On toddler vocabulary and categories

Picture this typical parent–child scenario:

A 2-year-old and his mom are walking through the grocery store together. As the parent puts food into the shopping cart, she labels some items that her child isn’t familiar with,  

{“Look, this is cauliflower. And, this is lettuce.”}

… while far more vegetables that she buys (like, green beans) go unlabeled because, quite frankly, it would be impossible for her to name every single new vegetable that they come across in the store. And, yet, her son learns what “cauliflower” and “lettuce” are, and that they’re both a vegetable. And, he also somehow (magically) develops an understanding of the far greater number of vegetables that went unlabeled during their shopping trip (including those green beans). How does this happen??? 

The authors of this study looked at whether infants and toddlers use what they refer to as “semi-supervised learning”. Basically, the idea is that the objects that are labeled for young children (in this case, cauliflower and lettuce) help them to develop an understanding of the category of those objects (vegetables). And, then they use what they know about that category to learn about the much larger number of items that go unlabeled (green beans) from that same category.


The results showed that two-year-olds only needed two items from a new category to be labeled for them to be able to identify other, unlabeled items from that same category. And, this was just as effective as providing labels for all of the objects (but, the children were unsuccessful when none of the items were labeled). 

There are two big take-aways from this study for those of us working with the birth to three population: First, it seems that less is more. In other words, it’s not necessary for us to label a million different objects to teach infants and toddlers a new category; in fact, just a few labels will do. The results also suggest that when we’re teaching vocabulary to infants and toddlers, the items that we do label should be clear representations of the category that they belong to so that they’re able to develop a strong understanding of that category.


LaTourrette, A. & Waxman, S. R. (2018). A little labeling goes a long way: Semi-supervised learning in infancy. Developmental Science. Advance online publication. doi: 10.1111/desc.12736