Figure 6. The grand average waveform of P1 elicited in the incomplete face condition and complete face condition from Test 1 to 4 . Four electrode sites (PO3/PO4/O1/O2) were averaged.
N170. The main effect of time was significant for N170 latency [F (2.01,34.08) = 32.87, p < 0.001, ηp2 =0.66], with shorter latency for Test 2 than Test 1 (173.68 ± 2.56 ms vs. 188.08 ± 2.29 ms,p < 0.001), Test 3 (192.64 ± 2.44 ms, p< 0.001) and Test 4 (191.40 ± 2.59 ms, p < 0.001) (Figure 7). The main effect of face stimulus was significant for N170 latency [F (1,17)= 57.05, p < 0.001, ηp2=0.77], with longer latency for the incomplete condition (195.57 ± 2.90 ms vs. 177.33 ± 1.81 ms) than for the complete condition (Figure 8). The interaction between time and face stimulus was significant [F (3,51) = 6.63,p = 0.001, ηp2 = 0.28]. In the incomplete condition, N170 latency was shorter in Test 2 than in Test 1 (179.25 ± 3.44 ms vs. 198.06 ± 3.41 ms, p = 0.001), Test 3 (201.89 ± 3.42 ms, p < 0.001), and Test 4 (203.08 ± 3.52 ms, p < 0.001), respectively. In the complete condition, N170 latency was shorter in Test 2 than in Test 1 (168.11 ± 2.13 ms vs. 178.11 ± 2.12 ms, p = 0.001), Test 3 (183.39 ± 2.36 ms, p < 0.001), and Test 4 (179.72.08 ± 2.10 ms, p < 0.001) (Table 3 and Figure 9). No other significant main effects or interactions were found.