Lower Fluency Image (IMAGE) University of Rochester Caption Researchers manipulated the fluency of the images, first making them easier to see by increasing the contrast (the black image), then making them less fluent by decreasing the contrast (the grey image). The monkeys were more likely to place a high bet, meaning they were more confident that they knew the answer, when the contrast of the images was increased. Credit Jessica Cantlon and Stephen Ferrigno/University of Rochester Usage Restrictions None 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.