Investigating The Effect Of Sentence-Level Syntactic Structure On Information Loss In The Human Auditory System

Sentence-level syntactic structure, or syntax, refers to the principles by which grammatically correct sentences are formed. In this paper, we investigate the impact of the absence of syntax on human auditory recognition performance. Specifically, we analyse the word recognition accuracy of human participants listening to short segments of Danish speech-in-noise, with and without syntax. In sufficiently noise-free conditions, information about a spoken word is transmitted to the brain, allowing near-perfect decoding, whereas noise induces information loss. To quantify the information loss, we compute the difference in mutual information between the transmitted and decoded information for speech material with and without syntax, leveraging the data processing inequality applied to a Markov chain representing the communication model comprising the speaker, the noisy channel, and the listener. Our results indicate that the absence of syntax accounts for a loss of up to approximately one-third of the total transmitted information, elucidating the importance of syntax in facilitating effective speech processing.