Fig 3. Average physiological changes in participants who had piloerection (black bars) and their matched partners (white bars).

Black bars depict the difference in physiological activity between the entire piloerection passage and a random control passage of similar length within the same stimulus and subject. White bars depict the same difference scores, but for matched partner subjects who did not have piloerection in either of the passages. All scores are normalized with respect to activity during the baseline period. Ek = emotional index E_κ, HR = heart rate, RF = respiratory frequency. HR and E_κ scores are different from zero in the piloerection condition (black bar), RF scores are different from zero in the no-piloerection condition (white bar). The differences in HR scores and in E_κ scores (black versus white bars) are significant on a 0.05 significance level.