What does the concept of "mutual exclusivity" aid in during language development?

The concept of "mutual exclusivity" plays a significant role in vocabulary expansion during language development. This cognitive bias suggests that children assume that different words refer to distinct objects or concepts; therefore, when they encounter a new word, they tend to assign it to an object that does not already have a known label. For instance, if a child knows the word "dog" and then hears a new word, they are likely to assume that the new word refers to something other than a dog. This helps children rapidly expand their vocabulary by enabling them to learn new words more efficiently, as they are actively categorizing and differentiating between objects, thus facilitating the acquisition of new vocabulary items in their growing lexicon.