INTRODUCTION

The nature-nurture controversy has been one that has plagued psychology for

decades and till today, still remains a controversy. the term ‘nature-nurture’ is a colloquial

term for the two views of human development; one emphasizing heredity and the other

environment. it is the scientific, cultural and philosophical debate about whether human

culture, behaviour and personality are caused primarily by nature or nurture. in this regard,

nature is often defined as genetic or hormone-based behaviours while nurture is defined as

environment and experience.

The nature-nurture controversy relates to the relative importance of an individual’s

innate qualities (“nature” in the sense of nativism or innatism) as compared to an

individual’s personal experiences (“nurture” in the sense of empiricism or behaviourism)

in causing individual differences especially in behavioural traits.

The nature-nurture controversy is an age-old dispute among behavioural

psychologists, philosophers, theologians, and theorists of consciousness as to the source of

the creation of human personality: Does it develop primarily from biology (nature), or

from the environments in which we are raised (nurture)? People have been pondering the

role of nature and environment since the time of Hippocrates (c. 460-c. 377 B.C.). He, for

instance, linked human behaviour to four bodily fluids, or humours: yellow bile, blood,

black bile, and phlegm. Hippocrates classified personalities into four types related to these

four humours: choleric (yellow bile), or hot-tempered; sanguine (blood), or confident;

melancholic (black bile), or moody; and phlegmatic, or slow to take action.

Unlike Hippocrates, the philosopher John Locke (1632-1704), whose ideas were a

precursor to behaviourism, believed that behaviours were externally determined. Similarly,

the philosopher Jean-Jacques Rousseau (1712–1778) theorized that people were born

essentially good, and that positive aspects of the environmental contribute to the

development of behaviour. Locke believed that people were born essentially blank, like a

blackboard, and who they "became" was entirely the result of their experiences.

The first scientist of the modern era to seriously consider the genetic and

environmental effects in personality development was Sir Francis Galton, a wealthy

British scientist. He dabbled in the arts and sciences but became primarily interested in

what we today call genetics after his cousin, Charles Darwin, published The Origin of the

Species in 1859. He was fascinated by the idea of genetic pre-programming and-sought to

uncover the ways in which humans are predestined. Many of his experiments were

eccentric and ill-conceived, but his contributions to the field are still considered vital. His

studies, curiously, led to the development of the science of fingerprinting and to the

concept of the word association test. He also coined the term "eugenics" and believed that

science would one day be able to direct, with absolute precision, the development patterns

of human evolution. Taking the other position in this early debate was John Watson, the

eminent behaviourist who once made the outlandish claim— which he later modified—

that he could turn babies into any kind of specialist he wanted.

Over the years, much research has been done in the nature/nurture controversy, and

today nearly everyone agrees that both nature and nurture play crucial roles in human

development. This outlook has come to be known as interactionism and is the dominant

system of belief among biologists, psychologists, and philosophers nearly everywhere.

WHAT IS NATURE?

Nature refers to effect of the genes or hormones on behaviours. It refers to the

relative importance of an individual’s innate qualities (“nature” in the sense of nativism or

innatism) in causing individual differences especially in behavioural traits. According to

Sir Francis Galton, nature is all that a man brings with himself into the world

Nature was attributed to influence behaviours in the 17th century by the French

philosopher René Descartes when he set out views which held that we all, as individual

Human Beings, possess certain in-born ideas that underpin our approach to the world.

Also, the French philosopher Jean Jacques Roseau considered genetic factors as most

influential in behaviour formation.

In recent years, the nature side have of the debate have gained more attention with

headlines trumpeting newly discovered genes for virtually every behaviour. Evolutionary

psychology and socio-biology are two branches of science that attempt to demonstrate the

evolutionary roots of human behaviour. Scientists working on the Human Genome Project

recently discovered an estimated 100,000 genes in the DNA. They have been able to

identify genes responsible for varieties of diseases including Huntington Disease, Cystic

Fibrosis, Down syndrome, Tay - Sachs disease and a number of cancers.

Also, a new scientific study of 409 pairs of gay brothers by the NorthShore

Research Institute in the US found clear links between male sexual orientation and two

specific regions of the human genome with the lead scientist Alan Sanders declaring that

the work “erodes the notion that sexual orientation is a choice.”

Another area that has favoured the nature side of the debate is twins study. The

behavioural genes are somewhat proven to exist when we take a look at fraternal twins.

When fraternal twins are reared apart, they show the same similarities in behaviour and

response as if they have been reared together.

Nature or genetics has been proven to be an important factor in the development of

some mental health conditions such as schizophrenia, bipolar and major depression.

Another area where researchers may place more emphasis on nature more than nurture is

that of addictions. Studies show that alcohol addiction can recur in families and that

certain genes may have an influence over the way alcohol tastes and the way it affects the

body.

Below is a table showing behaviours that are strongly influenced by nature.

Physical

Characteristics

Intellectual

Characteristics

Emotional

Characteristics

Height Memory Shyness

Obesity Age of language

acquisition

Neurotic

Weight Ability as

measured by IQ

test

Extraversion

Tone of voice Reading Anxiety

disability

Blood pressure Mental

retardation

Alcoholism

Tooth decay ----------------- Schizophrenia

Athletic ability ------------------- ----------------------

Age of death -------------------- ----------------------

Source: Feldman (1996), Understanding Psychology

WHAT IS NURTURE?

Nurture refers to an individual’s personal experiences in causing individual

differences especially in behavioural traits. It is seen as the development of behaviours as

a result of as environment and experience.

In his work English Men of Science: Their Nature and Nurture, which discussed the

influence of genetics and environment on a person's development and which was

originally published in 1874, Francis Galton, a second or half-cousin to Charles Darwin

stated: "...nurture is every influence that affects man after his birth." 

The view that humans acquire all or almost their behavioural traits from nurture was

termed tabula rasa (blank slate) by John Locke in 1690.

J.B Watson in the 1920s and 30s established the purist school of behaviourism. He was

convinced of the complete dominance of cultural influence over anything heritability

might contribute, to the point of claiming:

“Give me a dozen healthy infants, well-formed and my own

specified world to bring them up in and I’ll guarantee to take any

one at random and train him to become any type of specialist I might

select- doctor, lawyer, artist, merchant-chief and, yes, even a beggar

and a thief, regardless of his talents, penchants, tendencies, abilities,

vocations and race of his ancestors.”

This view was widely held during much of the 20th century that in the 1960s, researcher

John Money attempted to demonstrate that gender was a product of early conditioning by

raising a boy, whose circumcision was botched, as a girl. His experiment seemed

successful in the beginning but was ultimately a failure.

Certain genetic factors may create a predisposition for a particular illness but the

probability that a person develops that illness depends in part on environment (nurture).

This is evident in James Fallon, a neuroscientist who discovered that he had the brain of a

psychopath. He stated that he believes growing up in a nurturing and loving environment

helped him to become a successful adult and may have been effective at preventing him

from fully developing traits of psychopathy. Similarly, the basis for addiction is not

thought to be entirely genetic by most researchers. Environmental aspects such as the

habits of parents, friends, or a partner might also be a significant factor contributing to the

development of an addiction.

WHICH THEN DO YOU CONSIDER TO INFLUENCE BEHAVIOUR MORE?

According to Donald Hebb, “The question of nature or nurture, which contributes

more to personality, is like asking which contributes more to the area of a rectangle; its

length or its width”.

However, from my point of view and for the purpose of this assignment, I strongly

consider nurture to influence behaviour more. My reasons are as follows:

Firstly, Heritability (nature) is subject to environment (nurture). This is because

environmental inputs affect the expression of genes (epigenetics).

Secondly, researchers at the University of Liverpool recently found that while a

family history (genetics or nature) was the second strongest predictor of mental illness, the

strongest predictor was in fact life events and experiences (nurture) such as childhood

bullying, abuse or other trauma, thereby, supporting the significant role of nurture in

mental health issues.

Thirdly, Anthropologist Donald Brown in the 1980s surveyed hundreds of

anthropological studies from around the world and collected a set of Cultural Universals.

He identified approximately 150 such features coming to the conclusion that there is

indeed a “Universal human nature” and that these features points to what that universal

human nature is. This ultimately implies that nurture is a basic composition of the human

nature.

Moreover, while certain types of behaviour can be traced to certain genetic

characteristics, there is no genetic blueprint to an individual’s personality. Implicitly

implying that nurture is what determines a person’s personality.

Further more, Environment is necessarily an important factor in any developmental

process, including that of the prenatal period. In the case of motor skills, for example,

development can be accelerated or retarded by the presence or absence of environmental

stimulation. In a foundling home in Lebanon, where children spent most of their first year

lying on their backs in cribs, totally ignored by adults, motor skills were so retarded that

some infants over a year old could not sit up, let alone walk (Dennis and Sayegh, 1965).

While a poor environment retards development, additional experience and stimulation can

encourage some motor skills provided the stimulation is appropriate to the baby's age.

Another study has shown that when babies are trained to use their walking reflex

regularly, they begin to walk about one to two months earlier than most other infants

(Zelazoetal, 1972). Stimulation from the environment not only enhances muscle strength

but also facilitates the development of the nervous system. During sensitive periods of

development, an organism is especially susceptible to certain kinds of environmental

influences.

Finally, behavioural genetics assumes that the genetic bases of an individual’s

behaviour simply cannot be determined. This shows that genetics (nature) does not

determine a person’s behaviour but rather, nurture does.

REFERENCES

James Vincent (Nov 21, 2014). Science. Largest ever study into the gay gene ‘erodes

the notion that sexual orientation is a choice.’ The Independent. Retrieved

from http://www.independent.co.uk/news/science/largest-ever-sudy-into-the-

gay-gene-erodes-the-notion-that-sexual-orientation-is-a-choice9875855.html

Lemma, Girma(2005). Lecture notes for health science students: General Psychology.

Ethiopia: Defence University College.

Nature-Nurture controversy (2015). Retrieved online 12th Jan, 2016 from

/http://psychology.jrank.org/pages/442/Nature-Nurture/

Nature vs. Nurture Debate (2014). Retrieved online 12th Jan 2016 from

/http://goodtherapy.org/blog/psychpedia/nature-versus-nurture/

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