| The present study investigated the effect of pattern complexity on the perception of vibrotactile spatial patterns. Patterns were presented to a single finger and to separate fingers. As in previous studies, complexity was defined by the number of lines in a pattern (Craig & Evans, 1987; Evans, 1987a, 1987b; Evans & Craig, 1986). Unlike previous studies, however, sets of simple and complex patterns that were equally identifiable were used in several perceptual measures. The results indicated that the effect of complexity on perception is task specific, that is, whether complexity affects pattern perception depends on the measure.;Reaction times were similar for one- and two-line patterns presented in isolation to the fingerpad, suggesting that patterns were processed in parallel. In the presence of a temporal masking stimulus, two-line patterns were more difficult to identify than one-line patterns, but reaction times were similar. Similar reaction times, and the fact that there was more forward masking for two-line than one-line patterns, suggests that a backward masker does not limit the amount of time available for processing the target. Instead, the masker may have been integrated with an internal representation of the target (Craig & Evans, 1987; Evans, 1987a, 1987b; Evans & Craig, 1986).;One- and two-line patterns presented to a single finger were equally discriminable when pairs of different two-line patterns shared no lines in common. One-line patterns were more discriminable than two-line patterns when pairs of different two-line patterns shared a line in common.;When pairs of patterns were presented simultaneously to separate fingers, and subjects had to divide attention, discrimination and identification performances were lower for two-line than one-line patterns. Consistent with previous results (Craig, 1985b), performance improved when patterns were presented to separate fingers on opposite hands rather than the same hand.;The results are interpreted in terms of descriptive models of processing tactile spatial patterns, and the view that separate fingers may represent independent channels for inputting information. |
