Multitasking is slowing you down
These experts have some basic advice. Check e-mail messages once an hour, at most. Listening to soothing background music while studying may improve concentration. But other distractions — most songs with lyrics, instant messaging, television shows — hamper performance. Driving while talking on a cellphone, even with a hands-free headset, is a bad idea. (...)
The human brain, with its hundred billion neurons and hundreds of trillions of synaptic connections, is a cognitive powerhouse in many ways. “But a core limitation is an inability to concentrate on two things at once.”
from NYT
See also The myth of multitasking