Beverly Wright, first author of a study in the Sept. 22 Journal of Neuroscience and communication sciences and disorders professor at Northwestern [says] "Our work suggests that you can have the same gain in learning with substantially less pain." … [The findings] hold potential for members of the general population with an interest in enhancing perceptual abilities -- for musicians seeking to sharpen their sensitivity to sound, people studying a second language or physicians learning to tell the difference between regular and irregular heartbeats.People studying a second language, you say? So what is this learning sweet spot exactly?
Previous research showed that individuals become better at many perceptual tasks by performing them again and again, typically making the training tedious and long in length. It also showed that mere exposure to the perceptual stimuli used during practice on these tasks does not generate learning.Translation? We know that you'll learn something by doing it over and over again. We also know that just being exposed to something doesn't cause you to learn that thing. But a combination of a bit of practicing plus a bit of exposure causes you to learn something in 50% of the time practice alone would take.
But the Northwestern researchers found that robust learning occurred when they combined periods of practice that alone were too brief to cause learning with periods of mere exposure to perceptual stimuli. … What's more, they found that the combination led to perceptual learning gains that were equal to the learning gains made by participants who performed twice as much continuous task training (training which by nature of its repetition and length often is onerous).
Applied to language learning? This would mean that you're going to be swimming upstream if you try to learn a language solely by reading and listening (i.e., "mere exposure to the perceptual stimuli"). We know that something can certainly be learned by practice alone, but it's slow and inefficient (see, e.g., most language classes). But the most efficient way is a combination of both.
Forgive me if I'm just seeing my own opinions in these results, but this seems to argue for a language learning method in which you use both practicing (i.e., speaking and writing) and exposure (i.e., listening and reading) to maximize learning.
This would also explain how best to use spaced-repetition systems; as they are one kind of practice method, you'll need to follow up with exposure to maximize your learning.