## 4 Discussion and Conclusions
Multivariate analysis of the data in occipito-temporal clusters sampled at 250 Hz still failed to find a statistically significant effect in the N170 component as observed in ERP mean amplitude analysis. Occipito-temporal electrodes were chosen based on the existing findings [19; 20; 62] to optimize the chance of finding any effects of experimental manipulation on early visual components. This is one advantage of ERP mean amplitude approach over multivariate analysis. Another reason for superior performance of ERP mean amplitude analysis is its sensitivity to short-lasting effects. A previous study [34] has pointed out the possibility that cluster-based permutation is less sensitive than alternative procedures such as FDR correction [63] in detecting small clusters of activation, which is disadvantageous particularly for the detection of ephemeral effects in the early latency range. It is of great value for the advancement of data-driven analysis of ERP data to refine a novel procedure to balance sensitivity to and controlling false-positives of meaningful but short-lasting temporal clusters. Neither the conventional ERP analysis nor the GFP analysis revealed notable effects during the late latency range (500-700 ms after stimulus onset). At the same time, the results of diagonal decoding in multivariate analysis have shown that the pattern of scalp ERP elicited by self-face can be discriminated from that elicited by familiar faces after 500 ms for original and degraded versions. These results show the benefit of multivariate analysis in investigating electrophysiological bases of face processing. The averaged RT for making manual responses was about 500 ms in the present task. Thus, the long-latency effect revealed by multivariate analysis is not directly linked to perceptual discrimination of facial identity, but presumably to later cognitive and evaluative stages of self-face processing. Temporal generalization analysis revealed that this effect was temporally stable for the original, but not for the degraded version of faces, which indicates that neural activation underlying the long-latency effect differs between the original and degraded versions. As for actual self-faces, several previous studies have shown that an attentional effect of self-related information emerges around 500 ms after stimulus onset [13; 19]. Thus, one explanation for the long-latency effect for original faces is the vigorous neural activations originating from the potency of self-face to capture one's visuo-spatial attention [40; 41; 64]. To the best of our knowledge, the present study is the first to measure ERP responses to aesthetically degraded versions of self-face. Thus, one can only make speculations about the functional significance of an identity-related effect observed for aesthetically degraded versions of faces at the long-latency range. Several behavioural studies found that self-threatening information triggers a psychological defence mechanism that protects positive self-image. [PERSON] et al. (2006) [6] investigated how activation of negative self-conception influences evaluation of own and other's attractiveness. Their main finding was that the participants primed with negative conception avoided negative self-evaluation and gave lower attractiveness ratings to attractive others to maintain their self-esteem. Based on these findings, I tentatively propose that differential ERP pattern between self and other familiar faces in aesthetically degraded condition reflects the activation of a defensive reaction triggered by viewing aesthetically degraded self-images that are demeaning to the participants. There are several limitations to the present study. First, only young adult females with relatively small sample size were recruited as participants, which severely limits the generalizability of the present findings. A recent study [65] reported that a larger proportion of females versus males makes an effort to edit their selfies shared on social-networking services.