What a curious question! We can hear almost just as well with one ear as two so that is not the reason. Our glasses would fall off obviously though ears evolved long before glasses so that’s probably not the reason. Just in case we lose one ear by accident? That sounds reasonable but then why don’t we have a have a spare heart or spare brain too – they are more critical organs? Physiologists will explain that we need two ears to accurately determine the direction that a sound is coming from – and we do that by detecting very slight differences between what one ear hears compared with the other. What a neat bit of biodesign! So what relevance does this have for Improvement Science? Well, to improve a process or system we need to listen to two separate voices – the Voice of the Customer (VoC) and the Voice of the Process (VoP) – and if we compare them the slight difference points us in the direction of improvement. The problem is, when there is a big difference between the two sounds they will interfere with each other and we cannot hear either clearly. In that situation we adopt a policy of selective deafness – some of us choose the Voice of the Process because it can be measured objectively; and some of us choose the Voice of the Customer. The outcome is disagreement because we are hearing different things. Confusion becomes conflict.
With this insight one way out of this impasse might be for everyone to use both ears alternately: everyone listening to the Voice of the Customer for a while and then everyone changing channel and listening to the Voice of the Process for a while, and back again. The direction of improvement would become visible and the steps needed to align the Two Voices would emerge naturally. The Two Voices are trying to tell us something and we only need to learn to tune into both of them. When the Two Voices match we hear harmony not cacophony!