Gustatory quality changes as a function of solution concentration

Four selected female Ss were instructed to respond with the qualities of either bitter, salty, sour, sweet, or no taste to solutions of LiCl, KCl, Li₂SO₄, or K₂SO₄ which varied in concentration from 0.0040 to 0.050 M for the first two salts, and 0.0020 to 0.025 F for the last two. Mean percentages of each quality, with sweet combined with the no taste response, when plotted against concentration, gave functions in which one quality predominated within a given concentration range. This quality was superseded by another over a higher concentration range. These results are explained in terms of an inhibition phenomenon.     

Stimulus generalization as a function of stimulus novelty and familiarity in rats

Three experiments used rats as subjects to investigate the generalization of conditioned responding between stimuli as a function of the subjects' exposure to these cues prior to conditioning. Experiment 1 used a between-subjects design, food as the reinforcer, and measured the tendency of subjects to approach the site of food delivery during the stimuli. Generalization of this response was more marked when the training and test stimuli were equated in terms of their novelty (i.e., when both were novel or both were familiar) than when the stimuli differed in this respect (i.e., when one was novel and the other was familiar). Experiments 2a and 2b used within-subjects designs to confirm the reliability of the results of Experiment 1. Implications of these results for current theories of stimulus representation are discussed.