Cross-Modal Transfer

Methods

To test CM transfer, adults are asked to recognize by sight (or touch or sound) an object they previously experienced in a different modality. Another method involves training subjects on a task with one modality, then asking them to perform an analogous task in another modality. Performance on the second task is compared with that of subjects who had no training on the first task. Faster learning or better performance of the first group is attributed to CM transfer.

A method typically used with infants involves familiarizing them with a stimulus in one modality until they are habituated to it (no longer show interest), then presenting the same object in another modality paired with a new object. Infants show evidence of cross-modal transfer if they explore the new object longer, as they have already learned about the familiar object in the first modality.

Transfer between Vision and Touch

Although adults can transfer information from touch to vision and from vision to touch, there are situations in which they do not succeed, or are less accurate. For example, after holding an apple with closed eyes, an adult may be able to identify it when shown a visual array of differently shaped objects. Experimental factors that affect performance include length of exposure, object complexity, and stimulus properties (e.g., length versus shape). Another crucial factor is the degree to which vision and touch can derive the same information about a stimulus, known as perceptual equivalence, which depends on how strongly the stimulus characteristics are related across the senses. For example, if touch and vision were equally accurate at picking up an object's roughness, then roughness would be perceptually equivalent for touch and vision.

Shape

Overall, adults can visually recognize a shape (e.g., a cylinder or a prism) they previously felt and can identify by touch a shape they just saw. However, there is often an asymmetry, such that they are better at CM transfer from touch to vision than from vision to touch. Similarly, newborns can visually recognize a shape they previously felt, at least when they explored it with their right hands, but often fail to transfer the same shape information from vision to touch with either hand throughout the first year of life. The opposite asymmetry is found occasionally during development and depends on how different the test shapes are from [Page 338]one another, as well as the length of time subjects explore the objects.

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