The relative sensitivities of heart rate and T-wave amplitude to stress: comments on, and some alternative interpretations of, Penzien et al.'s results.

Although the joint measurement of heart rate (HR) and T-wave amplitude (TWA) in experiments manipulating psychological processes is a sound and fruitful approach, Penzien Hursey, Kotses and Beazel's (1982) interpretation of their results may be questioned on two grounds: (a) Wether the process being manipulated between their groups was really the degree of stress; and (b) whether the degree of threat or aversiveness is really indexed more reliably by HR changes than by changes in TWA. This note questions these two assumptions, and also offers an alternative vagal interpretation of the Penzien et al. (1982) results.