Spatial and temporal factors in the perception of ethanol irritation on the tongue

Abstract

The sensitivity of the tongue to the irritation produced by ethanol was measured in five experiments. It was discovered in the first two experiments that both latency to the onset of irritation and perceived intensity of irritation varied with the locus of lingual stimulation. The tonguetip and the side of the tongue were found to be more sensitive (that is, they tended to produce higher magnitude estimates and shorter response latencies) than sites toward the middle of the tongue, with the tonguetip being the most sensitive area tested. However, even on the tonguetip the latency to onset of irritation (approximately 2-6 sec) was much longer than typical values for taste sensation. The third experiment demonstrated that increasing the size of the ethanol stimulus resulted in shorter response latencies and more intense irritation. The latter result indicates that the sensory system responsible for ethanol irritation is capable of significant (but incomplete) spatial summation. The final two experiments showed that significant summation also occurs when stimulus area is increased by adding a second stimulus at another lingual locus. Possible explanations for the regional differences in sensitivity and for the relatively long onset latencies of chemical irritation are discussed. © 1988 Psychonomic Society, Inc.