Part IV · Tinbergen
Niko Tinbergen asked four questions of any behaviour. Sorting the forty-seven categories onto those questions shows where the evidence actually is.
How does arousal attach to feet in a living brain? Candidates: A1-A3 (maps), A6, A8, B1-B5 (learning circuitry), A5 (dopamine). Real evidence: learning can attach arousal to cues (B1, B3, B4, C4). Maps exist and are adjacent (A3). Missing: any neural signature of podophilia.
What in a life history builds it? B6-B8, B2, D3-D4 as ambient culture, E3 as later amplifier. Real evidence: Weinberg’s reconstructed pubertal, often positive, peer-linked onsets (E5/E2 hybrid). Field pairing in adults (B4). Missing: prospective childhood data.
What is inherited or byproduct? C1, C4, C5, A7. Real evidence: comparative sexual learning is strong (C4, E1). Human heritability of this trait: absent. Male bias: mixed by instrument (C5).
What, if anything, does it do? C2-C3 offer adaptationist bait. This dossier’s stance: no established function. Byproduct is the default. Historical institutions (D1) gave the cue social functions (status, gender, beauty) that are not the same as an evolved function of the fetish.
A learning-byproduct core (C1 + B1 + C4) is compatible with everything that does not claim a dedicated foot module. Cultural concealment and footwear fashion (D3, D4) can raise the odds that the learned CS is a foot. Individual conditionability (B5) and possible weak familial liability (A7, gap) can explain who learns. Digital markets (E3, E4) can explain persistence and elaboration. Ego-syntonic/dystonic clustering (G4) can explain who suffers. Religious foot rites (F1-F5) can sit in the same cultures without being the engine (F6, Shekarchi).
Adjacency (A1) is compatible with learning if it only supplies a prior that makes foot CSs a bit more relevant (a Hoffmann-style relevance effect). It is not compatible with Turnbull’s reading if one insists that S1 is the erotic map and that feet should therefore be widely erogenous to touch.
The single hypothesis that would explain foot specificity most cleanly, if true, remains somatosensory adjacency with erotic cross-activation (A1), possibly moved out of S1 into an affective body map (Turnbull’s own suggestion). It would predict a foot > hand differential even in cultures that do not hide feet, a tactile erogenous boost, and an imaging signature.
What would settle it: a pre-registered fMRI or 7T study of people with primary podophilia versus controls, stimulating foot, hand, and genitals, testing overlap and functional connectivity, plus a parallel erogenous-rating replication of Turnbull restricted to that clinical/community group. If overlap is no greater than in controls, A1 as specificity engine is in serious trouble. If it is greater, A1 is promoted, still not to E1 until replicated.
The runner-up specificity engine is cultural: concealment plus institutionalized attention (D1, D3) plus the sheer frequency of feet as available CS in dressing and undressing. That predicts historical and cultural patchiness. It would be settled by a cross-national item that tracks clothing rules against foot-interest rates.
No category is the answer. The field is a graded map. Unknown remains a legal word for the developmental pathway and for the foot differential.
A Neurobiology. Maps and adjacency are real. Erotic spillover is not shown. Lesion and drug cases show that sexuality is biologically labile and do not specify feet. Genetics of podophilia: gap.
B Learning. The strongest etiological domain. Conditioning is possible in both sexes and in the field. The lab-to-life gap and the silence on foot specificity remain.
C Evolution. Comparative learning is solid (E1). Human adaptationist stories about feet are unproven. Function: unknown. Default: byproduct.
D History. Footbinding and the European sexological archive are real. They are interpretive as causes. Global distribution: unknown.
E Sociology. Relative prevalence (feet first among fetish groups) is the best rank-order in print. Population ‘fetishism’ items are common and mode-sensitive. They rarely name feet. Digital creation versus concentration: untested.
F Religion. Practices and emic meanings are well documented. Causal links to erotic interest are Layer 3 and, in the one empirical test, unsupported for belief type.
G Clinical. Distress/impairment is the disorder line. Ego-dystonic clustering tracks depression in one unreplicated study. Forensic lists are not etiologies.
H Philosophy. Intellectual history and ethics. Not mechanisms.
