
Put all this together, and we have a clear explanation for the tight correlation between autism severity and language impairment.
What, then, about all that sophisticated vocabulary that comes out during facilitated communication? Facilitated individuals are generally diagnosed with severe autism and so, by diagnostic definition, rarely engage in the Joint Attention behaviors that enable word leaning. Yet somehow they are exceptions to all this: to the decline of language skills with autism severity; to the dependence of word learning on Joint Attention. Somehow, these FCed individuals, who have had few opportunities to learn even the basic words for objects in the immediate environment, already know words like “love” and “galaxy.”
As a linguist who studies language acquisition in autism, I am eagerly waiting for an explanation for how this is possible.
Adamson, L. B., Bakeman, R., Suma, K., & Robins, D. L. (2019). An expanded view of joint attention: Skill, engagement, and language in typical development and autism. Child Development, 90(1), e1–e18. https://doi.org/10.1111/cdev.12973
Baldwin D. A. (1991). Infants' contribution to the achievement of joint reference. Child development, 62(5), 875–890.
Baron-Cohen, S., Baldwin, D. A., & Crowson, M. (1997). Do children with autism use the speaker's direction of gaze strategy to crack the code of language?. Child development, 68(1), 48–57.
