What was the core conceptual shift championed by early human factors engineering regarding system failures?

Answer

If a system was difficult to use, the fault often lay with the design, not the user.

A central idea from the era of human factors engineering, which remains central to usability today, was attributing difficulty in use to flawed design rather than user deficiency.

What was the core conceptual shift championed by early human factors engineering regarding system failures?
inventiondesigntestusabilityuser experience