Wheel Engineering Challenge (IMAGE) University of Exeter Caption Artefacts such as bows and arrows do not necessarily prove our ancestors had sophisticated reasoning and understanding of how these tools worked, new research suggests. Credit University of Exeter Usage Restrictions This image may only be used with reports of this research 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.