The Thought in the Dark Corridor

In a narrow stone corridor, in the dark, a deep note sounds. It seems to come from ahead, then from behind. A thought arrives at once: where is it? Then a second one: something is here. KTT counts both as thoughts, noticed or not, even when they arrive as a hair-raising feeling. The corridor is part of Chavín de Huántar, a ceremonial center in the Peruvian Andes that is about three thousand years old. Its builders left no readable writing. The sources read for this article are archaeological reports and summaries of acoustic research. They say what the building does to sound. They say nothing about what anyone thought.

What was found

In 2001, the archaeologist John Rick and his team found about twenty decorated trumpets made from large marine shells, called pututus, in a small gallery beside the site’s circular plaza. The shells came from a tropical sea species that had to be carried from far away. The researchers filed or cut a mouthpiece into each one, and found that they had been used.

What the building does to sound

Inside the site, below the platforms, run narrow stone-lined galleries with many right-angle turns and side alcoves. A team from Stanford, with Miriam Kolar and Jonathan Abel among them, measured how sound behaves there. Tones in the range of human voices and the shell trumpets produced consistent resonances in the alcoves. Two trumpets sounding together produced a beating effect, a warbling or throbbing that the researchers could reproduce with replicas. The short reverberation inside the galleries lets the trumpets work almost like percussion. One of Kolar’s questions was whether a listener inside the maze can tell where a sound comes from, or whether the architecture makes it seem to come from somewhere it does not. A visitor today can find the sound eerie, and Kolar reports feeling relaxed after hours of it.

What it cannot say

An acoustic effect is not a thought. What the people who walked these corridors felt, and what thoughts came, is not recorded. The reading that the site was built to shape perception is an interpretation that archaeologists present as supported by the sound evidence. It is not a measurement of anyone’s thinking.

What is not known

How the visitors of Chavín thought about what they heard is not known. No text survives.

Whether the effects were designed or are side effects of the architecture is not known either. Researchers treat the question as open.

Whether a modern listener’s experience resembles an ancient one is also open.