ABSTRACT
Experimental studies of individual differences have largely focused on differences in the slopes (exponents) of psychophysical functions. Although most studies indicate that individual differences in exponents are substantial and stable and tend to generalize across modalities, there are some conflicting results (see Gescheider , 1988). This chapter describes relationships among individual exponents for taste stimuli representing each of the four basic taste qualities , which were presented in a single session, as well as test-retest correlations among exponents for each taste in a subsample of subjects who were retested approximately a year later. In addition, however, an alternative analysis of individual scaling responses, which provides a measure of the reliability of repeated intensity judgments across a stimulus range .and , thus, of discriminative performance , is also presented . The relationship (or lack thereof) between differential sensitivity/resolving power and the steepness of the psychophysical function has provoked strenuous arguments (e .g., Stevens, 1961; Teghtsoonian , 1971). Therefore , a major focus of this chapter is an exploration of relationships between the extent
116 COWART
SUBJECTS
sample , as well as a reasonable cross-section of the adult life span. Of these subjects, 34 have been tested twice (see Table 9.2) ; the average interval between tests was 12 months (range = 3 months-24 months).
