environment (Visscher, 2012).
Hence, by comparing the experiences of identical twins with those of fraternal twins, who
come from separate eggs and share on average half their DNA, researchers can genuinely
quantify the extent to which one’s life is affected by the genetic factors. A critical aspect of
this study is that determine the heritability of some specific ailments or diseases. In this
case, if identical twins are similar to each other concerning psychopathology than fraternal
twins are, then vulnerability to the disease must be entirely or partially domiciled in
heredity.
These two studies of the differences between identical twins to pinpoint the influence of
environment and comparing identical twins with fraternal ones to measure the role of
hereditary factors have been very important in understanding the interaction between
nature and nurture in determining our personalities, behaviour, and vulnerability to disease.
8
PSYC6113-18W-O-3C Nature Versus Nurture: An Age-old Debate
UNDERSTANDING THE IMPACT OF NURTURE ON PERSONALITY
Nurture comprises all the variable environmental factors that impact whom one becomes right
from early childhood experiences such as how one was reared, our social interactions, and socio-
cultural influences.
Dr. John Locke was an English philosopher and physician who first defined human characters
and traits through the dynamics of a continuity of consciousness. Dr. Locke proposed the theory
that the mind was a blank slate or
tabula rasa
at birth. He claimed that individuals are born
without any innate knowledge, thus contradicting Plato´s theory.
Though not discounting that genetic influences may exist, proponents of the nurture theory
believe that nature does not have a significant impact on traits, and also that one’s behavioural
expression come only from the type of environment we were raised.
Some studies on infant and
child temperament have revealed the most critical evidence supporting nurture theories
(
Visscher, 2012)
.
As previously mentioned, the American psychologist John Watson, best known for his
controversial but elucidating experiments with a young orphan named Little Albert,
showed that the acquisition of a phobia could be explained through classical
conditioning. John Watson as a strong proponent of environmental learning once said:
"
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... regardless of his talents, penchants, tendencies, abilities,
vocations and race of his ancestors." (
Traynor, 2010)
.
9
PSYC6113-18W-O-3C Nature Versus Nurture: An Age-old Debate
A significant scholarly work published by faculty at the Twin Research and Genetic
Epidemiology unit at St. Thomas' Hospital in London in 2000, titled
Happy Families: A
Twin Study of Humour
; proposes that a sense of humour is a learned trait, influenced by
family and cultural environment, and not genetically determined.
