Do Congenitally Blind Individuals have Better Haptic Object Perception Compared to Blindfolded Sighted Individuals?

Objective: Haptic perceptual enhancement in congenitally blind people is a subject of intense debate. There is no consensus whether the congenitally blind get the benefit of their haptic experience or the sighted get the benefit of previous visual experience when it comes to recognizing objects by manual exploration using different constraints. The present study compared haptic object perception between congenitally blind and blindfolded sighted participants in a situation where manual exploration of objects was constrained. Methods: Thirty congenitally blind braille readers and 30 age and gender matched controls were studied. All participants were required to identify the objects haptically, without the aid of vision. Manual exploration of the objects was constrained by permitting touching of the object with only the exposed tip of the index finger with the aim to limit cues about material information. Performance was evaluated in terms of speed and accuracy with which objects were identified. Result: The recognition time analysis showed that congenitally blind participants recognize objects much faster than blindfolded sighted participants. The analysis of haptic recognition rates showed that congenitally blind participants identified the objects more accurately compared to blindfolded normal sighted individuals. Conclusion: Congenitally blind individuals appear to possess a definite enhanced haptic perceptual ability allowing for faster and more accurate recognition of objects even when manual exploration is constrained.