The use of reaction time, N200 and P300 latency, movement time and accuracy data in localizing the effects of amphetamine and ethanol on stages of information processing and energetical mechanisms: Implications for uni- and multidimensional views of human

Variation in the magnitude of one or more energetical mechanisms (e.g., arousal, activation, effort) have been proposed as a possible explanation to account for changes in human performance. In the present study, arousal and activation were manipulated by administering amphetamine and ethanol either alone or in combination.;The Humphreys and Revelle (1984) unidimensional model was tested using two short-term memory (STM) tasks. It was found that amphetamine, but not ethanol, improved recall accuracy in the unattended ear using a dichotic listening task. Results of the STM tasks do not support Humphreys and Revelle's assumption that increases in arousal should lead to decreases in STM recall. Rather it is suggested that increases in arousal influenced an attentional component of cognition which aided recall.;Two multidimensional models, the Sanders (1983) cognitive-energetical model and the Fowler et al. (1985) gating model, both of which assume the Additive Factors Method, were tested and investigated the feature extraction, response selection and response execution stages of processing.;For the feature extraction stage, amphetamine decreased reaction time (RT) interactively and P300 latency additively, while ethanol increased RT and P300 latency additively. For the response selection stage, amphetamine decreased RT additively, while ethanol showed a trend for an additive slowing. For the response execution stage, amphetamine decreased movement time (MT) interactively, while ethanol increased MT in an additive manner.;While the results do not wholly support either of the multidimensional theories entirely, there is more support for the Fowler et al. gating model. However the issue is raised of whether even multidimensional models of arousal are capable of fully explaining drug effects.