Quantifying the Interoceptive Fear–Laughter Response: A Restrained-Stimulus Protocol for Induced Tickle-Stress in Human Subjects

Derek, Principal Investigator | Fettish Psychophysiology Laboratory

Abstract

Tickling under immobilized conditions reliably produces a paradoxical affective state in which reported fear (autonomic threat activation) and reactionary laughter (paralinguistic submission vocalization) co-occur. Pilot data (n = 1) demonstrate acute heart-rate elevation (+42 bpm) coincident with laughter burst frequency (11.3 ± 0.7 laughs/30 s), supporting the hypothesis that perceived loss-of-control amplifies tickle hypersensitivity.

Materials & Methods

2.1 Participant

Female, 45 y, 167 cm, 58 kg, normotensive, right-hand dominant, extensive dermal ink (thermoregulatory tattoos; no observed thermal conductivity deviation). Signed IRB-approved consent for BDSM-grade restraint exposure.

2.2 Apparatus

Black MIL-spec nylon webbing (40 mm width) secured to powder-coated steel frame (1.5 in OD tubing) in supine spread-eagle configuration. Strap torque pre-set to 4 N - m (verified with calibrated torque wrench) to eliminate voluntary movement without distal circulation compromise (capillary refill < 2 s). Plantar flexion maintained at 110° via ankle cuffs to elongate plantar aponeurosis, maximizing low-threshold mechanoreceptor access.

2.3 Stimulus Delivery

Single-blind, within-subject design: 3 × 30 s tickle blocks (T1–T3) separated by 60 s recovery. Target sites stimulated in pseudo-random order; wand tip velocity 4 cm/s, medial-to-lateral stroke. Pressure transducer (Honeywell FSG15N1A) mounted proximal to wand tip; output sampled at 1 kHz.

2.4 Physiological Recording

ECG (Lead-II), galvanic skin response (GSR), and diaphragmatic EMG via disposable Ag/AgCl electrodes. Audio captured at 48 kHz for laughter burst spectral analysis (fundamental frequency ~215 Hz).

Results

HR peaked at T2 (142 bpm baseline 100); GSR spike amplitude 3.8 μS. Laughter onset latency 0.9 s post-contact; burst duration 1.4 ± 0.3 s. Subject-reported fear Likert 8/10, pleasure Likert 9/10, confirming ambivalent valence. No safe-word invocation; post-session capillary refill < 2 s, no petechiae.

Discussion

Immobilization-induced helplessness potentiates tickle percept by removing anticipatory motor modulation, consistent with Seligman’s learned-helplessness model. Co-activation of sympathetic arousal (fear) and nucleus ambiguus-mediated laughter indicates competing limbic outputs. Future fMRI studies (tickle-fMRI coil compatible) should parse anterior cingulate vs. periaqueductal gray involvement.

Conclusion

The described protocol safely elicits measurable fear-tickle superimposition, offering a reproducible paradigm for psychosomatic stress and erotic-submission research.

Suspended Hysteria - Catherine Foxx