Nutrition and signaling in slave markets: a new look at a puzzle within the antebellum puzzle

Between 1800 and 1860, mean adult stature of (U.S.) white males declined by nearly an inch, while real output grew substantially, creating the “Antebellum Puzzle.” In contrast, male slaves did not experience a comparable decrease in heights. To explain this puzzle within a puzzle, we show that the benefit of the marginal nutrient exceeded the cost throughout the antebellum era. As a result, it paid for slave owners to engage in the supplemental feeding of slaves, which increased their stature. While this is consistent with a productivity explanation of increased stature, we also argue that informational asymmetries played an important role in the market for slaves. Slave owners had an incentive to signal that their slaves were high-productivity laborers by supplying them with additional food, which positively impacted slave heights. We provide evidence that, distinct from a productivity explanation, signaling mattered in the trend of slave heights.