The memory drum theory after twenty years: comments on Henry's note.

The difference between the Henry "memory-drum" theory and our version is that ours includes, an additional assumption that, after programming has occurred, the resultant representation can be stored in short-term memory. Otherwise, the essential ideas are the same in the two theories. Implications of the presently available data for the distinction between the theories are discussed. Regardless of how one evaluates our added assumption, it is clear that the essential insight of the Henry theory has fared very well in the 20 years since the theory first appeared in print.