Researcher at a glance
- Affiliation: Department of Psychosomatic Medicine, University Hospital Basel, Switzerland
- Orientation: Psychophysiology of respiratory sinus arrhythmia and cardiac vagal control; insistence on respiratory control and target-organ specificity when interpreting RSA; critic of Polyvagal Theory
Key contributions
- Decades of methodological work on RSA as an index of cardiac vagal tone, including the requirement to control respiratory parameters and comparisons of RSA quantification methods.
- With E.W. Taylor, the sustained scientific critique of Polyvagal Theory (Grossman & Taylor 2007; Grossman 2023), arguing its physiological premises are untenable.
- Articulated the ‘category mistake’ framing: RSA is an approximate index of cardiac vagal tone, not a measure of general vagal tone.
Key papers
- Grossman (2023) — Grossman (2023), Biological Psychology 180:108589.
- Grossman & Taylor (2007), ‘Toward understanding respiratory sinus arrhythmia’, Biological Psychology 74:263–285 (not in raw/) — the earlier critique Porges disputes.
Connections
- Debates: Is Polyvagal Theory scientifically valid?
- Related researchers: Stephen W. Porges
Psychosomatic-medicine physiologist and long-time RSA methodologist; the wiki’s voice for the physiological case against Polyvagal Theory. Enters with Grossman (2023).
Position
Grossman’s expertise is the thing PVT is built on — how to measure RSA and what it does and does not mean — which is what makes his critique pointed. His core commitments:
- RSA is an index, not a phenomenon. It approximates cardiac vagal tone under controlled respiration and reports nothing about vagal outflow elsewhere, because of target-organ specificity. Treating it as “vagal tone” is a category mistake.
- The nucleus ambiguus does the cardiac work. Ablation, pharmacogenetic and optogenetic evidence place cardiac vagal control in the NA and essentially none in the dorsal motor nucleus — so PVT’s dorsal-vagal “massive bradycardia,” the source of the “poly,” has no experimental support.
- Nothing here is uniquely mammalian. With comparative physiologist E.W. Taylor, he argues the ventral vagus, myelinated cardiac vagal fibres, RSA-like coupling and complex sociality all predate mammals — dissolving PVT’s evolutionary story.
How to read him in this wiki
The strongest available counterweight to Porges, and a genuine subject-matter expert rather than a hostile outsider — his verdict is that a “broad consensus” of vertebrate-ANS specialists regards each PVT premise as untenable (Is Polyvagal Theory scientifically valid?). Two cautions. First, his 2023 paper is a review that marshals others’ data rather than a decisive experiment, and it explicitly sets aside PVT’s non-cardiac claims as untestable rather than refuting them. Second, the exchange is personal: Grossman edited the Biological Psychology special issue of PVT critiques, and Porges accuses Grossman & Taylor of a strawman and of unattributed paraphrasing (walked back in a corrigendum). The wiki weights his anatomy heavily and reads the polemic on both sides at a discount.