ABSTRACT
As mentioned previously, the late 1960s saw a revival of the classical view that a reaction process may consist of a sequence of processing stages. It was realized that Donders’ (1868) hypothesis had never been subjected to a serious experimental test. Most importantly, Sternberg (1969) launched a completely new approach to the issue, that is, the additive factors method (AFM), which differed considerably from Donders’ stage insertion and which became a highly influential, albeit not undebated, technique.
