Normal human adults judge two identical objects to have the same shape even when they are perceived through different modalities, such as touch and vision. The ontogenesis of man's capacity to recognise such intermodal matches has long been debated. One hypothesis is that humans begin life with independent sense modalities and that simultaneous tactual and visual exploration of shapes is needed to learn to correlate the separate tactual and visual sense impressions of them^1–3. A second hypothesis is that the detection of shape invariants across different modalities is a fundamental characteristic of man's perceptual–cognitive system, available without the need for learned correlations^4–7. Recent research has shown that 6–12-month-old infants can recognise certain tactual–visual matches^8–11. However, such data cannot help resolve the classic theoretical debate. Infants of this age repeatedly reach out …