SKILL AND CHANCE: VARIATIONS IN ESTIMATES OF SKILL WITH AN INCREASING ELEMENT OF CHANCE

Abstract

Experiments with three groups of subjects, ranging in age from 13 to 20 years, were carried out to determine how estimates of success in performance are influenced by (a) varying the subjective assessment of the degree of skill required to succeed in a task, and (b) varying the degree of subjective chance. The findings were as follows, (i) The result of introducing an element of subjective chance into a task requiring some skill is to make the estimates of success in the task progressively reflect the element of subjective chance as it increases in magnitude. (ii) This effect occurs regardless of the degree of skill subjectively felt to be required for the task. (iii) The values of subjective probability of success in performance given by the older subjects are not significantly different from the products of their corresponding values of ψ (skill) and ψ (chance). In the circumstances of these experiments, therefore, the subjective probabilities based upon the subjects' estimates are equivalent to those which the experimenter could independently arrive at if he only had available to him the values of ψ (skill) and ψ (chance) and had multiplied them. (iv) In the case of younger subjects aged 13–14 years, the subjective probabilities of success in performance are somewhat larger than the products of the two separate subjective probabilities. This may be due to a tendency on the part of younger persons to be more confident of success when their estimates relate to a single situation involving two sources of uncertainty as compared with when they relate to two separate situations, each involving its own source of uncertainty.