GENERAL PSYCHOLOGY
Chapter 2: Determinants of Behaviour
INTRODUCTION
- Behaviour has varied explanations.
- Example: The failure of a child in school may be explained in two different ways:
The child is dull and therefore incapable of learning anything, which is difficult.
The child is bright enough, but is uninterested, or lazy, or poorly trained.
- The first explanation refers to the native equipment, to the inborn capacity.
- The second explanation refers to the lack of development on one’s inborn abilities through
environmental factors.
- The distinction of these two is commonly called HEREDITY (Nature) and ENVIRONMENT
(Nurture).
HEREDITY
- Comprises the totality of influences, biologically transmitted from the parents to the offspring
that determines the ways in which an individual will make use of his environment.
- It covers all the factors that were present in the individual at the time of conception.
ENVIRONMENT
- Is the sum total of all external conditions and factors that are capable of influencing an
organism.
- It covers all the external factors that have acted on him after conception.
IMPACT OF BOTH DETERMINANTS
The pervasive influence of Heredity
In animals
- Selective breeding (a particular group of organisms is continuously mated
with each other) leads after some generations to two quite distinct groups
of organisms.
- By keeping environmental factors constant, the difference has to be
attributed to the hereditary factors.
In human being
- The “Martin Kallikak” natural experiment.
- Martin Kallikak is a soldier in the American Revolution, was the father of
an illegitimate boy by a feeble - minded mother. From this boy there have
been 480 descendants, of whom 143 were abnormal (mentally retarded,
defective personalities), 291 are barely normal, and only 46 were
considered normal. After the revolution, Martin married an intellectually
superior woman of his own social level and thereby founded a normal
Chapter 2: Determinants of Behaviour
INTRODUCTION
- Behaviour has varied explanations.
- Example: The failure of a child in school may be explained in two different ways:
The child is dull and therefore incapable of learning anything, which is difficult.
The child is bright enough, but is uninterested, or lazy, or poorly trained.
- The first explanation refers to the native equipment, to the inborn capacity.
- The second explanation refers to the lack of development on one’s inborn abilities through
environmental factors.
- The distinction of these two is commonly called HEREDITY (Nature) and ENVIRONMENT
(Nurture).
HEREDITY
- Comprises the totality of influences, biologically transmitted from the parents to the offspring
that determines the ways in which an individual will make use of his environment.
- It covers all the factors that were present in the individual at the time of conception.
ENVIRONMENT
- Is the sum total of all external conditions and factors that are capable of influencing an
organism.
- It covers all the external factors that have acted on him after conception.
IMPACT OF BOTH DETERMINANTS
The pervasive influence of Heredity
In animals
- Selective breeding (a particular group of organisms is continuously mated
with each other) leads after some generations to two quite distinct groups
of organisms.
- By keeping environmental factors constant, the difference has to be
attributed to the hereditary factors.
In human being
- The “Martin Kallikak” natural experiment.
- Martin Kallikak is a soldier in the American Revolution, was the father of
an illegitimate boy by a feeble - minded mother. From this boy there have
been 480 descendants, of whom 143 were abnormal (mentally retarded,
defective personalities), 291 are barely normal, and only 46 were
considered normal. After the revolution, Martin married an intellectually
superior woman of his own social level and thereby founded a normal
