Hockenbury Discovering Psychology 5th txtbk

390 CHAPTER 9 Lifespan DevelopmentPiaget’s Conservation Task Five-year-oldLaura compares the liquid in the two shortbeakers, then watches as Sandy pours theliquid into a tall, narrow beaker. Whenasked which has more, Laura insists thatthere is more liquid in the tall beaker. AsPiaget’s classic task demonstrates, the average5-year-old doesn’t grasp this principle ofconservation. Even though Laura repeatedthis demonstration several times for thephotographer, she persisted in her beliefthat the tall beaker had more liquid. Wetried the demonstration again when Laurawas almost 7. Now in the concrete operationalstage, Laura immediately understoodthat both beakers held the same amount ofliquid—just as Piaget’s theory predicts.From Concrete Operations to Formal OperationsLogical thinking is evident duringthe concrete operational stage but developsmore fully during the formal operationalstage. At about the age of 12, theyoung person becomes capable of applyinglogical thinking to hypothetical situationsand abstract concepts, such as theprinciples of molecular bonds in this chemistryclass. But as is true of each of Piaget’sstages, new cognitive abilities emergegradually. Having a tangible model tomanipulate helps these students graspabstract chemistry concepts.The classic demonstration of bothirreversibility and centration involves atask devised by Piaget. When Laura was5, we tried this task with her. First, weshowed her two identical glasses, eachcontaining exactly the same amount ofliquid. Laura easily recognized the twoamounts of liquid as being the same.Then, while Laura watched intently, wepoured the liquid from one of the glassesinto a third container that was much tallerand narrower than the others. “Whichcontainer,” we asked, “holds more liquid?”Like any other preoperational child,Laura answered confidently, “The taller one!” Even when we repeated the procedure,reversing the steps over and over again, Laura remained convinced that thetaller container held more liquid than did the shorter container.This classic demonstration illustrates the preoperational child’s inability to understandconservation. The principle of conservation holds that two equal physicalquantities remain equal even if the appearance of one is changed, as long as nothingis added or subtracted (Piaget & Inhelder, 1974). Because of centration, thechild cannot simultaneously consider the height and the width of the liquid in thecontainer. Instead, the child focuses on only one aspect of the situation, the heightof the liquid. And because of irreversibility, the child cannot cognitively reverse theseries of events, mentally returning the poured liquid to its original container. Thus,she fails to understand that the two amounts of liquid are still the same.The Concrete Operational StageWith the beginning of the concrete operational stage, at around age 7, childrenbecome capable of true logical thought. They are much less egocentric in theirthinking, can reverse mental operations, and can focus simultaneously on twoaspects of a problem. In short, they understand the principle of conservation. Whenpresented with two rows of pennies, each row equally spaced, concrete operationalchildren understand that the number of pennies in each row remains the same evenwhen the spacing between the pennies in one row is increased.As the name of this stage implies, thinking and use of logic tend to be limited toconcrete reality—to tangible objects and events. Children in the concrete operationalstage often have difficulty thinking logically about hypothetical situations orabstract ideas. For example, an 8-year-old will explain the concept of friendship invery tangible terms, such as, “Friendship is when someone plays with me.” Ineffect, the concrete operational child’s ability to deal with abstract ideas and hypotheticalsituations is limited to his or her personal experiences and actual events.The Formal Operational StageAt the beginning of adolescence, children enter the formal operationalstage. In terms of problem solving, the formal operational adolescent ismuch more systematic and logical than the concrete operational child.Formal operational thought reflects the ability to think logically evenwhen dealing with abstract concepts or hypothetical situations (Piaget,1972; Piaget & Inhelder, 1958). In contrast to the concrete operationalchild, the formal operational adolescent explains friendship by emphasizingmore global and abstract characteristics, such as mutual trust, empathy,loyalty, consistency, and shared beliefs (Harter, 1990).But, like the development of cognitive abilities during infancy andchildhood, formal operational thought emerges only gradually. Formaloperational thought continues to increase in sophistication throughoutadolescence and adulthood. Although an adolescent may deal effectively