The Stroop task has been used to examine the differences between automatic
and controlled (effortful) processing. Naming the color that the word is
written in is much more difficult in the second frame because of the automatic
process of reading. Reading makes color naming a more effortful process
(requiring intention and awareness, and interfering with other processes)
when the color and the word are incongruent. Some researchers are now using
the Stroop task as a measure of frontal lobe function.