A cup of coffee not only keeps people alert but also improves information processing abilities, says a new study.

Researchers from Tufts University found that caffeine enhanced performance in tasks that required information processing abilities like proof-reading.

"Coffee is the most widely used psycho-stimulant in the world," said Holly Taylor, a professor of psychology in the School of Arts and Sciences.

The study was based on two experiments that were conducted by Holly Taylor and colleagues. The first experiment involved 36 participants who drank half a cup of coffee a day. These people were given five minutes to read one page of news story and correct as many grammatical and spelling errors as they could find during that time. About 45 minutes before the test, the participants were given different doses of caffeine - either 0 milligram, 100 milligrams (equal to eight ounces of coffee), 200 milligrams (equal to 16 ounces of coffee) or 400 milligrams (equal to 20 ounces of coffee).

In the second experiment, researchers chose participants who drank more than three cups of coffee per day. Researchers found that caffeine improved peoples' performance in test and that these people were able to locate "complex global errors," like mistakes in subject and verb agreement and verb tense in the text.

One key difference was that people who were accustomed to drinking just half cup of coffee per day got better results with 200 milligrams (or about 16 ounces of coffee) of caffeine while heavy drinkers required 400 milligrams (about 20 ounces of coffee) to improve.

"These results support the notion that central nervous system stimulants may enhance global processing of language-based materials," the researchers wrote.

The study is published in the Journal of Experimental Psychology.