We initially tested whether only extreme levels of physical discipline were associated with increases in externalizing behavior. If this were the case, we would expect a non-linear trend in externalizing as a function of harm exposure, such that externalizing does not increase appreciably at low to medium levels of environmental risk but accelerates beyond some threshold of risk. To address this possibility, we assessed the fit of linear and quadratic models and found no significant improvement in fit with the addition of a quadratic term (R2Δ = .000; FΔ1,247 = 0.008, p = 0.930). This finding suggests that externalizing behavior increases in a linear manner even at high levels of environmental risk exposure.
