Verbal learning: Incremental vs. all-or-none theory

The incremental and all-or-none theories of verbal learning are compared by means of a little-used but methodologically superior variation of the “drop-out” paradigm with paired associates. Earlier experiments purporting to be relevant to the controversy are rejected as failing to offer a conclusive distinction between the two theories. The results presented here are taken to support the incremental theory. It is suggested that irregularities in the results of this and other experiments are caused by several intrusive factors, and a “dual-factor” hypothesis which was put forward to account for these irregularities is questioned on logical and methodological grounds.