Psychophysics measures the attributes of perceptual experience. The question of whether some of these attributes should be interpreted as more fundamental, or “real,” than others has been answered differently throughout its history. The operationism of Stevens and Boring answers “no,” reacting to the perceived vacuity of earlier debates about fundamentality. The subsequent rise of multidimensional scaling (MDS) implicitly answers “yes” in its insistence that psychophysical data be represented in spaces of low dimensionality. I argue the return of fundamentality follows from (...) a trend toward increasing epistemic humility. Operationism exhibited a kind of hubris in the constitutive role it assigned to the experimenter’s presuppositions that is abandoned by the algorithmic methods of MDS. This broad epistemic trend is illustrated by following the trajectory of research on a particular candidate attribute: tonal volume. (shrink)

In the context of psychiatric diagnosis, operationists claim that mental disorders are nothing more than the satisfying of objective diagnostic criteria, whereas realists claim that mental disorders are latent entities that are detected by applying those criteria. The implications of this distinction are substantial in actual clinical situations, such as in the co-occurrence of disorders that may interfere with one another's detection, or when patients falsify their symptoms. Realist and operationist conceptions of diagnosis may lead to different clinical decisions in (...) these situations, affecting treatment efficacy and ultimate patient outcomes. (shrink)

With S.S. Stevens, operationism became an important influence in psychology. In this paper I discuss the differences between Bridgman's and Stevens' proposals on operationism and the role that operational definitions play in scientific theory. I discuss how Stevens' notions of the basic act of discrimination and of the relation procedure–outcome influenced B.F. Skinner's criteria under which the main conceptual distinctions in operant psychology were formulated. The operational origin of the dichotomies between respondent and operant behavior, contingency-shaped and rulegoverned behavior, private (...) and public events, and verbal and nonverbal behavior are examined. (shrink)