A new study of geladas – a species of monkey living in the highlands of Ethiopia – has revealed that their long and complex vocal sequences follow a pattern seen in many human languages: the longer the overall sequence, the shorter are the sounds within it. This work not only reveals similarities between our communication system and that of our primate relatives, it may also shed new light on the fundamental organisation of diverse biological systems.In human language, Menzerath’s law states that ‘the larger the whole, the smaller the parts’. So, for example, longer words tend to be made up of shorter syllables and longer phrases to be made up of shorter words…The findings of this work…not only reveal a basic pattern of sequence structure shared by human and non-human animal communication, but may also have profound implications for our understanding of biological systems more broadly.
…the authors of the study also provided formal mathematical support for the idea that Menzerath’s law reflects ‘compression’ – the principle from the field of information theory that relates to minimizing the expected length of a code. Compression provides a means of improving the efficiency of a coding system, and is applied (to save space or memory) in many man-made systems, such as digital images, videos and data storage. Compression also emerges spontaneously in human communication when space is constrained – Twitter being the prime example!
The researchers point out that, in addition to their own findings, patterns consistent with Menzerath’s law have already been found to hold at a range of biological levels – in genes, genomes and proteins. They propose, as a result, that compression may underpin biological information systems in a very broad sense – from molecules to animal behaviour to human language.