Tactile short-term memory revisited.

In each of three experiments subjects were required to point to the location of a discrete tactile stimulus applied to the underside of the forearm after delays of 10, 15, 20, & 30 seconds. Experiment 1 showed that recall accuracy was impaired independently by both concurrent articulatory suppression and increased delay between stimulation and recall. Experiment 2 compared two types of articulatory suppression task (repeating "the" continuously and counting backwards in threes) and showed that both exert the same effect on recall accuracy. Experiment 3 showed that, in comparison to a quiet condition, recall accuracy was impaired equally by: concurrent articulatory suppression; additional tactile interference; and both applied in combination. It is argued that articulatory suppression and tactile interference operate on separate mechanisms to impair recall accuracy for a tactile stimulus. In particular, tactile interference reduces the discriminability of the target tactile location, whereas articulatory suppression results in a depletion of central processing resources concerned with memorisation of the original location of the tactile stimulus. Such memorisation is not necessarily underpinned by an articulatory code.