I'll present on a study we've been doing in collaboration with Nico Cesana-Arlotti and Justin Halberda on representations of collective and distributive actions.

We showed adults and infants movies in which chevrons chased moving balls. Adults spontaneously used the word “All” to describe movies depicting collectively-exhaustive chasing (e.g., 3 chevrons all pursued a single ball together), and “Each” for distributively-exhaustive chasing actions (3 chevrons each chased their own ball). Crucially, the use of “Each” significantly decreased when there were more than 3 chasing chevrons, suggesting that “Each” piggybacked on the representation of discrete individuals (within the capacity of working memory). Uses of "All" were not subject to this number-effect, suggesting that "All" piggybacked on the representations of groups (which have no set-size limit).

10-month-olds repeatedly exposed to the “All” movies regained attention when exposed to the “Each” movies and vice versa. These findings begin to suggest that the representations of collectively-exhaustive and distributively-exhaustive actions that connect with natural language quantifiers are in place long before learners acquire the meanings of words like "All" and "Each".