SES affects infant cognitive flexibility.

Cognitive flexibility requires processing multiple sources of information and flexible adaptation of behavioral responses. Poverty negatively impacts cognitive control in young children, but its effects on infants are not well-understood. This study investigated longitudinally the development of cognitive flexibility in low-income infants. Thirty-two infants (15 low-SES, 17 high-SES) were tested at 6, 9, and 12 months of age. Cognitive flexibility was measured with a perseverative reaching task, where infants were taught to reach to one location and then asked to switch to a second location. High-SES infants replicated the typical developmental trajectory, reaching randomly at 6 months, perseverating at 9 months, and reaching correctly at 12 months. In contrast, the low-SES infants showed a delayed pattern, reaching correctly at 6 months, randomly at 9 months, and perseverating at 12 months. Links between cognitive flexibility and frontal cortex development are explored as a potential mechanism.