On the nature of the perceptual speed factor

Werdelin, I. & Stjernberg, G. On the nature of the perceptual speed factor. Scand. J. Psychol., 1969, 10, 185–192.–149 subjects, about 15 years old, were given 25 psychological tests. Some of these defined the reference factors R, S, N, and P, others were designed to study the nature of the P factor. It was found that certain visual tests showed successively higher loadings in the P and N factors the more they were practiced. This effect of practice is probably restricted to tests of a certain kind. Very simple visual tests showed high loadings in the P factor. Hypotheses as to the nature of the P factor are suggested.