Overall, we show the presence of nonlinearities in terms of relative delays (
Figs. 5A2, 5B2, 5C2, 5D2) in the responses to SoS stimuli, as not all relative delays were 0. In the VOR paradigm, the combination did significantly affect the relative delay (
F2,7 = 7.91,
P = 0.005,
η2 = 0.53), post hoc comparisons revealed the relative delay of the 1.0 Hz component in the 1.0/1.9 Hz combination was significantly greater than in both the 0.6/1.0 Hz SoS (
P = 0.013) and the 0.8/1.0 Hz SoS (
P = 0.039); however, only the difference between the 1.0/1.9 Hz and 0.6/1.0 Hz remaining significant after correction for multiple comparisons (
α = 0.017). Furthermore, the relative delay of the 1.0 Hz component in both the 0.8/1.0 Hz and the 1.0/1.9 Hz combinations was significantly greater than 0, indicating a decreased lead of movement over stimulus (0.027 ± 0.020 seconds,
t[7] = 3.75,
P = 0.001 and 0.044 ± 0.022 SD,
t[7] = 5.59,
P = 0.001, respectively). In the OKR paradigm, the frequency combination significantly affected the relative delay (
F1.04,7 = 24.10,
P = 0.001, partial
η2 = 0.78). The delay for the 1.0 Hz probe frequency was greater in the 1.0/1.9 Hz combination than in both the 0.8/1.0 Hz combination (
P = 0.001) and the 0.6/1.0 Hz combination (
P = 0.003), indicated by a positive relative delay. Furthermore, the 1.0 Hz relative delay in the 1.0/1.9 Hz (0.11 ± 0.06 seconds,
t[7] = 4.91,
P = 0.002) frequency combination was significantly greater than a relative delay of 0, indicating an increased delay when presented as the lower frequency of a pair. In the VVOR paradigm, no effect of frequency combination on relative delay was observed (
F2,7 = 1.18,
P = 0.336, partial
η2 = 0.14). In the SVOR paradigm, relative delay was affected by frequency combination (
F2,7 = 101.28,
P < 0.001, partial
η2 = 0.94). The delay for the 1.0 Hz probe frequency was greater in the 1.0/1.9 Hz combination than in the other two combinations (both
P < 0.001). Moreover, only the relative delay in the 1.0/1.9 Hz frequency combination was significantly greater than 0 (0.099 ± 0.026 seconds,
t[7] = 10.72,
P < 0.001).