The Biological Approach
The biological approach suggests that everything psychological is at first biological, in order to
understand human behaviour we need to look at biological structures and processes within
the body.
Evolution and Behaviour
Charles Darwin argued that over time we adapt to our environment through biological evolution.
This refers to the changes that take place in the characteristics of a population over time.
Evolution: The gradual change in inherited characteristics of a species over time.
Natural selection: Any genetically determined behaviour that enhances an individual’s ability
to survive and reproduce will continue in future generations and gradually become more
widespread over time.
Giraffe example:
Giraffes originally had short necks, but they evolved to have long necks. This is because ones with
short necks couldn’t reach the leaves from the trees to eat, so they died out. Long-necked giraffes
had a survival advantage and reproduced, passing on their genes to their offspring.
Buss (1989) studied 37 different cultures and found universal similarities in human mate
preferences.
- Women desired mates with resources.
- Men desired young physically attractive women (an indicator of their fertility and
reproductive values).
The Influence of Genes on Behaviour
Hereditary characteristics from parents are passed on through our genes and this is why both
physically and psychologically we take things from our parents.
Behaviour geneticists' study whether behavioural characteristics such as intelligence or our
temperament are inherited, much like our physical attributes e.g., height or eye colour.
Twin studies have been used to assess the genetic basis of behaviour by comparing
concordance rates. If identical twins (monozygotic / MZ) have higher concordance rates than
non-identical twins (dizygotic / DZ) this would suggest a genetic basis to the behaviour, as MZ
twins share 100% of the same genes.
Hereditary: The passing of characteristics from one generation to the next.
Concordance Rates: The extent to which both twins share the same characteristics.
, Genotype: The genetic makeup of an individual.
The genotype is a collection of genetically inherited material that is written in the DNA of an
individual’s cells.
Phenotype: The observable characteristics of an individual.
The phenotype is the physical appearance that is a result of this inherited information.
The Influence of Biological Structures on Behaviour
The nervous system is comprised of several connected systems:
- Central Nervous System – Brain and spinal cord
- Peripheral Nervous System – Somatic (sensory and motor) and autonomic nervous
system (eyesight/digestion/heart and breathing etc.)
The nervous system carries a message from one part of the body to another, using individual nerve
cells known as neurons.
Neurons transmit nerve impulses in the form of electrical impulses. Many aspects of our
behaviour are controlled by neurons, e.g., breathing, eating and our sexual behaviour.
Brain Lobes
Frontal lobe: speech, thought and learning
Temporal lobe: hearing and memory
Parietal lobe: processes sensory information
Occipital lobe: visual information
Hormones
Hormones are chemicals that are produced by our endocrine glands (such as the pituitary gland)
which together make up the endocrine system.
In response to a signal in the brain, hormones are secreted directly into the bloodstream by the
endocrine glands where they travel up to their target cell and stimulate receptors on the target
cell.
The presence of the hormone causes a physiological reaction in the cell, altering its activity.
The Influence of Neurochemistry on Behaviour
When a nerve impulse reaches the end of one neuron, a neurotransmitter (hormone) is released.
There are many different types of neurotransmitters. Some trigger the receiving neuron to send an
impulse, and some stop them.
The biological approach suggests that everything psychological is at first biological, in order to
understand human behaviour we need to look at biological structures and processes within
the body.
Evolution and Behaviour
Charles Darwin argued that over time we adapt to our environment through biological evolution.
This refers to the changes that take place in the characteristics of a population over time.
Evolution: The gradual change in inherited characteristics of a species over time.
Natural selection: Any genetically determined behaviour that enhances an individual’s ability
to survive and reproduce will continue in future generations and gradually become more
widespread over time.
Giraffe example:
Giraffes originally had short necks, but they evolved to have long necks. This is because ones with
short necks couldn’t reach the leaves from the trees to eat, so they died out. Long-necked giraffes
had a survival advantage and reproduced, passing on their genes to their offspring.
Buss (1989) studied 37 different cultures and found universal similarities in human mate
preferences.
- Women desired mates with resources.
- Men desired young physically attractive women (an indicator of their fertility and
reproductive values).
The Influence of Genes on Behaviour
Hereditary characteristics from parents are passed on through our genes and this is why both
physically and psychologically we take things from our parents.
Behaviour geneticists' study whether behavioural characteristics such as intelligence or our
temperament are inherited, much like our physical attributes e.g., height or eye colour.
Twin studies have been used to assess the genetic basis of behaviour by comparing
concordance rates. If identical twins (monozygotic / MZ) have higher concordance rates than
non-identical twins (dizygotic / DZ) this would suggest a genetic basis to the behaviour, as MZ
twins share 100% of the same genes.
Hereditary: The passing of characteristics from one generation to the next.
Concordance Rates: The extent to which both twins share the same characteristics.
, Genotype: The genetic makeup of an individual.
The genotype is a collection of genetically inherited material that is written in the DNA of an
individual’s cells.
Phenotype: The observable characteristics of an individual.
The phenotype is the physical appearance that is a result of this inherited information.
The Influence of Biological Structures on Behaviour
The nervous system is comprised of several connected systems:
- Central Nervous System – Brain and spinal cord
- Peripheral Nervous System – Somatic (sensory and motor) and autonomic nervous
system (eyesight/digestion/heart and breathing etc.)
The nervous system carries a message from one part of the body to another, using individual nerve
cells known as neurons.
Neurons transmit nerve impulses in the form of electrical impulses. Many aspects of our
behaviour are controlled by neurons, e.g., breathing, eating and our sexual behaviour.
Brain Lobes
Frontal lobe: speech, thought and learning
Temporal lobe: hearing and memory
Parietal lobe: processes sensory information
Occipital lobe: visual information
Hormones
Hormones are chemicals that are produced by our endocrine glands (such as the pituitary gland)
which together make up the endocrine system.
In response to a signal in the brain, hormones are secreted directly into the bloodstream by the
endocrine glands where they travel up to their target cell and stimulate receptors on the target
cell.
The presence of the hormone causes a physiological reaction in the cell, altering its activity.
The Influence of Neurochemistry on Behaviour
When a nerve impulse reaches the end of one neuron, a neurotransmitter (hormone) is released.
There are many different types of neurotransmitters. Some trigger the receiving neuron to send an
impulse, and some stop them.
