People have wondered for a long time how their personalities and behaviors are formed. It’s not easy to explain why one person is intelligent and another is not, or why one is cooperative and another is competitive.
Social scientists are, of course, extremely interested in these types of question. They want to explain why we possess certain characteristics and exhibit certain behaviors. There are no clear answers yet, but two distinct schools of thought on the matter have developed. As one might expect, the two approaches are very different from each other, and there is a great deal of debate between proponents of each theory. The argument is often conveniently referred to as nature vs. nurture.
Those who support the “nature” side of the conflict believe that our personalities and behavior patterns are largely determined by biological and genetic factors. That our environment has little, if anything, to do with our abilities, characteristics and behavior is central to this theory. Taken to an extreme, this theory maintains that our behavior is predetermined(注定)to such a great degree that we are almost completely governed by our instincts(本能).
Proponents of the “nurture” theory, or, as they are often called, behaviorists, claim that our environment is more important than our biologically based instincts in determining how we will act. Behaviorists see humans as beings whose behavior is almost completely shaped by their surroundings. Their view of the human being is quite mechanistic; they maintain that, like machines, humans respond to environmental stimuli (something that helps sb./ sth. to develop better and more quickly)as the basis of their behavior.
The social and political connections of these two theories are significant. In the United States, for example, blacks often score below whites on standardized intelligent test. This leads some “nature” proponents to conclude that blacks are genetically worse than whites. Behaviorists, in contrast, say that the differences in scores are due to the fact that blacks are often robbed of many of the educational and other environmental advantages  that whites enjoy, and that, as a result ,they do not develop the same responses that whites do.
Neither of these theories can yet fully explain human behavior. In fact, it is quite likely that the key to our behavior lies somewhere between these two extremes. That the argument will continue for a long time is certain.
The author is mainly concerned about solving the problem  .

A．why our personalities and behaviors differ

B．what makes different stages of intelligence

C．how social scientists form different theories

D．what causes the “nature/ nurture” argument

The underlined word “proponents” can best be replaced by  .

A．approaches	B．advocates
C．principles	D．characters

Which of the following statements may be supported by the “nature” school?

A．We are born with certain personalities and behaviors.

B．Environment has nothing to do with our personalities.

C．Abilities and characteristics are showed by behaviors.

D．Only extreme behaviors are determined by instincts.

What can we learn about the behaviorists?

A．They believe human beings are mechanical.

B．They compare our behaviors to the machines.

C．They suggest that we react to the environment as the machines do.

D．They agree that the mechanistic theory can be applied on us as well.