Media Naturalness Theory - Speech Importance

Speech Importance

Complex speech was enabled by the evolution of a larynx located relatively low in the neck, which considerably increased the variety of sounds that our species could generate; this is actually one of the most important landmarks in the evolution of the human species. However, that adaptive design also significantly increased our ancestors’ chances of choking on ingested food and liquids, and suffering from aerodigestive tract diseases such as gastroesophageal reflux. This leads to an interesting conclusion, which is that complex speech must have been particularly important for effective communication in our evolutionary past, otherwise the related evolutionary costs would prevent it from evolving through natural selection. This argument is similar to that made by Amotz Zahavi in connection with evolutionary handicaps. If a trait evolves to improve the effectiveness in connection with a task, in spite of imposing a survival handicap, then the trait should be a particularly strong determinant of the performance in the task to offset the survival cost it imposes.

Media naturalness theory builds on this evolutionary handicap conclusion to predict that the degree to which an electronic communication medium supports an individual’s ability to convey and listen to speech is particularly significant in defining its naturalness. Media naturalness theory predicts, through its speech imperative proposition, that speech enablement influences naturalness significantly more than a medium’s degree of support for the use of facial expressions and body language. This prediction is consistent with past research showing that removing speech from an electronic communication medium significantly increases the perceived mental effort associated with using the medium to perform knowledge-intensive tasks. According to this prediction, a medium such as audio conferencing is relatively close to the face-to-face medium in terms of naturalness (see Figure 2).