People have wondered for a long time how their personalities，and behaviors are formed.It is not easy to explain why oneperson 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 questions.（61）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.The controversy is often conveniently referred to asnature vs.nurture.
（62）Those who support thenatureside of the conflict believe that our personalities and behavior patterns are largely determined by biological factors.（63）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 to such a great degree that we are almost completely governed by our instincts.
Those who support thenurturetheory，that is，they advocate education，are often called behaviorists.They claim that our environment is more important than our biologically based instincts in determining how we will act.A behaviorist，B.F.Skinner，sees humans as beings whose behavior is almost completely shaped by their surroundings.（64）The behaviorists maintain that，like machines，humans respond to environmental stimuli as the basis of their behavior.
Let us examine the different explanations about one human characteristic，intelligence，offered by the two theories.（65）Supporters of thenaturetheory insist that we are born with a certain capacity for learning that is biologically determined.Needless to say，they don’t believe that factors in the environment have much influence on what is basically a predetermined characteristic.On the other hand，behaviorists argue that our intelligence levels are the product of our experiences.（66）Behaviorists suggest that the child who is raised in an environment where there are many stimuli whichdevelop his or her capacity for appropriate responses will experience greater intellectual development.
The social and political implications of these two theories are profound.（67）In the United States，blacks often score below whites on standardized intelligence tests.This leads somenatureproponents to conclude that blacks are biologically inferior to whites.（68）Behaviorists，in contrast，say that differences in scores are due to the fact that blacks are often deprived of many of the educational and other environmental advantages that whites enjoy.
Most people think neither of these theories can yet fully explain human behavior.
The fact is that the energy crisis，which has suddenly been officially announced，has been with us for a long time now，and will be with us for an even longer time.Whether Arab oil flows freely or not，it is clear to everyone that world industry cannot be allowed to depend on so fragile a base.（71）The supply of oil can be shut off unexpectedly at any time，and in any case，the oil wells will all run dry in thirty years or so at the present rate of use.
（72）New sources of energy must be found，and this will take time，but it is not likely to result in any situation that will ever restore that sense of cheap and plentiful energy we have had in the times past.For an indefinite period from here on，mankind is going to advance cautiously，and consider itself lucky that it can advance at all.
To make the situation worse，there is as yet no sign that any slowing of the world’s population is in sight.Although the birthrate has dropped in some nations，including the United States，the population of the world seems sure to pass six billion and perhaps even seven billion as the twentyfirst century opens.
（73）The food supply will not increase nearly enough to match this，which means that we are heading into a crisis in the matter of producing and marketing food.
Taking all this into account，what might we reasonably estimate supermarkets to be like in the year2001?
To begin with，the world food supply is going to become steadily tighter over the next thirty years—even here in the United States.By2001，the population of the United States will be at least two hundred fifty million and possibly two hundred seventy million，and the nation will find it difficult to expand food production to fill the additional mouths.（74）This will be particularly true since energy pinch will make it difficult to continue agriculture in the highenergy American fashion that makes it possible to combine few farmers with high yields.
It seems almost certain that by2001the United States will no longer be a great foodexporting nation and that，if necessity forces exports，it will be at the price of belttightening at home.
In fact，as food items will end to decline in quality and decrease in variety，there is very likely to be incresing use of flavouring additives.（75）Until such time as mankind has the sense to lower its population to the point where the planet can provide a comfortable support for all，people will have to accept moreunnatural food.
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