What are the natural constraints for the human body representation? Here I report a perceptual illusion where healthy individuals experience having two right arms, with both sensing touches applied to them. This effect reveals how visual and tactile signals from the body are integrated in a probabilistic fashion, resulting in a single limb being represented at two locations at the same time, giving rise to a perceptual duplication of this limb. This is an important observation because it suggests that even the gross morphology that we experience of ourselves is a construct resulting from dynamic and integrative processes in the perceptual systems.
Get full access to this article
View all access options for this article.
References
1.
ArmelK CRamachandranV S, 2003“Projecting sensations to external objects: evidence from skin conductance response”Proceedings of Biological Science2701499–1506
2.
BenedettiF, 1985“Processing of tactile information with crossed fingers”Journal of Experimental Psychology: Human Perception and Performance4517–525
3.
BotvinickMCohenJ, 1998“Rubber hands ‘feel’ touch that eyes see”Nature391756
4.
BruggerPKolliasS SMüriR MCrelierGHepp-ReymondM CRegardM, 2000“Beyond re-membering: phantom sensations of congenitally absent limbs”Proceedings of the National Academy of Sciences of the USA976167–6172
5.
CaskeB, 1977“Perception of impossible limb positions induced by tendon vibration”Science19671–73
6.
DeneveSPougetA, 2004“Bayesian multisensory integration and cross-modal spatial links”Journal of Physiology, Paris98249–258
7.
EhrssonH HSpenceCPassinghamR E, 2004“That's my hand! Activity in premotor cortex reflects feeling of ownership of a limb”Science305875–877
8.
GrazianoM S AHuX TGrossC G T, 1997“Visuospatial properties of ventral premotor cortex”Journal of Neurophysiology772268–2292
9.
LacknerJ R, 1988“Some proprioceptive influences on the perceptual representation of body shape and orientation”Brain111281–297
10.
MaW JBeckJ MLathamP EPougetA, 2006“Bayesian inference with probabilistic population codes”Nature Neuroscience91432–1438
11.
MelzackR, 1990“Phantom limbs and the concept of a neuromatrix”Trends of Neurosciences1388–92
12.
WelchR BWarrenD H, 1986“Intersensory interactions”, in Handbook of Perception and Human Performance Eds KaufmanLThomasJ P (New York: Wiley-Interscience)
