While carrying out boring tasks, your mind does not wander - it simply disconnects - suggests a new study.
After scanning the brains of people carrying out repetitive tasks that led to lapses in concentration, the team led by Daniel Weissman of the University of Michigan, Ann Arbor, made the discovery.
To reach the conclusion, Weissman asked volunteers to spend an hour in a MRI brain scanner, identifying letters that flashed on a screen.
At times, their reactions slowed, showing that attention was wavering.
During these lapses, the scanner showed that activity between regions related to self-control, vision and language processing died down.
This is equivalent to these regions disconnecting altogether, said Weissman, rather than the brain simply wandering a little.
"Attention failed to grease the connections in the brain," quoted Weissman, who presented the results at a recent neuroscience meeting, as saying.
He said that attention is like a communication amplifier that only focuses on the connections between certain regions at certain times. When the amplifier switches to a new set of connections, existing ones weaken.
Communication between those regions slows and attention lapses.
The researchers also noticed one particular region "lit up" during lapses, and used this to predict when the mind would switch its focus.
"We're using brain signals to predict behaviour in the future," Weissman said.