Space-relevant tactile localizations may be influenced by non-tactile sources of information. This is evident in the fake hand effect wherein observers mislocalize tactile targets delivered to their unseen hand towards a visible fake hand that is positioned next to a pair of distractor lights. The aim of the present study was to use the fake hand effect to explore the factors that influence tactile localizations. First, the effect was quantified by comparing tactile localizations in the presence of the fake hand to those when the observer's hand instead occupied the normal fake hand location. The effect was quantitatively weaker than one would expect if the tactile targets were mislocalized to the locus of the fake hand (Experiment 1). Surprisingly, the fake hand effect did not depend on direct vision of the fake hand (Experiments 1 & 2), nor was it enhanced by tactile information that was congruent with the fake hand (Experiment 3). The effect, however, was sensitive to the consistency between the orientation of the fake hand and the observer's hand such that it disappeared when the two were inconsistent (Experiment 4). It was also sensitive to the mapping between the location of the digit stimulated and the type of foot response required (Experiment 5). These results have important implications for the flexibility of one's body schema.
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