Stop paying such close attention to what you're doing and you still might learn something¿even if you don't want to. That's the message from a study published today in the journal Nature.

The human brain quickly learns to perceive motion (not to mention shape and color), but scientists had thought that for these continual adjustments in perception to take place, people had to really concentrate on whatever was moving. Now Boston University psychologist Takeo Watanabe and colleagues have found that, at least in some cases, individuals can learn to perceive motion even when it's unrelated to what they're doing, they are distracted and they can't consciously detect it anyway.

In a series of experiments, Watanabe and fellows asked subjects to pay attention to letters flashing by on a computer screen while a group of dots danced discretely in the background. A few of the dots were sliding in one direction, but not so many that subjects noticed. When participants who received almost a month of such exposure were then tested with screens that featured enough dots travelling the same way to allow them to guess at the direction of motion, they were consistently better at judging which way the dots were headed than individuals who had not gone through the letter monitoring test.

Watanabe speculates that people might be able to exploit this power of the brain to learn the sounds of a foreign language by playing a language tape quietly in the background. He adds, however, that it's unclear whether individuals could acquire conceptual knowledge this way.

Although the new finding "does not deny the important role of attention in learning and in [perceiving] motion," the authors write, "it indicates that the adult brain has the flexibility to adapt to certain features of the environment as a result of mere exposure, even if the feature is so weak that it does not lead to awareness." Thus, they note, tuning out distractions may not always work, "which may be less adaptive in the context of our manipulative, modern-day media."¿JR Minkel

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