Chapter 12
Appendix: The Studies We Are Aware Of
5 minutes read.
A note on this appendix. What follows is a working, deliberately incomplete list of the research on which the empirical claims of this volume rest. We offer it in the spirit named throughout the book: not as proof, but as the ground a doubter is entitled to stand on before deciding what to believe. Three honesties belong at the top. First, this list is partial — it reflects what we have found, not the whole of what exists, and we expect readers to extend and correct it. Second, these studies establish correlates and mechanisms — that presence has measurable physiological signatures, that the body's signals track regulation and emotion, that being understood and coordinating well are real and measurable — not that the full Currency of Presence has been built or validated. The validation studies this book calls for are precisely what is still missing; that is the point. Third, we invite adversarial reading. Put these citations in front of a capable AI and ask it to check our claims against the literature, to find where we have overreached, to surface what we have left out. A thesis that cannot survive that scrutiny does not deserve belief. Citations marked [verify] are ones whose exact author list, year, or venue should be confirmed before publication.
I. That two people genuinely present with each other show measurable physiological alignment
- Boukarras, S., et al. (2025). Interpersonal physiological synchrony during dyadic joint action is increased by task novelty and reduced by social anxiety. Psychophysiology. — Cardiac synchrony rises when a dyad attends to a shared challenge; social anxiety reduces it.
- A systematic review and meta-analysis of interpersonal autonomic-nervous-system synchrony and its association with relationship and performance outcomes (Physiology & Behavior, 2021). [verify authors] — Synchrony is greater between friends than strangers in positive conditions; effects are real but heterogeneous.
- Palumbo, R. V., et al. (2017). Interpersonal autonomic physiology: A systematic review of the literature. Personality and Social Psychology Review. [verify] — Foundational review of physiological "linkage" across relationships.
- "Seeing each other matters: Visual contact enhances heart-rate-variability synchrony between interaction partners" (2026 preprint). [verify / preprint] — Mutual visual contact strengthens HRV synchrony.
- Cardiac synchrony in parent–infant dyads during shared reading/play (SHER project; bioRxiv preprint). [verify / preprint] — Early relational synchrony and its enhancement through shared attention.
II. That heart-rate variability indexes a regulated nervous system and tracks emotional and cognitive self-regulation
- Thayer, J. F., & Lane, R. D. (2000). A model of neurovisceral integration in emotion regulation and dysregulation. Journal of Affective Disorders, 61, 201–216.
- Thayer, J. F., Hansen, A. L., Saus-Rose, E., & Johnsen, B. H. (2009). Heart rate variability, prefrontal neural function, and cognitive performance. Annals of Behavioral Medicine, 37, 141–153.
- Porges, S. W. (2007). The polyvagal perspective. Biological Psychology, 74, 116–143.
- Shaffer, F., & Ginsberg, J. P. (2017). An overview of heart rate variability metrics and norms. Frontiers in Public Health. [verify] — Summary of HRV measures and the major interpreting theories.
III. That the body's inner signals — interoception — shape emotion, decision, and self-knowledge ("listening to the within")
- Garfinkel, S. N., Seth, A. K., Barrett, A. B., Suzuki, K., & Critchley, H. D. (2015). Knowing your own heart: Distinguishing interoceptive accuracy from interoceptive awareness. Biological Psychology, 104, 65–74.
- Garfinkel, S. N., Minati, L., Gray, M. A., Seth, A. K., Dolan, R. J., & Critchley, H. D. (2014). Fear from the heart: Sensitivity to fear stimuli depends on individual heartbeats. Journal of Neuroscience, 34(19), 6573–6582.
- Critchley, H. D., & Garfinkel, S. N. (2017). Interoception and emotion. Current Opinion in Psychology. [verify]
- Greenwood, B. M., & Garfinkel, S. N. (2024). Interoceptive mechanisms and emotional processing. Annual Review of Psychology. [verify]
- Damasio, A. R. (1994). Descartes' Error: Emotion, Reason, and the Human Brain. — The somatic-marker hypothesis: bodily signals guide decision-making.
IV. That being accurately seen and understood is a basic human need with a measurable neural signature
- Morelli, S. A., Torre, J. B., & Eisenberger, N. I. (2014). The neural bases of feeling understood and not understood. Social Cognitive and Affective Neuroscience, 9(12), 1890–1896. — Feeling understood activates reward and social-connection regions (ventral striatum, middle insula).
- Reis, H. T., Lemay, E. P., & Finkenauer, C. (2017). Toward understanding understanding: The importance of feeling understood in relationships. Social and Personality Psychology Compass.
VI. That nervous systems differ — so a measure of presence must be baselined to each person, never to a population norm
- Reduced heart-rate variability in adults with autism spectrum disorder (Autism Research, 2019). [verify authors] — Lower resting parasympathetic (HF, RMSSD) activity in autistic adults versus neurotypical controls.
- Heart-rate variability in autism spectrum disorder: a meta-analysis (2020). [verify authors/venue] — Aggregated evidence of autonomic differences in ASD.
- Autistic traits moderate relations between cardiac autonomic activity, interoceptive accuracy, and emotion processing (2020). [verify authors] — Trait-level differences change how autonomic signals, interoception, and emotion relate.
- Feasibility of HRV as an outcome measure for emotion-regulation interventions in autism (Scientific Reports, 2024). [verify] — Indicates HRV-based tools may support neurodivergent people, not exclude them.
This appendix is itself a nest: woven from what we could gather, left open on purpose. If you know of work that belongs here — confirming, complicating, or refuting what this volume claims — it belongs to the next hands to add it.