You Say Potato, I Say — Eleanor Sigel

Abstract

This paper exploits spatial data mapping agricultural suitability for potato cultivation to examine the impact of the crop's post-Columbian introduction on the development of European socio-economic inequality in the succeeding centuries. Building on Nunn and Qian (2011), I extend this previous work along two dimensions: (i) I link potato suitability to civic group membership, patterns of political and cultural values, and, most centrally, a respondent-level communal-individual belief index, relying upon the EVS5/WVS7 Joint Survey; (ii) I shift the focus from levels of income to inequality in income, measuring within-area dispersion of income, proxied by urbanization, and physical welfare, proxied by height. Civic engagement is uncorrelated with potato suitability under this design, suggesting the underlying mechanism is unrelated to prosocial behavior.

Headline results

A one-within-country-SD increase in potato suitability is associated with:

+0.20σ Communal-individual belief index NUTS-1, p = 0.027

−0.16σ Within-region income dispersion (urbanization proxy) NUTS-2, p = 0.003

−0.4σ Within-département conscript-height dispersion (France) N = 36, p = 0.001

~0 Civic engagement (membership share) NUTS-2, p = 0.651, null

Outcome	β (ln wpot)	SE	p	R²	N
Communal-individual belief index	+0.0058**	(0.0025)	0.027	0.868	98
Communal-individual belief index (NUTS-2)	+0.0047*	(0.0024)	0.061	0.744	216
Civic engagement	−0.0017	(0.0037)	0.651	0.795	216
Income dispersion: SD ln(pop 1850)	−0.0498***	(0.0149)	0.003	0.209	179
France height: within-département SD	−0.0816***	(0.0225)	0.001	0.167	36

* p < .10, ** p < .05, *** p < .01. Preferred specification per outcome; full ladders in the paper.

Figures

Hex-binned maps of Europe showing potato suitability and urban-size dispersion — **Figure 1 — Europe: potato suitability and income dispersion.** Hex-binned heatmaps of the Nunn and Qian (2011) Europe-only city panel. Left: mean potato suitability per hex. Right: within-hex SD of ln(city pop 1850), the income-dispersion outcome; darker cells indicate a more uniform local income distribution.

Bubble maps of France showing potato suitability and conscript-height dispersion by département — **Figure 2 — France: potato suitability and conscript-height dispersion.** Each département plotted at its conscript-weighted centroid; bubble area proportional to √(number of conscripts). Left: mean post-1700 potato suitability. Right: within-département SD of conscript height; darker bubbles indicate lower dispersion.

Partial regression binscatter of the communal-individual belief index against potato suitability — **Figure 3 — Communal-individual belief index: partial-regression binscatter.** Left: NUTS-1, country fixed effects and old-world crop suitability partialled out. Right: NUTS-2, full regional geography partialled out. The upward slope confirms the positive, non-outlier-driven relationship reported in the paper.

Partial regression binscatter of civic engagement against potato suitability, showing a null result — **Figure 4 — Civic engagement: partial-regression binscatter.** The fitted line is essentially flat at both NUTS levels, confirming the null result: organizational membership is uncorrelated with potato suitability within country.

Partial regression binscatters of the headline dispersion results for Europe and France — **Figure 5 — Headline dispersion result: partial-regression binscatter.** Left: residualized within-region SD of ln(city pop 1850) vs. residualized potato suitability at NUTS-2. Right: residualized within-département SD of conscript height vs. residualized potato suitability in France (N = 36).

Candidate mechanisms

Nutritional density

The potato is calorie-dense and nutritionally complete per unit of land, raising the local subsistence floor and compressing the spread of consumption and physical well-being.

Appropriability

Tubers are less visible, heavier, and more perishable once harvested than cereals — harder to monitor, store, transport, and tax. Higher potato suitability tends to undermine the development of extractive hierarchies (Mayshar et al., 2022).

Horticulture vs. agriculture scale

Potato cultivation is viable at household scale, while cereals favor larger, more specialized estates. Potato-suitable regions sustain networks of self-sufficient households rather than hierarchies concentrated around large producers — plausibly strengthening kin ties relative to broader social networks.

Data sources

EVS5/WVS7 Joint Survey, v5.0.0 — 156,658 respondents across ~90 countries, fielded 2017–2022 (GESIS Data Archive, ZA7505).
Nunn & Qian (2011) replication archive — country-level potato/old-world crop suitability, the Europe-only city panel (2,206 cities), and French conscript-height microdata (13,646 conscripts, 1658–1770).
Eurostat NUTS-1/NUTS-2 boundaries (2021 vintage) — used for point-in-polygon assignment of cities to modern statistical regions.

Full access instructions and the replication code are in the GitHub repository.