Brody, G., Feiman, R., & Aravind, A. (2024). Why Do Children Think Words Are Mutually Exclusive? Psychological Science, 35(12):1315-1324. doi: 10.1177/09567976241287732
idea is that children rely on an inductive bias that ensures that novel words get assigned distinct meanings from known
words—mutual exclusivity. Here, we explore the possibility that mutual-exclusivity phenomena do not reflect a bias
but rather information encoded in the message. Learners might effectively be told when (and when not) to assume
that word meanings are mutually exclusive. In three experiments (N = 106 from across the United States; ages 2 years,
0 months−2 years, 11 months), we show that 2-year-olds only assumed that novel words have distinct meanings if
the words were spoken with focus, an information-structural marker of contrast. Without focus, we found no mutual
exclusivity; novel words were understood to label familiar objects. These results provide a novel account of mutual
exclusivity and demonstrate an early emerging understanding of focus and information structure.