Concrete-Operational Cognitive Development Late Elementary Grades, 7-11 years

 Distinquishing Characteristics During Concrete Operations * Mental operations are able to be applied to concrete objects and events * Hierarchical classification (e.g., genus, phylum, ... species) * Mastery of several concrete operations, including the 6 listed below. Seriation: Can order a cluster of objects according to a particular feature (e.g., can arrange classmates in a line according to their heights). Numeration: Counting in order from low to high. Decentration: Can coordinate/compensate for two different aspects of a problem 2-D Classification: Can order/group single objects using 2 simultaneous dimensions Reversibility: Can mentally undo a physically performed action. Conservation: See below

 Principle of Conservation Physical objects remain constant in spite of changes in their shape or appearance. (Formally, an object remains the same until something-like mass-is added or taken away). Even when objects appear to change visually (as in the five examples below), the concrete operation of conservation says that the object continues to "conserve" itself.
 Conservation of mass/substance Age 6 Play-doe problem (see reference below). Conservation of length Age 6 Parallel lines problem Conservation of number Age 7 Row of spread-out (in a line) of marbles/coins Conservation of weight Age 7 Play-doe problem Conservation of liquids/volume Age 7-8 Water glass problem Conservation of area Age 9-10 Scattered barns on the horse's farm problem
 For a description of these concrete-operations tasks, see the following journal article available through WebCT: Tomlinson-Keasey et al., (1979). The structure of concrete operational thought. Child Development, 50, 1153-1163.

 Syllogism The concrete operational child can begin to follow, and makes some sense out of, a syllogism, such as the following... If Sue is younger than Sara. And Sara is younger than Sandy. Then Is Sue older than, younger than, or the same age as, Sandy?