Which of the following experiments would be an effective way to determine the distribution of touch receptors in the skin?

• A. Have a blindfolded student tell when a bristle placed lightly against the skin is felt.
• B. Have a blindfolded student identify which body part was touched.
• C. Have a student describe sensations while a light is shone.
• D. Have a student count blinks in response to touch.

Answer: (A)

Touch sensitivity varies across the skin because there are more or fewer touch receptors in different regions. To map where these receptors are concentrated, you want a direct measure of how easily a region detects a light touch, without visual cues. In this setup, a blindfolded person reports when a light bristle contacts the skin. Because the stimulus is mechanical and vision is blocked, the response reflects the local tactile sensitivity and thus the density of touch receptors there. Areas with high receptor density, like fingertips, will register the touch more readily than areas with fewer receptors, revealing a distribution pattern across the body. The other options don’t assess receptor distribution: identifying which body part was touched tests localization; describing sensations with a light targets vision rather than touch; counting blinks is a reflex and not about touch sensitivity.