The Physics of Learning: How Race-Architecture Constraints Explain What We Know About Teaching, Communication, and Understanding

Three of learning science's most robust traditions, cognitive load theory, desirable difficulties, and psychological safety, are each empirically excellent and mechanically thin. This paper argues they are local consequences of one shared constraint, bounded-capacity race-architecture, and translates that mechanics to human learning, teaching, and communication for audiences in education research, instructional design, and organisational psychology. Abstract. Three traditions of learning science — cognitive load theory and multimedia learning (Sweller, Mayer); desirable difficulties and retrieval practice (Bjork, Roediger, Karpicke); psychological safety and need-prepotency (Maslow, Edmondson) — are each empirically excellent and mechanically thin. They terminate at cognitive-architecture-as-given, representational-properties-as-given, and behavioural-information-flow-as-given. This paper proposes that the three are local consequences of the same shared physical constraints: bounded-capacity race-architecture, friction as the cost of unresolved competing routes, hysteresis as encoding-through-loading, and the Net Friction Rule as integrated-friction optimisation. The substrate-level account is empirically anchored by language-model substrates where the mechanism is mechanically visible, and the same constraints derive, rather than postulate, working-memory limits, the testing effect, the spacing effect, expertise reversal, and prepotency of safety-field activity over substantive-content processing. Implications for curriculum design, moment-by-moment classroom diagnosis, technical and organisational communication, and change management are developed. Four falsification conditions are specified. v6 (August 2026) — attribution revision. A paper on the physics of learning states that substrates encode processing friction rather than presented information, and the refusal to treat the input as the determinant is Craik and Lockhart's (1972). They are now cited at that claim, at the site where it is load-bearing rather than in the passage where phenomena are integrated, and their thesis is given in their terms: retention varies with the depth of the operation performed on material rather than with the material presented. The difference is stated exactly and in one direction only. Theirs is a claim about the quality of retention as a function of processing depth; the substrate claim here is about the object encoded, so material that opens no race leaves nothing to persist however deeply it is analysed. Depth and race-opening are separate variables, and it is the second that is made load-bearing. Earlier versions remain in the version history.