Choosing to interleave: human error and information access cost

People are prone to making more errors when multitasking. Thus in safety-critical environments, it is often considered safer to perform tasks sequentially. Here we explore how the cost of accessing information affects the way people choose to interleave. An empirical study based on a medical scenario was conducted. Participants had to program infusion pump devices using information from a prescription form. The physical and mental effort involved in accessing information was manipulated. This was achieved by varying the physical distance between the prescription form and the devices. We demonstrate that by increasing information access cost, individuals are less likely to omit a required task step. This is because they adopt a more memory-intensive strategy, which encourages interleaving at natural boundaries, i.e., after completing the programming of one of the pumps. Interleaving during programming can result in task steps being forgotten.