Finding with Frequencies (image) Brown University Caption Bats send out harmonic pairs of frequencies to sense where things are. The strength differences in the high and low frequencies in the pair (minimal in red, greater in blue) help the bat focus on the target front and center, according to research by Brown neuroscientist James Simmons. Credit James Simmons/Brown University Usage Restrictions with credit 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.