Signal detection theory (SDT) is a multi-component ratio method for assessing perceptual performance. It can be applied in backward masking, such as the presentation of a brief target image followed by a noise image that can render a target imperceptible. Previously, we implemented a methodology for backward masking that included individualized thresholds to achieve unconscious presentations and involved dedicated SDT-component analyses. We showed that a specific SDT-component, namely, false positives, such as erroneously reporting that an arousing facial stimulus was presented, involved increases in physiological and emotional responses. In this manuscript, we explored this effect outside our individual-thresholds paradigm. For the first time in relevant research, we recruited participants using trial-contour power calculations for false positive responses. We presented emotional faces for 16.67 ms masked with noise images for 116.67 ms. We showed that false-positive responses for emotional faces were characterised by pre-trial arousal, and post-trial arousal increases, and high emotional and confidence ratings. These outcomes were most pronounced for the misperception of fearful faces. Based on these findings, we discussed the possibility of a mechanism for partial self-encapsulated emotional-experiential apperception. We emphasised the possibility of a fear primacy socio-emotional response module during combined visual ambiguity and high psychophysiological arousal.