Measuring change in motor memory

While research into the processes underlying motor memory has burgeoned in the past decade, issues as to what dependent measure(s) to use (i.e., AE, E, CE, or VE) have not been adequately resolved. Does one use a single (composite) meausre (i.e., AE or E) or its components (i.e., CE and VE)? If one decides to use a single measure, either AE or E, which is more appropriate? A cursory examination of the reported literature dealing with motor memory reveals a decided lack of cross-experimental consistency in the use of dependent measures that can only serve to impede a clear understanding of memory processes. It is argued here that in order to improve cross-experimental comparison and to facilitate a clearer understanding of what each of these measures mean in terms of memory processes all three (i.e., AE or E, CE, and VE) should be reported.