Dynamic change of degree of automation: the effects of decision role structure on performance under normal and failed conditions.

The industry is shifting from rigid systems towards dynamically adjustable architectures with flexible degrees of automation (DOA). A decision-role structure (DRS) defines how decision authority and responsibility for DOA adjustments are allocated between humans and machines. This study examined four DRSs, including human-only (HO), machine-only (MO), serial decision (SD) and parallel decision (PD) in simulated submarine track management tasks. The HO condition exhibited fewer DOA adjustments and prolonged high DOA, yielding better routine performance but poorer situation awareness (SA) and takeover performance. Participants tended to increase DOA under both SD and PD; downward requests were often rejected under SD and delegated to the machine under PD. The PD condition showed higher proportion of effective adjustments, higher SA and better takeover performance without compromising routine performance. The MO condition involved more manual operations and yielded suboptimal outcomes. Overall, the PD condition best balanced routine and takeover performance through proactive adjustments.