Nature Vs. Nurture

Nature vs. Nurture

The dubious history of the heredity environment controversy can be

easily traced as far back as the start of the present century with at least some

historical evidence placing the roots of this dispute in the time of John Locke.

This controversy has continued despite continual reiteration that the critical

question is not how much of a trait is due to heredity and how much is due to

environment, but rather how environment transact to influence development." (

Wachs , 1983, p. 386).

This paper will focus on the nature/nurture controversy and the extent

to which an individuals intellectual level is determined either by inborn

intelligence or by environmental factors.

The relative powers of nature and nurture have been actively pursed by

psychologists and biologists striving to determine how heredity and environment

influence the development of intelligence.

Before we can go on to discuss the relationships between intelligence

and the controversy that exists between the different schools of thought

regarding inherited or environmental issues we must have an understanding of

what intelligence really is.

Of all the words used in pressed day psychology, intelligence is one of

the most difficult to define and is also one of the most controversial. There

is however, a general agreement that intelligence refers to the overall

faculties of the mind which concern themselves with the sorting of information

in the brain after it has been received by the senses, the perceiving of

relationships between this new data and information which is already in memory,

and the capacity to make rapid and appropriate decisions as a result of the

previous processes.

The intellectual faculties of the brain are dynamic and interactive and

relate to the capacity of the central nervous system to respond speedily and

appropriately in a rapidly changing and potentially threatening environment.

Raymond J. Corsini provides us with a somewhat more simplistic

definition of the term intelligence. According to Corsini (1984) the term

intelligence can be employed to indicate the amount of knowledge available and

the rapidity with which new knowledge is acquired; the ability to adapt to new

situations and to handle concepts, relationships, and abstract symbols.

While the heredity/environment topic continues to be a controversial

issue, a great deal of evidence has been gathered to support both arguments.

In order to investigate the topic of nature/nurture it is important to

consider a variety of research elements. Among these elements are some of the

most relevant issues pertaining to this subject including: twin, adoption,

family, orphanage life, IQ, and race studies. It is to these studies we will

now turn our attention.

TWIN STUDIES

The importance of twin studies is evident if we look at the studies

objectively, if intelligence is basically hereditary, identical twins who have

the same genetic legacy, should be concordant for that trait than are fraternal

twins, which are no more alike genetically than other siblings.

Burt's (1958) famous study show that the intelligence test scores of

identical twins, whether reared together or apart , display considerably higher

correlation than the scores of fraternal twins.

Burt's work is currently viewed with caution due to the manner in which

he gathered and interpreted his data (Vernon, 1979). However, Burt's research

provides an important foundation for this research.

Jone's study (1946) shows that there is a modest difference in the

intelligence test scores of twins reared apart, and the more divergent the

environments, the greater the difference.

"While environmental factors are important in raising or lowering a

child's level of intellectual performance, these studies demonstrate that they

only do so within limits set by heredity." (Mussen, Conger, and Kagon, 1963

p.52)

The Louisville Twin Study (Wilson, 1983) showed that environmental

considerations such as characteristics of home and the interaction of the mother

with the infant, have a prominent effect upon the infant's mental development.

Vermon (1979) concludes that we may attribute 60 percent of the

determination of IQ status to heredity, 30 percent to environment and 10 percent

tot he combined effects of the two.