CALIBRATION CURVES, SCATTERPLOTS AND THE DISTINCTION BETWEEN GENERAL KNOWLEDGE AND PERCEPTUAL TASKS

Calibration curves and other methods of description and analysis (such as scatterplots and correlations) which derive from the individual di fferences tradition in psychology are examined in this article. Three tasks covering a range of cognitive ability were employed: the Raven's Progressive Matrices (RPM) test, a multiple choice synonyms Vocabular y test, and a perceptual test of Line Length. Scatterplots of accuracy and confidence ratings reveal that (a) the overconfidence that charac terizes Vocabulary tasks is due to a small number of items containing a ''familiar attractor'' alternative answer; (b) the RPM shows good ca libration; and (c) the underconfidence phenomena in the perceptual tas k is due to a tendency to ascribe essentially the same confidence rati ng to a number of items that differ in difficulty. The results of corr elational analyses support the view that there exists a trait of self- confidence that is separate from traits based on accuracy measures. Ov erall, males show a somewhat higher degree of self-confidence, Finally , practice has a negligible effect on confidence ratings.