The independence of the P300 and the CNV reviewed: a reply to Wastell.

The relationship of P300 to the CNV was investigated by Donchin, Tueting, Ritter, Kutas and Heffley (1975) who concluded that these two components of the event-related brain potential (ERP) are independent. Wastell (1979) questioned the validity of the data analysis procedures and of the experimental design used by Donchin et al. In this report we examine Wastell's criticisms and find them to be unfounded. In support of this conclusion we note the differences between principal component analysis and factor analysis. We clarify points about Donchin et al.'s experimental design, and we review evidence for the independence of the P300 and the CNV that has accumulated since 1975.