In a previous study, infants' reunion distress at 3 months predicted lower sensorimotor abilities at 4 to 5½ months. This follow-up study extended this prediction to overall cognitive competency at 4 years and examined its relation to early maternal predictors of competency. Controlling for early sensorimotor differences, 3-month distress and anger predicted lower cognitive scores at 4 years, with most of the predicted variance in items tapping short-term memory. Controlling for early emotional and sensorimotor differences, 3-to-5-month maternal responsiveness predicted higher competency at 4 years, with most of the predicted variance in items tapping perceptual performance. Infant joy did not predict later competency. Early negative emotion and maternal responsiveness were independent but equally strong predictors, suggesting different causal mechanisms or different developmental paths.