Haptic recognition of two-dimensional raised-line patterns by early-blind, late-blind, and blindfolded sighted adults.

We investigated the role of visual experience and visual imagery in the processing of two-dimensional (2-D) tactile patterns. The performance of early-blind (EB), late-blind (LB), and blindfolded sighted (S) adults in the recognition of 2-D raised-line patterns was compared. We also examined whether recognition of 2-D tactile patterns depends on the type of memory strategy (eg spatial, visuo-spatial, verbal, and kinesthetic) used by EB, LB, and S participants to perform the task. Significant between-group differences in the recognition performance have not been found despite significant between-group differences in self-reported memory strategies. Recognition performance does not vary significantly with the strategy, but correlates positively with visuo-spatial imagery abilities in the S participants. These findings may be taken to suggest that the difficulties some blind people experience with tactile pictures are not due to difficulties in processing 2-D tactile patterns.