Methods for the quantification and statistical testing of ERP differences across conditions

Abstract

Several standard methods, as well as a new method for the quantification of event-related potential (ERP) differences across conditions, are described. The standard methods are (1) peak analysis, (2) the calculation of mean values, and (3) the calculation of difference waveshapes. The new method, called window analysis, was designed to quantify and statistically test in a very simple way any shape differences between two ERP curves in certain time intervals (windows) when clear peaks are lacking in one or all conditions. The window analysis is based on a conventional analysis of variance with sample time as an additional within-subjects factor. The significance of a shape difference between the curves for a factor of interest can then be determined with an F test for the interaction of this factor with the factor tune. The usefulness of the window analysis is demonstrated in an example with real data. Copyright 1998 Psychonomic Society, Inc.