Mean ratings of graphic distinctiveness were obtained for pairs of consonants. The comparisons were between uppercase forms of different consonants, lowercase forms of different consonants, and uppercase vs lowercase forms of the same consonants. The ratings were demonstrated to have satisfactory reliability and to covary moderately well with feature-component measures of letter-pair distinctiveness.The present study presents normative data for the gra phic distinctiveness of pairs of consonants. Specifically, ratings of graphic distinctiveness were obtained for all combinations of paired consonants in both their uppercase and lowercase forms, together with comparisons between the uppercase and lowercase forms of each consonant. The norms supplement Gibson's (1969) feature-component system of measuring letter-pair distinctiveness, a system based on the percentage of physical features shared by letters. However, Gibson's system is applicable only to uppercase comparisons. Moreover, gradations of distinctiveness are somewhat limited by the relatively few physical features employed.Letters obviously vary in the extent of their distinctiveness. Variation in distinctiveness, in turn, is likely to be related to performance on tasks requiring discriminations between letters, whether the letters occur as individual items or as elements of words serving as items. These tasks include letter identification (e.g., Thompson & Massaro, 1973), same-different letter judgments (e.g., Krueger, 1973), and recognition learning (e.g., Kausler & Pavur, in press), and they in vo Ive discriminations between both nominally different letters (e.g., B vs P) and nominally identical letters (e.g., B vs b). The present norms should facilitate such research by extending the material available for selecting consonant pairs of differential distinctiveness.
METHOD Subjects and DesignThe Ss were 114 students in undergraduate psychology courses, primarily general psychology. Each S rated 210 letter-pair comparisons for graphic distinctiveness-the 20 uppercase-lowercase comparisons between nominally identical consonants (e. Test booklets were typed on an IBM 2741 communications terminal with a standard p.ica type ball. The use of only one typeface necessarily restricts the generalization of the present norms. However, it seems unlikely that the graphic content of the present set of consonants differs markedly from that of the consonants serving as task components in most research studies.The cover sheet of each test booklet contained instructions for rating each letter pair on a 9-point scale, with I indicating high dissimilarity of a pair's graphic content (i.e., high distinctiveness) and 9 indicating high similarity (i.e., low distinctiveness). The instructions were patterned after those employed by Zechmeister (1969) to measure the graphic distinctiveness of individual words. However, they were modified in accordance with the present task requirements. Examples of vowels varying in graphic distinctiveness were given for illustrative purposes. Tw...
