托福TPO30阅读word版下载一
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高中记叙文托福TPO30阅读word版下载一
Role of Play in Development
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Play is easier to define with examples than with concepts. In any ca, in animals it consists of leaping, running, climbing, throwing, wrestling, and other movements, either along, with objects, or with other animals. Depending on the species, play may be primarily for social interaction, exerci, or exploration. One of the problems in providing a clear defin
ition of play is that it involves the same behaviors that take place in other circumstance--dominance, predation, competition, and real fighting. Thus, whether play occurs or not depends on the intention of the animals, and the intentions are not always clear from behaviors alone.
Play appears to be a developmental characteristic of animals with fairly sophisticated nervous systems, mainly birds and mammals. Play has been studied most extensively in primates and canids (dogs). Exactly why animals play is still a matter debated in the rearch literature, and the reasons may not be the same for every species that plays. Determining the functions of play is difficult becau the functions may be long-term, with beneficial effects not showing up until the animal's adulthood.
Play is not without considerable costs to the individual animal. Play is usually very active, involving movement in space and, at times, noimaking. Therefore, it results in the loss of fuel or energy that might better be ud for growth or for building up fat stores in a young animal. Another potential cost of this activity is greater exposure to predators s
ince play is attention-getting behavior. Great activities also increa the risk of injury in slipping or falling.
The benefits of play must outweigh costs, or play would not have evolved, according to Darwin' s theory. Some of the potential benefits relate directly to the healthy development of the brain and nervous system. In one rearch study, two groups of young rats were raid under different conditions. One group developed in an "enriched" environment, which allowed the rats to interact with other rats, play with toys, and receive maze training. The other group lived in an "impoverished" environment in individual cages in a dimly lit room with little stimulation. At the end of the experiments, the results showed that the actual weight of the brains of the impoverished rats was less than that of tho raid in the enriched environment (though they were fed the same diets). Other studies have shown that greater stimulation not only affects the size of the brain but also increa the number of connections between the nerve cells. Thus, active play may provide necessary stimulation to the growth of synaptic connections in the brain, especially the cerebellum, which is responsible for motor functioning and movements.
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