The concrete operational stage takes place from about age seven to about age eleven. It is concurrent with Freud’s latency age and Erikson’s industry vs. inferiority stage. By this stage, children have mastered the basic rules of the physical world. They understand the laws of space and time. This stage is marked by the conservation of volume, substance, number, and other physical features. Likewise, this stage is marked by the capacity for decentration. In other words, the child no longer gets hooked on only one feature of a situation. The child can coordinate several features of an object, such as height and width, into a more comprehensive understanding of how objects change and how they stay the same.