EUREKA!

EUREKA!

CAMPUS

[ NEW FINDINGS AND RESEARCH]

Mixed Signals

Call attracts mates, predators.

“Katydids are the potato chips of the rainforest,” says Laurel Symes, Adv’13, Neukom Fellow for computational interdisciplinary research. That’s because the ultrasonic mating calls of male katydids in Panama not only attract the attention of females, they’re also a clarion call to hungry bats. Together with Plannah ter Hofstede, assistant professor of biological sciences, Symes investigated how katydids successfully find mates while avoiding predators in the dense rainforest soundscape. The researchers spent weeks recording the ultrasonic chatter of the forest canopy using specially designed microphones, then slowed the recordings down to a frequency detectable by human ears for analysis. Their findings, published in Behavioral Ecology and Sociobiology, show that katydids have adapted a number of strategies to avoid predators, including calling less frequently during the night, going completely silent when a bat is near, or continuing to call from a safe location hidden beneath the leaves.

Eye to Eye

Pupils show engagement.

Pupil-dilation patterns may indicate the level of engagement between speakers and listeners, according to new research led by Thalia Wheatley, associate professor of psychological and brain sciences and principal investigator of the Dartmouth Social Intelligence Laboratory. Using infrared technology to track the eyes of listeners, Wheatley’s team found that collective pupillary synchrony was greatest during the emotional peaks of a speaker’s narrative. The study suggests that highly expressive individuals are more likely to keep an audiences’ attention. “ The eyes are the window to the soul’ is an ancient saying supported by many scientific studies linking pupil dilation and eye gaze to mental states such as attention and intention,” says Wheatley. “Plere we show that the eyes not only reveal the inner workings of one mind, but reveal when two minds connect.” The team’s findings are published in the Journal of Experimental Psychology.