What is the rationale behind filler words? When we talk, we tend to use filler words like "ehm", "um", "uh", etc.
What is the rationale behind those constructs from a neurolinguistic point of view?
It seems this happens while we are thinking or searching for an answer to a question.
What is the rationale behind those constructs from a neurolinguistic point of view?


A simple conversation engages multiple areas of the brain, there are temporal areas for recognizing, planning &amp; generating speech, motor areas for executing it,Frontal &amp; PreFrontal areas for making sense of it,defining social context, and memory subsystems for holding both to small sound bites and longer conversational threads.

In my view,filler words are the speech equivalent of learned reflexes for movement or conditioned responses in the context of a conversation. Additionally, since we are also capable of overriding and co-opting such mechanisms, they can also be thrown in consciously (when stalling for time as you note) or avoided when public speaking by breaking cadence with silence.

From a neurolinguistics point of view, they most likely involve wernicke's area which is involved in the planning and selecting of words for speech ( along with recognition) and might involve PF-Temporal Areas trying to catch up in word and ideas selection or comprehension while maintaining cadence.

Source: Cognitive Neuroscience: The Biology of the Mind, ( The language chapter)