Apparent increase in lip size is linked to tactile discrimination improvement

Abstract

Magnified vision of ones body part has been shown to improve tactile acuity. We used an anesthetic cream (AC) to explore this effect. In Experiment 1, application of AC caused an increase in perceived lip size. As perceived lip size increased, tactile discrimination (as assessed by two-point discrimination) improved. In Experiment 2, we replicated these results in a larger sample and showed that these effects are not observed without AC. Tactile discrimination was better and improved as a function of lip size with AC, while performance remained consistent without AC. In Experiment 3, we showed that the increase in perceived lip size occurred only with the application of AC, but not with moisturizing cream. The application of either cream induced an improvement in two-point discrimination, but this improvement was modulated by perceived lip size only for AC. Magnification effects are mediated by malleable, experience-dependent representations of the human body.