Von Frey Hairs (IMAGE) Penn State Caption Researchers tested whether there was a relationship between oral touch sensitivity and the perception of particle size. They used a device called Von Frey Hairs to gauge whether participants could discriminate between different amounts of force applied to their tongues. Credit Nicole Etter / Penn State Usage Restrictions Non commercial use only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.