Associative learning has been meticulously studied in many species, and diverse effects have been explained using a handful of basic assumptions and mechanisms. Human language acquisition proceeds remarkably quickly and is of great interest, but is arguably more difficult to capture under the microscope. Nonetheless, empirical investigations have led researchers to theorize a variety of language learning principles and constraints. While there may indeed be language-specific learning mechanisms that are distinct from more universal associative learning mechanisms, we seek to explain some basic principles of language acquisition using domain-general mechanisms. Using an experiment and a model, we show how the principles of mutual exclusivity—an assumption of 1-to-1 word-object mappings, contrast, and other constraints related to fast mapping may stem from attention mechanisms attributed to associative learning effects such as blocking and highlighting, but directed by competing biases for familiar and unfamiliar pairs instead of surprise.