Wednesday, April 20, 2016

Language Development Study at Harvard

Fig.1: Recruitment poster for study

Background: Last week, Junior and I participated in a Language Development Study. The study's goal: to check for the correlation between vocabulary and speed of learning new words. The study's subjects: babies ages 16 months to 2 years old, and their parental unit/s.

Methods: The study was divided into three parts: a game between the research assistant (RA) and the subject; the parent reading a story and teaching a new word to the subject; and the subject watching videos and identifying the correct object via voice prompts. The primary endpoint was the subject's ability to accurately learn new words.

Results: Junior learned the new words, but only after two or three errors.

Conclusions: We got a First 100 Words book out of the deal, so now he'll learn even more words! Also, a baby's having a large vocabulary (i.e. 30+ single words) may be predictive of the ability to quickly learn new words.


Junior has been contributing to science from a very young age. So far, he has been a very obliging control infant in a longitudinal allergy study at Healing Peanuts, Inc., and a grumpy and unwilling one for a baby MEG (magnetoencephalography) study, also at HPI. His latest adventure took him across the river, to my old stomping grounds of Harvard Square. This study promised to be more interactive, if less remunerative.

The Language Development Study is conducted by the Rowe Lab, which focuses on "the role of social interactions in children’s cognitive development, primarily language and literacy development from birth to age five." (source: Rowe Lab website) Their offices are large and equipped with child toys and furniture, and the RAs who worked with us were clearly very experienced at working with kids. I had to stop Junior several times from wandering off to follow one of the RAs or from checking out all the toys stashed in various offices.


Patient population

Babies ages 16-24 months are recruited for the study. They must be from households that speak English at least 50% of the time. 

Study Management

At the beginning of the study, parents complete a 10-minute questionnaire about demographic information, words known by their baby, and an intriguing set of questions about which quality they valued more in children (e.g. independence versus respect for elders, being considerate versus being well-behaved). During this time, the RAs establish rapport with the baby by pointing out objects in the room such as the animal stickers on the wall -- testing the subject's vocabulary in the process.

Then the study proper begins, composed of three parts. Part 1A consists of a game between an RA and the child. The RA hides a sticker under one of three different-colored cups, and the subject must choose the correct cup to retrieve the prize. In Part 1B, the RA literally adds another layer to the game by covering the cups in a scarf, then taking it off before asking the subject to select the right cup. Meanwhile, the other RA records the proceedings in another room.

During Part 2, the RA leaves after giving the parent a book with instructions to read it to the baby ("In English, please, so we understand," I was told), and to teach the little one a new word. It's a made-up word attached to a picture of Jigglypuff, although it would have been extremely entertaining to teach Junior how to say the Pokemon's actual name. I suspect "jee-puh" is what would have resulted.

Anyway, Part 2 takes 8 minutes, the book has no words so the parent has to explain the story on the fly, and the whole thing is also recorded.

In Part 3A, the dyad is taken to another room with a chair and a wall TV mounted with a webcam. The parent puts on shades so as not to lead the baby's gaze with his/her own. The baby, on the parent's lap, looks at the screen and is shown two objects. A voice prompts the baby to look at one of the objects, and accuracy is tracked using eye movements.

After 5 minutes of video, Part 3B begins. Both RAs come in to introduce two new objects to the subject using oddly-shaped stuffed toys. One is "Pimo" and the other is "Moku," and both come out of a box one at a time. After several repeated showings of each object, a long board with five stuffed toys velcroed to it -- including a Pimo and a Moku -- is shown to the subject, who is asked to pick out one of the new objects s/he has just been taught about, and to hand it to the RA. This continues until the baby consistently matches the object and the name.

Part 3C is the same as 3A, but with Pimo and Moku added to the video. This last part only takes 2 minutes.

Statistical Analysis



In Part 1A, Junior was able to find the sticker 2 times out of 4 (50%). In Part 1B, the sticker was also found twice during 4 attempts (50%).

In Part 2, Junior demonstrated his learning of the new word by speaking it after prompting from the RA.

Quantitative results for Parts 3A and C are unavailable at this time (since I had my eyes covered), but both RAs were very impressed by Junior's ability to sit still during the entire run of both videos.

For Part 3B, Junior was able to pick out Pimo and Moku after 2 failed attempts.


Junior came into the study with a large vocabulary, which I deduced from the initial questionnaire that asked me to check the boxes next to words he already knew. He was able to learn new words after a few errors, which seems indicative of a positive correlation between size of vocabulary and speed at learning new words.

More importantly, both RAs gushed that Junior was the absolute best participant they've had so far, and could he please come back, which morally obligated me to take some of their fliers and post it in my building to help their recruitment efforts.


This work was supported in part by the MBTA, which took us to the test site and this time did not subject us to elevators that smelled of pee.




TL;DR: Junior and I had a lot of fun at the Language Development Study!

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Summer Book Recommendations