Researchers from the Wake Forest School of Medicine in North Carolina conducted an experiment on a group of male and female volunteers aged between 22 to 59 years. The volunteers were then rubbed with a cowhage, a plant with tiny hairs that irritate the skin, on the back, forearm and the ankle to produce an itching effect. The volunteers were prohibited from scratching the areas for five minutes.
The researchers then used as laboratory brush to scratch the affected areas themselves in order to produce as consistent technique on all the areas and recorded the reaction of the volunteers who were asked how pleasurable the sensation was.
The researchers found that scratching the ankle produced the highest intensity and the longest period of satisfaction while scratching the forearm produced a briefer and lower intensity pleasure sensation.
Commenting on the findings, one of the researchers who took part in the study, Professor Francis McGlone said, "It was interesting that the ankle was the itchiest site and that the most pleasure came from scratching it, because the back has been well-known as a preferred site for scratching."