Hearing and listening are not the same. We may use the wording interchangeably, but in terms of underlying processes, the two differ. Listening is defined as hearing with intention and attention (Kiessling et al., 2003). Listening thus involves both auditory and cognitive processing. Therefore, mechanisms such as attention, working memory and speed of processing are relevant themes when exploring the topic of listening. Listening begins peripherally, but it actually involves a mosaic of different cognitive functions working together in order to achieve fast and efficient perception of sounds. This ensemble of cognitive functions is called the listening connectome (Fig. 1, Kral et al., 2016).
Listening effort can be described as mental exertion required to attend to and understand an acoustic input.
The diagram below explains two different pathways how we understand acoustic inputs
First, in a quiet environment, the auditory signal is clear and can easily be recognized and understood. This is a fast process that requires low cognitive effort.
Second is in a more difficult , complex situations( or when the hearing threshold gets worse). Auditory signal is degraded and is difficult to recognize. Instead of instant recognition, the distorted input signal is compared to already stored information in the memory before understanding is possible. This requires a lot of effort and leads to fatigue.
Everyone has finite amount of cognitive resources. Cognitive resources can be used to compensate for the hearing difficulties. The greater the hearing problem, the more effort is required to listen and understand, hence feels fatigued quicker.