The Adolescents

A. The American Academy of Pediatrics recognizes three stages of adolescence. These are early, middle and late adolescence, and each has its own developmental tasks. Teenagers move through these tasks at their own speed depending on their physical development and hormone levels. Although these stages are common to all teenagers, each child will go through them in his or her own highly individual ways.

B. During the early years young people make the first attempts to leave the dependent, secure role of a child and to establish themselves as unique individuals, independent of their parents. Early adolescence is marked by rapid physical growth and maturation. The focus of adolescents’ self-concepts is thus often on their physical self and their evaluation of their physical acceptability. Early adolescence is also a period of intense conformity to peers. ‘Getting along,’ not being different, and being accepted seem somehow pressing to the early adolescent. The worst possibility, from the view of the early adolescent, is to be seen by peers as ‘different’.

C. Middle adolescence is marked by the emergence of new thinking skills. The intellectual world of the young person is suddenly greatly expanded. Their concerns about peers are more directed toward their opposite sexed peers. It is also during this period that the move to establish psychological independence from one’s parents accelerates. Delinquency behavior may emerge since parental views are no longer seen as absolutely correct by adolescents. Despite some delinquent behavior, middle adolescence is a period during which young people are oriented toward what is right and proper. They are developing a sense of behavioral maturity and learning to control their impulsiveness.

D. Late adolescence is marked by the final preparations for adult roles. The developmental demands of late adolescence often extend into the period that we think of as young adulthood. Late adolescents attempt to crystallize their vocational goals and to establish a sense of personal identity. Their needs for peer approval are diminished and they are largely psychologically independent from their parents. The shift to adulthood is nearly complete.

E. Some years ago, Professor Robert Havighurst of the University of Chicago proposed that stages in human development can best be thought of in terms of the developmental tasks that are part of the normal transition. He identified eleven developmental tasks associated with the adolescent transition. One developmental task an adolescent needs to achieve is to adjust to a new physical sense of self. At no other time since birth does an individual undergo such rapid and profound physical changes as during early adolescence. Puberty is marked by sudden rapid growth in height and weight. Also, the young person experiences the emergence and accentuation of those physical traits that make him or her a boy or girl. The effect of this rapid change is that young adolescent often becomes focused on his or her body.

F. Before adolescence, children’s thinking is dominated by a need to have a concrete example for any problem that they solve. Their thinking is constrained to what is real and physical. During adolescence, young people begin to recognize and understand abstractions. The adolescent must adjust to increased cognitive demands at school. Adults see high school in part as a place where adolescents prepare for adult roles and responsibilities and in part as preparatory for further education. School curricula are frequently dominated by the inclusion of more abstract, demanding material, regardless of whether the adolescents have achieved formal thought. Since not all adolescents make the intellectual transition at the same rate, demands for abstract thinking prior to achievement of that ability may be frustrating.

G. During adolescence, as teens develop increasingly complex knowledge systems and a sense of self, they also adopt an integrated set of values and morals. During the early stages of moral development, parents provide their child with a structured set of rules of what is right and wrong, what is acceptable and unacceptable. Eventually, the adolescent must assess the parents’ values as they come into conflict with values expressed by peers and other segments of society. To reconcile differences, the adolescent restructures those beliefs into a personal ideology.

H. The adolescent must develop expanded verbal skills. As adolescents mature intellectually, as they face increased school demands, and as they prepare for adult roles, they must develop new verbal skills to accommodate more complex concepts and tasks. Their limited language of childhood is no longer adequate. Adolescents may appear less competent because of their inability to express themselves meaningfully.

I. The adolescent must establish emotional and psychological independence from his or her parents. Childhood is marked by a strong dependence on one’s parents. Adolescents may yearn to keep that safe, secure, supportive, dependent relationship. Yet, to be an adult implies a sense of independence, of autonomy, of being one’s own person. Adolescents may vacillate between their desire for dependence and their need to be independent. In an attempt to assert their need for independence and individuality, adolescents may respond with what appears to be hostility and lack of cooperation.

J. Adolescents do not progress through these multiple developmental tasks separately. At any given time, adolescents may be dealing with several. Further, the centrality of specific developmental tasks varies with early, middle, and late periods of the transition.

Amateur Naturalists

From the results of an annual Alaskan betting contest to sightings of migra­tory birds, ecologists are using a wealth of unusual data to predict the impact of climate change.

A. Tim Sparks slides a small leather-bound notebook out of an envelope. The book's yellowing pages contain bee-keeping notes made between 1941 and 1969 by the late Walter Coates of Kilworth, Leicestershire. He adds it to his growing pile of local journals, birdwatchers' lists and gardening diaries. "We're uncovering about one major new record each month," he says, "I still get surprised." Around two centuries before Coates, Robert Marsham, a landowner from Norfolk in the east of England, began recording the life cycles of plants and animals on his estate - when the first wood anemones flowered, the dates on which the oaks burst into leaf and the rooks began nesting. Successive Marshams continued compiling these notes for 211 years.

B. Today, such records are being put to uses that their authors could not pos­sibly have expected. These data sets, and others like them, are proving in­valuable to ecologists interested in the timing of biological events, or phen­ology. By combining the records with climate data, researchers can reveal how, for example, changes in temperature affect the arrival of spring, al­lowing ecologists to make improved predictions about the impact of climate change. A small band of researchers is combing through hundreds of years of records taken by thousands of amateur naturalists. And more systematic projects have also started up, producing an overwhelming response. "The amount of interest is almost frightening," says Sparks, a climate researcher at the Centre for Ecology and Hydrology in Monks Wood, Cambridgeshire.

C. Sparks first became aware of the army of "closet phenologists”, as he de­scribes them, when a retiring colleague gave him the Marsham records. He now spends much of his time following leads from one historical data set to another. As news of his quest spreads, people tip him off to other historical records, and more amateur phenologists come out of their closets. The Brit­ish devotion to recording and collecting makes his job easier - one man from Kent sent him 30 years' worth of kitchen calendars, on which he had noted the date that his neighbour's magnolia tree flowered.

D. Other researchers have unearthed data from equally odd sources. Rafe Sa­garin, an ecologist at Stanford University in California, recently studied records of a betting contest in which participants attempt to guess the exact time at which a specially erected wooden tripod will fall through the surface of a thawing river. The competition has taken place annually on the Tenana River in Alaska since 1917, and analysis of the results showed that the thaw now arrives five days earlier than it did when the contest began.

E. Overall, such records have helped to show that, compared with 20 years ago, a raft of natural events now occur earlier across much of the northern hemi­sphere, from the opening of leaves to the return of birds from migration and the emergence of butterflies from hibernation. The data can also hint at how nature will change in the future. Together with models of climate change, amateurs' records could help guide conservation. Terry Root, an ecologist at the University of Michigan in Ann Arbor, has collected birdwatchers' counts of wildfowl taken between 1955 and 1996 on seasonal ponds in the Ameri­can Midwest and combined them with climate data and models of future warming. Her analysis shows that the increased droughts that the models predict could halve the breeding populations at the ponds. "The number of waterfowl in North America will most probably drop significantly with global warming," she says.

F. But not all professionals are happy to use amateur data. "A lot of scientists won't touch them, they say they're too full of problems," says Root. Because different observers can have different ideas of what constitutes, for example, an open snowdrop. "The biggest concern with ad hoc observations is how carefully and systematically they were taken," says Mark Schwartz of the University of Wisconsin, Milwaukee, who studies the interactions between plants and climate. "We need to know pretty precisely what a person's been observing - if they just say 'I noted when the leaves came out', it might not be that useful." Measuring the onset of autumn can be particularly problem­atic because deciding when leaves change colour is a more subjective pro­cess than noting when they appear.

G. Overall, most phenologists are positive about the contribution that ama­teurs can make. "They get at the raw power of science: careful observation of the natural world," says Sagarin. But the professionals also acknowledge the need for careful quality control. Root, for example, tries to gauge the quality of an amateur archive by interviewing its collector. "You always have to worry - things as trivial as vacations can affect measurement. I disregard a lot of records because they're not rigorous enough," she says. Others suggest that the right statistics can iron out some of the problems with amateur data. Together with colleagues at Wageningen University in the Netherlands, environmental scientist Arnold van Vliet is developing statistical techniques to account for the uncertainty in amateur phenological data. With the en­thusiasm of amateur phenologists evident from past records, professional researchers are now trying to create standardised recording schemes for fu­ture efforts. They hope that well-designed studies will generate a volume of observations large enough to drown out the idiosyncrasies of individual recorders. The data are cheap to collect, and can provide breadth in space, time and range of species. "It's very difficult to collect data on a large geo­graphical scale without enlisting an army of observers," says Root.

H. Phenology also helps to drive home messages about climate change. "Be­cause the public understand these records, they accept them," says Sparks.
It can also illustrate potentially unpleasant consequences, he adds, such as the finding that more rat infestations are reported to local councils in warmer years. And getting people involved is great for public relations. "People are thrilled to think that the data they've been collecting as a hobby can be used for something scientific - it empowers them," says Root.