| Abstract: | When subjects are requested to judge single stimuli the observableresponses are the result of both sensory and judgmental processes.De Graaf et al. (1987) employed functional measurement in combinationwith a two-stimulus procedure in order to separate these twotypes of processes. This paper discusses the results of twoexperiments investigating taste interactions in quinine HCl/NaClmixtures. The first experiment employed a one-stimulus procedure,the second experiment employed De Graaf et al.'s two-stimulusprocedure. Comparing the two procedures, the main advantageof the one-stimulus procedure seems to lie in its simplicity.In addition, it enables the determination of a scale value forwater. However, the obtained ratings are context-dependent andare affected by end effects of the response scale. The mostimportant benefit of the two-stimulus procedure is that it allowsfor a post-experimental verification of the linearity of theresponse-output function. This check ensures that all scalevalues are assessed on an interval scale. If water can be assumedto be tasteless, ratio scale values can be obtained. It wasshown that quinine bitterness is largely suppressed by NaCl,whilst the saltiness intensity elicited by NaCl remains virtuallyunaffected. In both experiments, the perceived total taste intensityof a mixture could be well predicted by the weighted sum ofthe saltiness and bitterness sensations within the mixture percept. |
