Watch some wine-tasters contemplate their choice and you might think flavors take forever to register in the brain. In fact, humans can make taste-dependent decisions after as little as 50 milliseconds (50 thousandths of a second) of tasting, research at Cornell University is showing.

That's a good thing, says sensory physiologist Bruce P. Halpern, Ph.D. For a while it looked like even rats made up their minds faster than humans.

"Rats need only 125 milliseconds to make a taste-dependent decision, but for years it was thought that humans require 700 to 1,000 milliseconds," said Halpern, chair of the Cornell Department of Psychology and a professor of neurobiology and behavior. "Taste was always described as the 'unusually slow sensory system' in humans." Granted, rats have a life-or-death reason to make up their minds quickly about taste -- especially tastes that may be poison. Rats drink by rapid licking, and they can't vomit away their mistakes, Halpern explained. Humans are suction drinkers and can hold liquids in the mouth for several seconds before swallowing or spitting out. But could rats really be nearly 10 times faster at tasting? Halpern designed a series of experiments that eventually demonstrated that humans are both fast and flexible tasters. In one test, volunteers were asked to spit out a "target" flavor and swallow any others while throat microphones and lip electrodes measured events for computer analysis. The target flavor was reliably spit, even when -- a few minutes before -- it had not been the target flavor and had been consistently swallow instead.

"The spit test was never popular," he said. "Volunteers didn't mind, but lab assistants hated it." Now that the sensory physiologist has humans registering taste in the 50-milliseconds range, Halpern has moved on to more complex questions of interest not only to physiologists and psychologists but to the food-and-beverage industry. For example, how long does a taste sensation take to peak in intensity, change or disappear? Sweetener makers don't want the taste to rise too slowly or leave an aftertaste, he noted. But beer makers may want to provide a slowly increasing perception of bitterness.

His efforts at time-intensity tracking required redesigned experiments, and one, he said, "is similar to something that Cornell students apparently have a lot of experience with -- video games." Students use a joystick to draw pictures of changing taste intensities as they experience them. Another test, time-quality tracking, requires a little more training: learning keyboard codes for 24 taste descriptions, such as "fruity," "bouillon" and "yuck."

At Cornell, Halpern teaches Chemosensory Perception, Sensory Function, and Effects of Aging on Sensory and Perception Systems. Research in sensory physiology also has clinical applications, potentially improving the diagnosis and treatment of chemosensory (smell and taste) disorders, the scientist noted.