Introduction 1997 2003 2004 2000 1980 1993 2003 1 1933 1996 1997 Fig. 1 a b a h d c P V P C P V P C  The purpose of the present study was to obtain a better understanding of the representation of haptically perceived shape information, by probing the transfer of the curvature aftereffect. In the first experiment, we established the existence of an aftereffect when a curved surface is touched by a single finger and measured whether this aftereffect transferred to other fingers of the same hand. The second experiment was set up to determine whether the aftereffect depended on the finger used. Finally, in the third and fourth experiments, we investigated the transfer of the aftereffect between fingers of both hands. Materials and methods Subjects n  n  1993 Stimuli −1 −1 −1 1 Procedure A subject was seated behind a table. The preferred arm rested on a platform, which was 30 mm above the tabletop. In the third and fourth experiments, both arms rested on the platform. Only the fingertips projected over the platform. The experimenter placed the stimulus underneath a fingertip. A curtain prevented the subjects from seeing the stimulus. During a trial, the tip of one finger was placed on an adaptation stimulus for 10 s. Subsequently, the subject placed a finger on a test stimulus and had to judge whether this test stimulus felt convex or concave. Subjects were not allowed to move the finger over the stimulus surface, and the experimenter checked for this. No instructions were given on the force to contact the stimulus, nor was it measured. No feedback was provided on the response. Three conditions were measured in the first experiment. In all conditions, the adaptation stimulus was touched with the index finger. In one condition, the test stimulus was also touched with the index finger. In the other two conditions, the test stimulus was touched with the middle finger or the little finger of the same hand, respectively. Each condition consisted of 10 repetitions of a group of 18 trials (two adaptation stimuli × nine test stimuli) with trials randomized within a group. One complete condition was measured in a single session of about one and a half hours. The separate sessions were spread over different days. The order in which the conditions were conducted was counterbalanced for the first six subjects and randomly chosen for the last two subjects. In the second experiment, both the adaptation and the test stimuli were touched by the middle finger. In the third and fourth experiments, the adaptation stimulus was contacted by the index finger of the preferred hand; the test stimuli were touched with the index finger (third experiment) or middle finger (fourth experiment) of the non-preferred hand. Analysis 1 Results 2 Fig. 2 error bars  Experiment 1 t t 7 P  t 7 P  t 7 P  F 2,14 P  P  P  P  P Experiment 2 t t 7 P  2 t t 14 P  t 7.4 P  Experiment 3 t t 15 P  t t 22 P  Experiment 4 t t 7 P  Discussion 1996 1997 1996 2000 1997 2001 1997 2000 1983 1996 2000 2000 2000 2007 2000 2007 2000 2004 1996 1997 1997 This study shows that establishing the intramanual and intermanual transfer of the aftereffect is a useful tool in obtaining more insight into the representation of object properties as perceived by the fingers. In general, studying aftereffect transfer is attractive, because it enables a connection between psychophysics and neurophysiology. The convergence of these approaches leads to a better understanding of human perception.