Table 9.
The Causal Effect of Technological Sophistication on Population Density
| (1) | (2) | (3) | (4) | (5) | (6) | |
|---|---|---|---|---|---|---|
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| OLS | OLS | IV | OLS | OLS | IV | |
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| Full Sample | Restricted Sample | Restricted Sample | Full Sample | Restricted Sample | Restricted Sample | |
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| Dependent Variable is Log Population Density in: | ||||||
| 1000 CE | 1 CE | |||||
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| Log Technology Index in Relevant Period | 4.315*** (0.850) | 4.198*** (1.164) | 14.530*** (4.437) | 4.216*** (0.745) | 3.947*** (0.983) | 10.798*** (2.857) |
| Log Land Productivity | 0.449*** (0.056) | 0.498*** (0.139) | 0.572*** (0.148) | 0.379*** (0.082) | 0.350** (0.172) | 0.464** (0.182) |
| Log Absolute Latitude | −0.283** (0.120) | −0.185 (0.151) | −0.209 (0.209) | −0.051 (0.127) | 0.083 (0.170) | −0.052 (0.214) |
| Mean Distance to Nearest Coast or River | −0.638*** (0.188) | −0.363 (0.426) | −1.155* (0.640) | −0.782*** (0.198) | −0.625 (0.434) | −0.616 (0.834) |
| Percentage of Land within 100 km of Coast or River | 0.385 (0.313) | 0.442 (0.422) | 0.153 (0.606) | 0.237 (0.329) | 0.146 (0.424) | −0.172 (0.642) |
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| Continent Dummies | Yes | Yes | Yes | Yes | Yes | Yes |
| Observations | 140 | 92 | 92 | 129 | 83 | 83 |
| R-squared | 0.61 | 0.55 | 0.13 | 0.62 | 0.58 | 0.32 |
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| First-stage F-statistic | – | – | 12.52 | – | – | 12.00 |
| Overid. p-value | – | – | 0.941 | – | – | 0.160 |
Summary – This table presents the causal effect of direct measures of technological sophistication in the years 1000 CE and 1 CE, as determined by exogenous factors governing the timing of the Neolithic Revolution, on population density in the same time periods, while controlling for land productivity, access to navigable waterways, absolute latitude, and unobserved continental fixed effects.
Notes – (i) the technology index for a given time period reflects the average degree of technological sophistication across communications, transportation, industrial, and agricultural sectors in that period; (ii) the almost perfect collinearity between the degree of technological sophistication in the agricultural sector and the timing of the Neolithic transition does not permit the use of the latter as a covariate in these regressions; (iii) log land productivity is the first principal component of the log of the percentage of arable land and the log of an agricultural suitability index; (iv) the IV regressions employ the numbers of prehistoric domesticable species of plants and animals as instruments for the log of the technology index in each of the two periods; (v) in both cases, the statistic for the first-stage F-test of these instruments is significant at the 1 percent level; (vi) the p-values for the overidentifying restrictions tests correspond to Hansen’s J statistic, distributed in both instances as chi-square with one degree of freedom; (vii) a single continent dummy is used to represent the Americas, which is natural given the historical period examined; (viii) regressions (2)–(3) and (5)–(6) do not employ the Oceania dummy due to a single observation for this continent in the IV data-restricted sample; (ix) robust standard error estimates are reported in parentheses; (x) *** denotes statistical significance at the 1 percent level, ** at the 5 percent level, and * at the 10 percent level, all for two-sided hypothesis tests.