The document discusses the nature vs nurture debate in human development. It provides background on the long-standing controversy between the influence of innate qualities ("nature") versus personal experiences ("nurture"). While early theorists leaned towards one side, modern science recognizes an interaction between both. Nature includes genetic and hormonal influences, while nurture encompasses environmental and experiential factors. The document examines evidence for both positions and concludes that nurture has a stronger influence on behavior, since environmental inputs can affect gene expression, life experiences are strong predictors of mental illness, and behavior is not solely determined by genetics.

1. 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.

2. 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.

3. 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.”

4. 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

5. Tone of voice Reading
disability
Anxiety
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.

6. 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.

7. 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.

8. 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.

9. REFERENCES
James Vincent (Nov 21, 2014). Science. Largesteverstudy into the gay gene ‘erodes
the notion that sexualorientation 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:GeneralPsychology.
Ethiopia: Defence University College.
Nature-Nurture controversy(2015). Retrievedonline 12th
Jan, 2016 from
/http://psychology.jrank.org/pages/442/Nature-Nurture/
Nature vs. Nurture Debate (2014). Retrievedonline 12th
Jan 2016 from
/http://goodtherapy.org/blog/psychpedia/nature-versus-nurture/
Wikipedia, the free encyclopaedia