Simon (1 of 2) (IMAGE) University of Exeter Caption To test the squirrels' intelligence and mental flexibility researchers invented a task involving a box with 12 sunken wells, four of which were hollow. Of the four, two contained hidden hazelnuts. Credit Pizza Ka Yee Chow Usage Restrictions Credit Pizza Ka Yee Chow 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.