They were monitored for piloerection, bloatedness, tremors, lack of movement, rectal bleeding, and weight loss [all on a scale of 0 — 5, with 5 being very severe; adapted from Madsen et al. (2001)-RSB-. (jpet.aspetjournals.org)
The Goose Bump Detector: a skin piloerection monitoring sensor conformally attached to the dorsal forearm. (sciencedaily.com)
This stimulated piloerection, deforming the sensors and causing their capacitance to notably decrease. (sciencedaily.com)