LAUSR

Significance More than 100 years ago, Etienne Lombard discovered that humans increase their vocal amplitude when exposed to ambient noise. Since then, the Lombard effect has gathered a plethora of interest from various disciplines ranging from linguistics to zoology. One unresolved question is in regard to the evolutionary origin of the Lombard effect, because it has been found in birds, mammals, and fish, but not in reptiles, and in amphibians the evidence is disputed. Using a phylogenetically controlled meta-analysis, we show that the Lombard effect is a widespread mechanism in vertebrates, and that amplitude adjustments require neither complex cortical processes nor vocal learning.