The Aztec skull whistle produces a piercing, scream-like sound. According to a study by the University of Zurich, this sound has a strong frightening effect on the human brain. It is assumed that the Aztecs used this effect specifically in their sacrificial rituals in order to influence the participants emotionally.
Musical instruments in Aztec rituals
Like many ancient cultures, the Aztecs also used musical instruments in their religious and ritual ceremonies. Their rich mythology was often represented by visual and acoustic elements that symbolized beings from the underworld. The skull-shaped skull pipe probably represented the ruler of the Aztec underworld and prepared the victims for the journey to Mictlan, the Aztec underworld, with its eerie sound.
The unique construction of the skull pipe
A team of researchers from the University of Zurich, led by Sascha Frühholz, Professor of Cognitive and Affective Neuroscience, reconstructed original Aztec skull pipes from the Ethnological Museum in Berlin using digital 3D models. These models revealed a special internal structure with two opposing sound chambers. This construction generates the distinctive, shrill sound through air turbulence.
Frühholz explains: "We know of no other musical instrument from pre-Columbian cultures or other historical contexts that resembles this construction method."
A frightening sound effect
Sound recordings of original and replica skull pipes were found to be extremely frightening by test subjects. Many listeners described the sound as human, comparable to a scream. The whistle seems to deliberately imitate sounds that humans instinctively perceive as threatening.
"This corresponds to the tradition of many ancient cultures of imitating natural sounds in musical instruments to recreate mythological creatures," explains Frühholz.
How the brain reacts to the sound
The researchers played the sound of the skull whistle to test subjects and recorded their brain activity. Brain regions responsible for emotional and affective reactions reacted particularly strongly. This confirmed the frightening nature of the sound. At the same time, the brain also showed activity in areas that process sounds with symbolic meaning. This indicates that the sound of the skull whistle not only triggers emotions, but is also interpreted as a cultural symbol.
The role of music in rituals
Music has always had a strong emotional effect on people - in ancient cultures as well as today. This is why it was often used in ritual, religious and mythological contexts. The Aztecs probably used the terrifying and symbolic sound of the skull pipe to influence the audience of their rituals emotionally and mentally.
"Of course, we couldn’t carry out our psychological and neuroscientific experiments on people from the Aztec period," adds Frühholz. "But the basic emotional reactions to frightening noises are common to all people across historical contexts."
Acoustic samples: https://caneuro.github.io/blog/2024/study-skullwhistle/
Literature
Frühholz S, Rodriguez P, Bonard M, Steiner F, Bobin M (2024), Psychoacoustic and archeoacoustic nature of ancient Aztec skull whistles. Communications Psychology. November 11, 2024. DOI: https://doi.org/10.1038/s44271’024 -00157-7
