The prevailing view among researchers looking at early language acquisition has been that young children learn words by what is essentially a trial and error approach. In this view, children hear numerous words and see many objects. Over time, hearing particular words associated with particular objects, they narrow down the names for specific objects until they learn the correct word. The problem with this approach, according to a research team at the University of Pennsylvania, is that it is most often studied in a laboratory situation, where young children are shown objects in a controlled setting. They posit that if you look at this scenario in the real world, filled with lots of distractions, innumerable objects, and confusing terminology for most objects (how can a big blue cup with a handle have the same name as a small yellow cup without a handle?) it becomes impossible for the human brain to sort through and narrow the almost infinite input around us, and that the currently accepted theory of how children learn words does not hold up.
To study this issue further, these scientists developed three experiments, each involving videos of children and their parents. In the videos, specific words (or a single word) were targeted, but the study subjects (both adults and preschoolers) did not hear the targeted word, which was blocked by a beep or replaced by a nonsense word. The researchers also used context clues that were particularly informative or more general, and noted differences in how the subjects learned from the high and low context clues.
The scientists found that the subjects learned the targeted words in what they describe as a "eureka moment," with understanding not building gradually, but coming all of a sudden. They also noted that only the high context cues stayed with the subjects and helped them learn the targeted words. Once subjects started to guess incorrect meanings based on low context clues, they stayed on the wrong path but eventually forgot the incorrect guesses, which was necessary for the subjects to learn the correct meaning.
Certainly, this research is in its early stages, but it raises some interesting issues for further study about how children acquire language. It also raises questions about techniques such as flashcards for learning words, which seem to be less effective than real-world, context rich interactions.