Exhaustive additivity suggests a new stage not an alternative model: A commentary on Fowler, Hofer and Lipitkas

Comments on the article by B. Fowler et al (see record 2000-15213-005) in which they observed that nitrous oxide, an inhalation anaethetic, does not interact with experimental manipulations derived from the additive factors literature. They proposed a 2-tiered cognitive-energetical model to account for the apparent "exhaustive additivity." This model assumes that nitrous oxide affects a lower tier resulting in a non-selective effect on an upper tier, which is comprised of energetic mechanisms that are selectively linked to processing stages. In this commentary, it is argued that the "exhaustive additivity" can easily be accommodated by linear stage models. The findings of Fowler et al suggest a new stage rather than a new model. Moreover, their new model seems to predict "exhaustive interaction" rather than "exhaustive additivity." It is concluded that Fowler et al may have a highly interesting finding, but not for the reasons they submitted when accounting for the "exhaustive additivity" displayed by nitrous oxide. (PsycINFO Database Record (c) 2000 APA, all rights reserved)