| Abstract: | Human subjects have difficulty in generating sequences that satisfy accepted requirements for randomness. This is often attributed to faulty cognitive operations or concepts of randomness. This article explores the alternative possibility that these deficiencies result from the operation of the same basic mechanisms for selecting responses that are studied in psychophysics. The features of random generation are briefly reviewed, an experiment is reported, and a model for random number generation is presented. The model assumes that an internal analogue source produces a random variable which may be represented on an internal dimension, the aleatory decision axis. The subject uses the measures produced by this random generator to select discrete responses. The mechanisms that select these responses use decision criteria whose positions on a decision axis are determined in accordance with a theory of the setting and maintenance of criteria presented elsewhere (Treisman & Williams, 1984). It is shown that this model can explain some important features of random sequence generation, and that what may be described as "cognitive intrusions" can be distinguished from effects of the response selection system. (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
