Exhaustive additivity suggests a new stage not an alternative model: A commentary on Fowler, Hofer and Lipitkas (2000)

Fowler et al. (Fowler, B., Hofer, K., Lipitkas, J;, 2000. The exhaustive ad ditivity displayed by nitrous oxide has implications for cognitive-energeti cal theory. Biol. Psychol. 52, 161-180) observed that nitrous oxide (N2O, a n inhalation anaesthetic) does not interact with experimental manipulations derived from the additive factors literature. They proposed a two-tiered c ognitive-energetical model to account for the apparent 'exhaustive additivi ty'. This model assumes that N2O affects a lower tier resulting in a non-se lective effect on an upper tier, which is comprised of energetical mechanis ms that are selectively linked to processing stages. In this commentary, it is argued that the 'exhaustive additivity' can easily be accomodated by li near 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 i nteraction' rather than 'exhaustive additivity'. It is concluded that Fowle r et al. may have a highly interesting finding, but not for the reasons the y submitted when accounting for the 'exhaustive additivity' displayed by N2 O. (C) 2001 Elsevier Science B.V. All rights reserved.