We fi nd that southern blacks responded collectively to political and economic opportunities after Emancipation, but only in places where specific conditions were
满意。黑人会(一个工作d lived) in close proximity to each other in counties where labor intensive plantation crops were grown. Spatial proximity would have resulted in more connected social networks. These connected networks would have supported the formation of larger coalitions of black activists during Reconstruction and larger coalitions of black workers moving together to northern cities during the Great Migration. Our theory places additional structure on this relationship. Coalitions will not form and there will be no association between network connectedness and
the outcomes of interest { political participation and migration { up to a threshold, followed by a positive association above the threshold. Voting and migration patterns across counties are consistent with the theory - there is no association with our crop-based measure of network connectedness up to a threshold point at which a steep, monotonic relationship begins. This finding is robust to rigorous testing, and these tests show that the specific nonlinearity implied by the theory is not obtained for blacks at other points in time, for whites, or for other determinants of voting and migration. Blacks from southern counties where labor intensive crops were
grown accounted for a disproportionate share of northern migrants, and these migrants appear to have benefi ted from network externalities, as they moved to the same destination cities. |
