Behavioural Friction Theory: Toward a Common Currency for Behavioural Science
Pødenphant Lund, T. (2026a) · Preprint · v7 live on Zenodo
Behavioural science has more than 20 research traditions (polyvagal theory, cognitive load theory, self-efficacy, psychological safety, nudge theory, attachment, expectancy-value, and others) that do not talk to each other. This paper places them in one map, with Porges, Bandura, Sweller, Kahneman, Edmondson, and the rest in their specific cell of a four-field by five-layer matrix, and shows what falls out when you do.
| DOI | 10.5281/zenodo.19462499 (concept DOI; v7 is the latest version) |
| Target venue | Frontiers in Psychology — Hypothesis & Theory (committed; APC waiver application planned) |
| Status | v7 live on Zenodo (substantial update from v6, May 2026); peer-review submission compression next |
| Length | ~20.5k words (v7) |
| Author | Tomas Pødenphant Lund [ORCID] |
TL;DR
Behavioural science has produced robust findings across dozens of research traditions, but lacks the integrative architecture needed to connect them. Each tradition operates with its own vocabulary, level of analysis, and scope conditions, leaving researchers without a principled basis for relating constructs across domains.
This paper introduces Behavioural Friction Theory (BFT) and proposes friction (the cost the nervous system assigns to a potential action in a given situation) as a common currency for behavioural science. BFT organizes the regulatory system across four computational fields (Safety, Meaning, Ability, Effort) and five functional layers (Biological, Emotional, Inner, Cognitive, External), and describes a single central mechanism (the RACE model) through which regulatory outcomes are determined by the interaction of pressure and bandwidth.
Friction-as-common-currency offers a principled account of three longstanding theoretical problems. First, it provides a unified architecture within which polyvagal theory, self-efficacy research, cognitive load theory, psychological safety research, and nudge theory can be located as descriptions of specific regions of the same regulatory landscape. Second, it reconceptualizes motivation not as a causal mechanism but as a phenomenological description of low net friction, with direct implications for intervention design. Third, it reframes the nature–nurture distinction as a question about intervention: when friction profiles are matched, intervention effectiveness is predicted to be independent of whether those profiles have constitutional or experiential origins.
Twenty-one formal propositions are derived from the theory, each with specification of existing empirical support and minimal test designs. BFT is presented as a theoretical framework inviting empirical scrutiny. It does not replace existing theories; it provides the architecture within which they can be compared, connected, and extended.
Key concepts
- Four functional fields: Safety, Meaning, Ability, Effort — the dimensions through which the nervous system assigns regulatory cost
- Five regulatory layers: Biological, Emotional, Inner, Cognitive, External — nested timescales of friction-modulation
- The RACE model: parallel evaluation of competing routes, accumulation under bandwidth, irreversible commitment
- The Net Friction Rule: a system acts when the expected reduction in overall friction over time exceeds the present cost — and when the friction associated with acting does not exceed substrate capacity
- Pressure, threshold, reactance: the dynamics of route-competition under load
Companion papers
Paper 1 (Lund 2026b) generalises BFT to substrate-universal Friction Theory (FT), with BFT ⊆ FT as the formal nesting relation. The biological fields are recovered as evolutionary derivatives of the safety field under mortality, mobility, and metabolic constraints. See Paper 1 →