Compared behavior of 52 Costa Rican 12- to 23-month-olds with iron-deficiency anemia to that of 139 infants with better iron status. Found that iron-deficient infants maintained closer contact with caregivers; showed less pleasure and playfulness; were more wary, hesitant, and easily tired; made fewer attempts at test items; and attended less to instructions and demonstrations than comparison group infants. (Author)