Lack of an order effect in brief contact taste tests with closely spaced test trials.

The number of licks during 30-s exposures to a range of concentrations of sucrose, glucose, fructose, maltose, and Polycose were recorded. A complete series of concentrations of each carbohydrate was offered in ascending, descending, or random order with 30-s intertrial intervals. The order of presentation differed on different days. For sucrose, glucose, fructose, and maltose the number of licks in the 30-s periods was an increasing monotonic function of concentration regardless of the order of stimulus presentation. For Polycose, the lick rate-concentration function was an inverted U-shaped function of concentration with a peak on the 0.1 M to 0.2 M range. In all cases the rate of licking declined during the 30-s exposure period, suggesting the development of gustatory sensory adaptation. The results indicate that it is possible to obtain a rapid assessment of the taste sensitivity of the rat to a variety of carbohydrate solutions on a single day with very brief intertrial intervals.