Studies of visual short term memory have revealed that information that has not been explicitly reported during full report procedures can still be accessed when partial report procedures are used instead (e.g., Sperling, 1960). The aim of the present study was to investigate whether tactile information is also initially retained in a short-term store. In Experiment 1, participants reported the total number of tactile stimuli (up to 6) presented simultaneously to their fingertips (numerosity task). In another condition, after being presented with the tactile display, the participants had to detect whether or not the position indicated by a probe (visual or tactile) had previously contained a tactile stimulus (partial report task). Participants correctly reported up to 3 stimuli in the numerosity judgment task but their performance was far better in the partial report task: Up to 6 stimuli were perceived at the shortest target-probe intervals. This result demonstrates that although tactile information may be unavailable for report in a numerosity task it can nevertheless sometimes still be accessed using a partial report procedure instead. The fact that participants’ performance was similar no matter whether the probe was visual or tactile further suggests that the processes underlying the encoding of the tactile stimuli presented in parallel on the fingertips have multisensory components.
In Experiment 2, a similar pattern of results observed when participants performed a concurrent articulatory suppression task, thus suggested that the encoding of spatial positions was not linguistic in nature. The results of Experiment 3 revealed that performance in the partial report task was overall better for stimuli presented on the fingertips than for stimuli presented across the rest of the body surface. However, in neither condition did concurrent articulatory suppression have any effect on participants’ performance as compared with a silent condition. Thus, greater sensitivity on the fingertips than on the rest of the body surface would seem to involve greater STM capacity in the absence of any difference in encoding processes. Thus, consistent with the literature on visual STM (see Irwin & Andrew, 1996, for a review), the results of the study reported here suggest that the information from a tactile scene that is stored for later report or comparison is typically represented in an abstract non-modality specific code.

References
Irwin, D. E., & Andrew, R. V. (1996). Integration and accumulation of information across saccadic eye movements. In T. Inui & J. L. McClelland (Eds.), Attention and performance XVI: Information integration in perception and communication (pp. 125-155). Cambridge, MA: MIT Press.
Sperling, G. (1960). The information available in brief visual presentations. Psychological Monographs, 74, 1-29.