R/T load
bekolblockage
Read a couple of papers on this some years back, apparently there is good evidence that sustained R/T occupancy of more than 70% leads to loss of "picture" due lack of available thinking time.
Results are failure to monitor read-back, clipped transmissions, incapacity of global scan function, and, after prolonged exposure.....increase in stress level and potential for communication failure within operating team [known as "blinkers"], as well as system inability to react to unusual or emergency situations.
Long term exposure believed to be a contributory factor in staff sickness; although some of the trial subjects were found to deny this because it may have seemed to be an admission of lack of ability...[ the human factor ].