S. S. Stevens’s Invariant Legacy: Scale Types and the Power Law

Abstract

Abstract S. S. Stevens was one of a number of prominent psychologists who published seminal articles in The American Journal of Psychology (AJP). Indeed, the first or, arguably, most important articles in several of his research strands were published there. In this brief treatment of his monumental work, I review these articles and some of their sequelae, both in Stevens’s own work and in that of others, in an attempt to sketch out how Stevens’s contributions in AJP helped form the development of experimental sensory and perceptual psychology throughout the 20th century. I focus on his work in psychophysical scaling, because in my opinion that has been his most important legacy. Indeed, the article that probably generated the flurry of work in psychophysical scaling that persisted into the 1990s was a brilliant work published in 1956 in AJP. In that article Stevens not only demonstrated the validity and reliability of direct scaling (in this case magnitude estimation and production) but also investigated a range of factors that could affect its results, anchoring the later work that led to its adoption as the fundamental and most popular approach to psychophysical scaling still in use today. In this section I also expand on a few of the modern directions in which this work has gone. Stevens also published in AJP classic articles on the localization of sound, the dimensions of sound, the relation of volume to intensity, and the neural quantum in pitch and loudness discrimination. He even contributed an article on scaling coffee odor. His work is a stellar example of how AJP has influenced psychological science then and now.