It’s often quoted that if you have nothing nice to say, you shouldn’t say anything at all. Now, a new study from the hospital and Federal Institute of Technology (EPFL) in Lausanne has found that people respond better to positive words and sounds when they are heard through their left ear.

Humans react most to sounds from behind

To make the somewhat avant-garde discovery, scientists at the Swiss university analysed the cerebral responses of test participants. During the experiment, they would be played six different categories of sounds - from human vocalisations like erotic pleasure to frightened cries, applause, wind and a ticking time bomb - to see how their brains react when they are played through each ear.

Previous studies found that for unpleasant, powerful, exciting and intense sounds, humans react the most when they are moving towards the listener, especially from behind. A spokesperson for the EPFL told 20 Minuten that this likely has to do with our evolution, as we may be hardwired to read a sound behind us as the possible approach of a predator.

Positive sounds better received from the left, Swiss study finds

However, when it comes to different sides, Swiss scientists found that positive sounds were better received when they were projected from the participant's left-hand side. Subjects’ brains were less active when exposed to positive, neutral, negative and non-vocalisations when they came from the front, right or through surround sound.

Co-author of the study Tiffany Grisendi said that the experiments revealed that much of what we hear is vetted before it reaches the rest of our brain. "Our results suggest that the nature of a sound, its emotional valence and its spatial origin are first identified and processed [in our primary auditory areas]”, she noted. 

For Professor Stephanie Clarke, author of the original study, more research into the results is needed. “It is currently unclear whether the preference of the primary auditory cortex for positive human vocalisations on the left appears in the course of human development, and whether it is a unique situation or human characteristic. Once we understand this, we can speculate whether it is related to hand preference or asymmetrical arrangements of internal organs," she concluded.