15.1 Logic and Self

Brain maturation, additional years of schooling, moral challenges, increased independence, and intense conversations all occur between the ages of 11 and 18. These aspects of the adolescent’s development propel impressive cognitive growth, as teenagers move from egocentrism to abstract logic.

Egocentrism

During puberty, young people center on themselves, in part because maturation of the brain heightens self-consciousness (Sebastian et al., 2008). Young adolescents grapple with conflicting feelings about their parents and friends, thinking deeply (but not always realistically) about their future. Adolescents ruminate (via phone, text, and private talk) about each nuance of everything they have done, are doing, and might do.

Adolescent egocentrism—thinking intensely about themselves and about what others think of them—was first described by David Elkind (1967). Egocentrism is evident throughout adolescence, especially in teenagers who have problems such as delinquency, aggression, or eating disorders, or when entering a new educational institution (middle school, high school, or college) (Schwartz et al., 2008).

In egocentrism, adolescents regard themselves as much more unique, special, and admired or disliked than they actually are. For example, few adolescent girls are attracted to boys with pimples and braces, but Edgar was so eager to be recognized as growing up that he did not realize this, according to his older sister:

Egocentrism leads adolescents to interpret everyone else’s behavior as if it were a judgment on them. A stranger’s frown or a teacher’s critique can make a teenager conclude that “No one likes me” and then deduce that “I am unlovable” or even “I can’t leave the house.” More positive casual reactions—a smile from a sales clerk or an extra-big hug from a younger brother—could lead to “I am great” or “Everyone loves me,” with similarly distorted self-perception.

Acute self-consciousness about physical appearance is probably more prevalent between the ages of 10 and 14 than at any other time in one’s life (Rankin et al., 2004). Most young adolescents would rather not stand out from their peers, hoping instead to blend in, although they may want to flaunt adult standards. Conformity rules.

The personal fable is the belief that one is unique, destined to have a heroic, fabled, even legendary life. Some 12-year-olds plan to star in the NBA, or to become billionaires, or to cure cancer. Others believe they are destined to die an early, tragic death; for them smoking, eating junk food, or other habits that could lead to midlife cancer or heart disease are no problem. This fable may coexist with the invincibility fable, the idea that death will not occur unless destiny allows it, and therefore fast driving, unprotected sex, or addictive drugs will do no harm.

In every nation, most volunteers for military service—hoping that they will be sent into combat—are under the age of 20. Young recruits take risks more often than older, more experienced soldiers (Killgore et al., 2006). Another example of the invincibility fable comes from online chat rooms: despite adult warnings, teenagers reveal personal information to electronic “friends” (McCarty et al., 2011).

Egocentrism creates an imaginary audience in the minds of many adolescents. They believe they are at center stage, with all eyes on them, and they imagine how others might react to their appearance and behavior.

One woman remembers:

This woman went on to become an expert on the adolescent brain; she knew from personal experience that “adolescents are hyperaware of other’s evaluations and feel they are under constant scrutiny by an imaginary audience” (Somerville, 2013, p. 124).

Egocentrism is sometimes blamed for every foolish action an adolescent takes (Leather, 2009). However, that is too simple a generalization. First, some adolescents do not feel they are invincible at all; instead they have exaggerated perceptions of risks (Mills et al., 2008). Neurological studies show that in some ways adolescents are fearless. Yet, particularly regarding social disapproval, adolescents are more anxious than people of any other age (Pattwell et al., 2013).

Second, egocentrism may be protective when “an individual enters into a new environmental context or dramatically new life situation” (Schwartz et al., 2008, p. 447) because being sensitive to social cues speeds adjustment. The egocentrism of adolescents brings psychic benefits as well as dangers (Martin & Sokol, 2011).

Formal Operational Thought

Piaget described a shift to formal operational thought, as adolescents move past concrete operational thinking and consider abstractions, including “assumptions that have no necessary relation to reality” (Piaget, 1972, p. 148).

One way to distinguish formal from concrete thinking is to compare curricula in primary school and high school. Here are three examples:

1. Math. Younger children multiply real numbers, such as 4 × 3 × 8; adolescents can multiply unreal numbers, such as (2x)(3y) or even (25xy²)(−3zy³).
2. Social studies. Younger children study other cultures by considering daily life—drinking goat’s milk or building an igloo, for instance. Adolescents can consider the effect of “gross national product” and “fertility rate” on global politics.
3. Science. Younger students water plants; adolescents test H₂O in the lab.

Each of these examples shows that teachers realize what their students can understand.

Piaget and his colleagues devised a number of tasks to assess formal operational thought (Inhelder & Piaget, 1958); “in contrast to concrete operational children, formal operational adolescents imagine all possible determinants … [and] systematically vary the factors one by one, observe the results correctly, keep track of the results, and draw the appropriate conclusions” (P. H. Miller, 2011, p. 57).

One of their experiments (diagrammed in Figure 15.1) required balancing a scale by hooking weights onto the scale’s arms. To master this task, a person must realize the reciprocal interaction between distance and the weights’ heaviness. Therefore, a heavy weight close to the center can be counterbalanced with a light weight far from the center on the other side.

Balancing was not understood by the 3- to 5-year-olds. By age 7, children balanced the scale by putting the same amount of weight on each arm, but they didn’t realize that the distance from the center mattered. By age 10, children experimented with location and weight, using trial and error, not logic. Finally, by about age 13 or 14, some children hypothesized about the reciprocal relationship, developing the correct formula (Piaget & Inhelder, 1969).

One hallmark of formal operational thought is the capacity to think of possibility, not just reality. “Here and now” is only one of many possibilities, including “there and then,” “long, long ago,” “not yet,” and “never.” As Piaget said:

Adolescents are therefore primed to engage in hypothetical thought, reasoning about if–then propositions that do not reflect reality. For example, consider this question (adapted from De Neys & Van Gelder, 2009):

Children answer “No!” They know that whales swim, not walk; the logic escapes them. Some adolescents answer “Yes.” They understand the concept of if, and therefore the counterfactual phase “if all mammals.”

Hypothetical thought transforms perceptions, but not necessarily for the better. Adolescents might criticize everything from their mother’s spaghetti (it’s not al dente) to the Gregorian calendar (it’s not the Chinese or Jewish one). They criticize what is because of their hypothetical thinking about what might be and their growing awareness that other families and cultures differ from their own. That complicates decision making when it comes to immediate, practical questions (Moshman, 2011).

In developing the capacity to think hypothetically, by age 14 or so adolescents become capable of deductive reasoning, or top-down reasoning, which begins with an abstract idea or premise and then uses logic to draw specific conclusions. In the example above, “if all mammals can walk” is a premise. By contrast, inductive reasoning, or bottom-up reasoning, predominates during the school years, as children accumulate facts and experiences (the knowledge base) to aid their thinking. Since they know whales cannot walk, that trumps the logic.

In essence, a child’s reasoning goes like this: “This creature waddles and quacks. Ducks waddle and quack. Therefore, this must be a duck.” This reasoning is inductive: It progresses from particulars (“waddles” and “quacks”) to a general conclusion (“a duck”). By contrast, deduction progresses from the general to the specific: “If it’s a duck, it will waddle and quack” (see Figure 15.2).

An example of the progress toward deductive reasoning comes from how children, adolescents, and adults change in their understanding of the causes of racism. Even before adolescence, almost everyone is aware that racism exists—and almost everyone opposes it. However, children tend to think the core problem is that some people are prejudiced. Using inductive reasoning, they think that the remedy is to argue against racism when they hear other people express it. By contrast, older adolescents think, deductively, that racism is a society-wide problem that requires policy solutions.

This example arises from a study of adolescent agreement or disagreement with policies to remedy racial discrimination (Hughes & Bigler, 2011). Not surprisingly, most students of all ages in an interracial U.S. high school recognized disparities between African and European Americans and believed that racism was a major cause.

However, the age of the students made a difference. Among those who recognized marked inequalities, older adolescents (ages 16 to 17) more often supported systemic solutions (e.g., affirmative action and desegregation) than did younger adolescents (ages 14 to 15). Hughes and Bigler wrote: “during adolescence, cognitive development facilitates the understanding that discrimination exists at the social-systemic level … [and] racial awareness begins to inform views of race-conscious policies during middle adolescence” (2011, p. 489).

Many cognitive scientists study how people of all ages sometimes think illogically. Such failures are apparent throughout adolescence (Albert & Steinberg, 2011), but there is one age-related difference: younger adolescents are more confident of their illogical ideas than older adolescents are (De Neys, 2013).

One example is the sunk cost fallacy: the belief of people who have spent if money, time, or effort that cannot be recovered (a cost already “sunk”) that they must continue to pursue their goal because otherwise all previous effort in reaching that goal will be wasted (Cunha & Caldieraro, 2009). It is this fallacy that leads people to pour money into repairing a “lemon” of a car, remain in a class they are failing, stay in an abusive relationship, and so on.

Another common fallacy is base rate neglect (Kahneman, 2011), in which people ignore information about the frequency of a phenomenon. For example (cited by Kahneman, 2011, p. 151), if a stranger on the subway is reading the New York Times, which is more likely?

The answer is no college degree. Far more subway riders have no degree than have a Ph.D. (perhaps 50:1). But people tend to ignore that base rate, and instead conclude that a Ph.D. recipient is more likely to read the New York Times than someone without a degree. That is base rate neglect.

Egocentrism makes base rate neglect more likely and more personal. For instance, a teen might not wear a bicycle helmet, feeling invincible despite statistics, until a friend is brain-damaged in a biking accident. “When adolescents take unjustified risks, it is often because of the weakness of their analytic systems, which provide an inadequate check on impulsive or ill-considered decisions” (Sunstein, 2008, p. 145).

Not only adolescents but also adults sometimes reason like concrete operational or even preoperational children. Logical fallacies occur at every age, and “No contemporary scholarly reviewer of research evidence endorses the emergence of a discrete new cognitive structure at adolescence that closely resembles … formal operations” (Kuhn & Franklin, 2006, p. 954). Nonetheless, something shifts in cognition after puberty: Piaget was correct when he concluded that most older adolescents can think differently than most children do.