Considering Every Available Instance: The Early Development of a Fundamental Problem Solving Skill

Two studies are reported describing the early development in two-and three-year-old children of an ability to consider every one of an array of instances. Children were tested on several tasks unlike either counting or searching tasks. Young children, by about three years of age, attempted to consider each item once and only once. They did so by employing a strategy of sequencing the instances so as to consider each in turn. Employment of this strategy became increasingly skilful over the ages studied, so that with increasing age larger problem sizes and more difficult problems were accomplished successfully. Taken together with recent studies of children's ability to count every item or search all locations for a hidden object, the data reveal early development in preschool children of a fundamental, general problemsolving skill.