Automation and mental workload: Why it is important to get the balance right

It is easy to assume that introducing automation into a task would decrease the mental workload on the operator – after all, if they are doing less, then the task must be easier. It also makes intuitive sense that an easier task should be performed more effectively. However, neither of these assumptions are necessarily true. Automation paradoxically has the potential to both increase and decrease mental workload, depending on the circumstances. Furthermore, decreasing workload can actually put an operator into an underload state, which is just as bad for performance as overload. We have learned these lessons in the aviation and, more recently, automotive industries; as accident reports demonstrate, we are now starting to see their impact on the railway with the introduction of Automatic Train Operation and other automated systems. The key in helping an operator to work at their best is to find a way to optimise their mental workload – which may mean thinking differently about automation.