T-wave amplitude: on the meaning of a psychophysiological index.

The preceding article by Furedy, Heslegrave and Scher presents a positive evaluation of T-wave amplitude (TWA) as a psychophysiologic index, and rejects the more cautious and less favorable view contained in a paper by Contrada et al. (1989). In this article I propose that the Furedy et al. perspective rests on: (1) a questionable approach to the logic of causal inference; (2) an unsatisfactory view of measurement validity; (3) the use of imprecise and therefore misleading language; (4) a disregard of valuable observations that can be drawn from the data of individual research subjects; (5) an objection to evaluative conclusions that can provide a useful stimulus to empirical inquiry. Close examination of these issues argues for a skeptical view of the state of knowledge regarding the meaning of TWA alterations.