Identification of scanned and static tactile patterns.

Most of the studies in which the interactions between target and nontarget spatial patterns have been examined have tested patterns that are generated statically. Static patterns are those in which all the elements of the pattern are presented at the same time and at a fixed location on the skin; however, most tactile information comes to the skin by means of patterns' being scanned across the surface of the skin. In the present study, the interactions between target and nontarget patterns were measured for patterns generated in both the static and the scanned modes. Nontarget patterns often interfere with the perception of target patterns. Using patterns generated in the static mode, previous studies have identified two factors that produce interference in pattern identification: response competition and masking. Masking, in turn, appears to be the result of temporal integration of the target and nontarget patterns, as well as the displacement of target features. In the present study, these factors were examined for patterns generated in both static and scanned modes. Regardless of the mode in which the patterns were generated, similar functions were obtained relating identification performance to the temporal separation between the target and the nontarget patterns. Although statically generated patterns are more easily identified than scanned patterns, particularly at brief durations, mechanisms such as response competition, temporal integration, and the displacement of target features appear to be factors that affect scanned patterns to nearly the same degree as static patterns.