The Long-Term Effects of Africa's Slave Trades - Social Sciences ...

and these countries continue to be the most underdeveloped today. In other
words, the slave trades may be correlated with unobserved country characteristics,
resulting in biased estimates of the effect of the slave trades on
economic development.
I pursue a number of strategies to better understand the reason behind
the relationship between slave exports and current economic performance.
First, I review the evidence from African historians on the nature of selection
into the slave trades. I also use historic data on pre-slave trade population
densities to examine whether it was the less developed parts of Africa that
selected into the slave trades. Both sources of evidence show that it was actually
the most developed areas of Africa that tended to select into the slave
trades. I discuss the reason behind this seemingly paradoxical relationship
in detail. Second, I use two sets of instruments to estimate the causal effect
of the slave trades on subsequent economic development. The first instruments
are the sailing distances from each country to the nearest location of
demand for slave labor in each of the four slave trades. The second is initial
population density, controlling for current population density in the second
stage. Like the OLS coefficients, the IV coefficients are negative and significant,
suggesting that increased extraction during the slave trades caused
worse subsequent economic performance. The final strategy that I pursue
is to control for a number of additional observable country characteristics.
These results also indicate that the slave trades did have a negative effect
on subsequent economic development.
I then explore the precise channel of causality underlying the relationship
between slave exports and subsequent economic development. Using
historical evidence as a guide, I examine whether the procurement of slaves
through internal warfare, raiding, and kidnapping resulted in subsequent
state collapse, ethnic fractionalization, and a deterioration in the quality
of judicial institutions. I find support for the view that the slave trades
resulted in weak, politically fragmented states, ethnic fractionalization, and
poor judicial institutions.
These findings complement the research of Engerman and Sokoloff (1997,
2002) and Sokoloff and Engerman (2000), which shows that slavery in the
New World resulted in the evolution of institutions that were not conducive
for economic growth. 2 My results show that not only was the use
of slaves detrimental for a society, but the production of slaves, which occurred
through domestic warfare, raiding, and kidnapping, also had negative
2 Also see Lagerlöf (2005) who shows that within the U.S., the states that relied the
most heavily on slavery in the past have the lowest income levels today.
3