Journal of experimental psychology. Human perception and performance
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J Exp Psychol Hum Percept Perform · Apr 2014
Multiple spatial representations determine touch localization on the fingers.
Touch location can be specified in different anatomical and external reference frames. Temporal order judgments (TOJs) in touch are known to be sensitive to conflict between reference frames. To establish which coordinates are involved in localizing touch to a finger, participants performed TOJ on tactile stimuli to 2 out of 4 possible fingers. ⋯ Accordingly, we observed a benefit rather than impairment with finger crossing when both stimuli were applied to 1 hand. Complementary, participants systematically mislocalized touch to nonstimulated fingers of the targeted hand. The results indicate that touch localization for the fingers involves integration of several sources of spatial information: the anatomical location of the touched finger, its position in external space, the stimulated hand, and the hand to which the touch is (re)mapped in external space.
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J Exp Psychol Hum Percept Perform · Apr 2014
Can't touch this: the first-person perspective provides privileged access to predictions of sensory action outcomes.
Previous studies have shown that viewing others in pain activates cortical somatosensory processing areas and facilitates the detection of tactile targets. It has been suggested that such shared representations have evolved to enable us to better understand the actions and intentions of others. If this is the case, the effects of observing others in pain should be obtained from a range of viewing perspectives. ⋯ In the first-person perspective, a participant was faster to detect a tactile target delivered to their own hand when viewing painful grasping actions, compared with all nonpainful actions. However, this effect was not revealed in the third-person perspective. The combination of action and object information to predict the painful consequences of another person's actions when viewed from the first-person perspective, but not the third-person perspective, argues against a mechanism ostensibly evolved to understand the actions of others.