Stone-Tipped and Wooden Spear Points (image) Arizona State University Caption Spears were carefully constructed to measure the same for the controlled experiments. Credit Jayne Wilkins, Benjamin Schoville, Kyle Brown. Usage Restrictions Must be used to illustrate coverage of this research only. 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.