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Trains now on Uber. T's and C's apply check the Uber app. This is a scientific American 60 Second Signs. I'm Jeff Dalvizio.

Today, part two of our three-part sound escape series to the Amazon Rainforest, and in this

episode we're going into the dark.

Make sure to catch the first episode on the mysterious Pink River dolphin after you listen to this one.

Again, joining us is Tim Weaver, a professor of emergent digital practices, and a multimedia and sound artist at the University of Denver.

Tim has traveled to the Amazon for years to collect what he calls the acoustic

planitude that's there. But before we listen to that planitude, let's talk about a

phenomenon with a strange name, the

Sharawaji effect. Tim, what is that exactly? The Sharawaji effect is

actually a approximation of the psychoacoustics that are happening.

Psychocoustics, that is the branch of psychology, concerned with the perception of

sound and its physiological effects. Thanks, Oxford Dictionary.

I mean, I liken it to acoustic hallucination.

What I've experienced is like, you know, here you're in the Amazon Basin

where all the drainage is going from the Andes down there and it's like the voices of the ancestors are speaking to you is what I've experienced but it may be composed of this incredible array of night choruses that are going on and it can happen in the day as well.

So it's like this polyphonic of mixtures emits new, and it's pretty profound.

Tim encountered one of those profound Sherwaji effect moments on the sound escape

he's taking us on today, and it came courtesy of a Riot of Ribbits.

In the Amazon there's an amazing diversity of amphibians and frogs of course are one of those

and the night is an amazing time to be wandering around provided you don't step on the wrong species.

...