Expertise in tactile pattern recognition.

This article explores expertise in tactile object recognition. In one study, participants were trained to differing degrees of accuracy on tactile identification of two-dimensional patterns. Recognition of these patterns, of inverted versions of these patterns, and of subparts of these patterns was then tested. The inversion effect (better recognition of upright than inverted patterns) and the part-whole effect (better recognition of the whole than a part pattern), traditionally considered signatures of visual expertise, were observed for tactile experts but not for novices. In a second study, participants were trained as visual or tactile experts and then tested in the trained and nontrained modalities. Whereas expertise effects were observed in the modality of training, cross-modal transfer was asymmetric; visual experts showed generalization to haptic recognition, but tactile experts did not show generalization to visual recognition. Tactile expertise is not obviously attributable to visual mediation and emerges from domain-general principles that operate independently of modality.