Does early-life trauma influence battlefield behavior? Evidence from Irish regiments in the American Civil War shows that experiencing the Irish Potato Famine more than a decade earlier made soldiers more likely to desert.
📌 Who was examined and how exposure was identified
- Focus is on Irish troops in the American Civil War who lived through the Potato Famine as children.
- Famine exposure is measured within the Irish group at the individual level using multiple complementary indicators:
- birth cohorts (timing of birth relative to the famine),
- sibling birth order (within-family variation in exposure),
- adult height (a biological marker of early-life deprivation), and
- the geography of surnames in Ireland (linking recruits to local famine severity).
📊 How battlefield behavior was linked to early hardship
- Each measurement strategy consistently indicates that greater famine exposure is associated with higher rates of desertion among Irish soldiers.
- Observable implications from a formal theory of behavior under threat were developed and tested against the data to adjudicate mechanisms.
📈 Key findings and the mechanism
- The most plausible mechanism explaining higher desertion is heightened risk aversion stemming from early-life trauma.
- The famine effect on desertion weakens and effectively disappears once soldiers are socialized into active combat roles through collective risk-sharing (suggesting social integration into combat mitigates the early-life influence).
💡 Why this matters
- Illuminates how nonpartisan, early-life atrocities can leave lasting behavioral legacies that shape contentious behavior in later conflicts.
- Highlights the importance of pre-migration experiences for soldiers drawn from migrant-sending populations.
- Demonstrates the value of combining demographic, biological, and geographic within-group measures to identify long-run behavioral effects of childhood shocks.
