Experiments on the detection of roll motion.

Four experiments investigated the detection of whole-body roll motion by normal adult males. Experiments 1, 3, and 4 employed an earth-horizontal rotation axis, and Experiment 2 an earth-vertical rotation axis. Comparison of Experiments 1 and 2 showed that the presence of gravireceptor stimuli increased the range of detectable angular accelerations and reduced the time required for detection. In Experiment 3, stimuli were presented from a side-down orientation and this increased detection times when compared to roll from the upright. Experiments 1, 2, and 3 used blindfolded subjects; however, Experiment 4 found no effect on detection times of viewing a head-stabilized visual target. The overall data show detection of angular position and velocity and suggest synergistic action of the semicircular canals and gravireceptors. The influence of somatosensory stimuli is considered. Finally, implications of the findings for flight simulators are discussed.