On a daily basis, infants and toddlers encounter a plethora of items ranging from animals to appliances their parents use. Despite their limited abilities to process information, even very young children are remarkably capable of learning the names of these objects. Ellen M. Markman conducted some of the pioneering research on the reasoning skills that infants and young children use to figure out the meanings of words. When someone points to an object and labels it, how do children conclude the label refers to the object itself, rather than its color, size, shape, texture, activity, attractiveness, and so on? Markman has postulated that by the time children begin to acquire their vocabulary, they have a set of default assumptions that together enable children to quickly zoom in on some hypotheses and rule out others. Through extensive experimental research, Markman has challenged the traditional theories of word learning and provided new insights into the nature of language acquisition.