Electrodermal lability and the or: reply to o'gorman and further exposition of the “significance hypothesis”1

Bernstein's “significance hypothesis” and O'Gorman's recent challenge to it are reviewed. O'Gorman suggested that elicitation of an orienting response (OR) depended on systemic lability as indexed by frequency of nonspecific electrodermal fluctuations (NSF), without requiring mediation by central assessment of informational significance. Data are presented indicating that NSF itself also reflects central decisions about input significance—e.g., there was a differential rise in NSF during listening for a behaviorally signal under each of 3 different conditions, but not during presentation of the same physical stimulus lacking such significance. The relation between NSF and OR may reflect, in part, this common dependence. Systemic lability shown by NSF should not be considered a static characteristic, but a variable, centrally regulated function.