Fig. 6.

Bias and threshold of visual and inertial heading discrimination across subjects by gaze position. Error bars represent ±1 SE. Conditions at the same visual motion coherence were offset slightly to keep error bars from overlapping. A–C: the PSE based on eye position. ●, Purely inertial stimuli; □, purely visual stimuli; ■, the visual-inertial combined conditions. A negative bias indicates that the PSE shifted left, while a positive bias indicates a right shift. Dashed line, performance predicted from optimal weights (Eq. 2) calculated from mean thresholds. D–F: average thresholds by eye position. Dashed line, thresholds predicted from optimal stimulus combination.