S.B. after more than fifty years of blindness regained his eyesight. When he recognised simple shapes and ordinary objects as well as their size by vision, he was helped by his tactile memories. Indeed, memories based on one sense influence the perception of another. (See our blog for the scientific approach and the crossmodal correspondences between the senses.)
S.B. matched his new visual information to his memories, stored when he was still blind. When vision is absent, memories about simple shapes and ordinary objects, including size, are based mainly on tactile and auditory information.
Vision perceives a lot of different information simultaneously and it fills in any missing information. It starts with an overview and, then, focuses on details. Visual attention is drawn to colours that stand out from the background, sudden movements, and any changes. Vision perceives information about colour, location, movement, quantity, shape, size, and texture.
Haptic touch – the combination of touch and movement – perceives information serially, piece by piece by piece. It starts with the details and, then, builds up an understanding of the whole information (e.g., a picture, illustration, or scene). Attention seems to be drawn to differences in surfaces and textures. Haptic touch perceives information about hardness, location, movement, quantity, shape, size, texture, and weight1.
Hearing perceives a lot of different information simultaneously. It starts with an overview and, then, focuses on details. Auditory attention is drawn to sudden sounds that stand out from the background. Hearing perceives information about location, movement, quantity, shape, size, sound, and texture.
Vision, haptic touch, and hearing perceive much of the same information, but S.B. was still not able to recognise visual information that he had not experienced by haptic touch, hearing, or both.
Very little information is perceived by merely one of the senses: colour by vision, hardness and weight by haptic touch, and sound by hearing. And correspondences exist between this sensory-specific information, for example, hue and pitch (or timbre). Shape is an example of information that is perceived by all three senses. It transfers between them, and when they work together all sensory information is integrated to form or retrieve memories of it.
Only when the visual information matched well with his memories, based mainly on tactile and auditory information, did S.B. recognise the world around him. It seems the match is best with information that is perceived by two (or all) senses: S.B. recognised simple shapes and ordinary objects as well as their size.
The brain adapts rapidly when using a different sense, but it needs time to permanently change how it processes the perceived information. During this phase, it would be beneficial to use the senses for perceiving information that they are naturally attentive to and therefore familiar with already, for example, texture for haptic touch. Research has found that it also helps to focus on information that transfers between the senses, for example, shape. Both would serve as warm-up activities for the brain, preparing it for more complex information to come, such as traffic. To hear a series of favourite city soundscapes, please listen to “The Oxford Sound Album“.
See our blog Activities; especially 10-12.
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1The sense of touch, without movement, perceives information about temperature, pain, and pleasure.
