The biological approach:

Question 1

Biological approach

Answer 1

Views humans as biological organisms and so provides biological explanations for all aspects of psychological functioning.

Question 2

Gene:

Answer 2

A part of the chromosome of an organism that carries information in the form of DNA.

Question 3

Genotype:

Answer 3

The genetic make-up of an individual.
The genotype is a collection of inherited genetic material that is passed from generation to generation

Question 4

Natural selection:

Answer 4

The process by which inherited characteristics that enhance an individual’s reproductive success (or ‘fitness’) are passed onto the next generation, and so become more widespread in the population over time.

Question 5

Phenotype:

Answer 5

The observable characteristics of an individual.
This is a consequence of the interaction of the genotype with the environment.

Question 6

BIOLOGICAL INFLUENCES ON BEHAVIOUR
The influence of genes on behaviour:

Answer 6

Genes: the mechanisms of heredity:

Genotype and phenotype:

The genetic basis of behaviour:

Question 7

Genes: the mechanisms of heredity:

Answer 7

Heredity is the passing of characteristics from one generation to the next through the genes, and is the reason why offspring take after’ their parents in terms of psychological characteristics.
Genes carry the instructions for a particular characteristic (such as intelligence or temperament), but how this characteristic develops depends partly on the interaction of the gene with other genes, and partly on the influence of the environment.
The extent to which a psychological characteristic is determined by genes or environment is called the nature-nurture debate.

Question 8

Genotype and phenotype:

Answer 8

There is an important difference between the genotype - the genetic code that is ‘written in the DNA of an individual’s cells - and the phenotype, which is the physical appearance that results from this inherited information.
Whilst we might expect a direct relationship between the two, this is not always the case.
For example, in the case of eye colour, someone may inherit a recessive gene for blue eyes, but this will not be expressed if they have also inherited a dominant gene for brown eyes from the other parent.
In this case, we cannot determine the genotype (one blue eyes gene, one brown eyes gene) from just observing the phenotype (i.e. brown eyes).

Question 9

The genetic basis of behaviour:

Answer 9

Each individual possesses a unique combination of genetic instructions, therefore we differ from each other in terms of personality, intelligence, abilities and so on.
The term heritability refers to the amount of variability in a trait within a population that can be attributed to genetic differences between’ individuals within that population.
The more that a trait is influenced by genetic factors, the greater its heritability.
For example, studies of identical twins have suggested that the variation in individual intelligence - what makes one person more intelligent than another - could be 60-80% due to genes.

Question 10

The influence of biological structures on behaviour

Answer 10

Neurons and the nervous system

The brain:

Question 11

Neurons and the nervous system:

Answer 11

The central nervous system (CNS) comprises the brain and spinal cord.
The peripheral nervous system (PNS) comprises the somatic and autonomic nervous systems.

The nervous system carries messages from one part of the body to another using individual nerve cells known as neurons.
Neurons transmit nerve impulses in the form of electrical signals. Many aspects of behaviour are under neuronal control, including breathing, eating and sexual behaviour.

Question 12

The brain:

Answer 12

The largest part of the brain is the cerebrum, making up about 85% of the total mass of the brain.
The outer surface of the cerebrum is called the cerebral cortex, which is responsible for many of the ‘higher-order’ functions such as thought and language.
The cerebrum is divided into two halves (known as hemispheres), with each hemisphere further divided into four different parts (known as lobes)

Question 13

The influence of neurochemistry on behaviour

Answer 13

Neurotransmitters:

Evolution and behaviour:

Hormones:

Question 14

Neurotransmitters

Answer 14

When a nerve impulse reaches the end of one neuron, a chemical called a neurotransmitter is released It travels from one neuron to the next across a junction called the synapse.
There are many different types of neurotransmitter, some of which trigger the receiving neuron to send an impulse and some stop it from doing so.
Those neurotransmitters that trigger nerve impulses in the receiving neuron and stimulate the brain into action are called excitatory neurotransmitters.
Those that inhibit nerve impulses in order to calm the brain and balance mood are called inhibitory neurotransmitters
Dopamine is an excitatory neurotransmitter that is associated with our drive or motivation.
Serotonin is an inhibitory transmitter, adequate amounts of which are necessary to maintain a stable mood.
For example, Crockett et al. (2008) found that when serotonin levels are low people tend to display increased aggression.

Question 15

Evolution and behaviour

Answer 15

Charles Darwin argued that, over time, organisms become adapted to their environment through biological evolution.
This refers to the changes that take place in the characteristics of a population over time.
The mechanism behind biological evolution is natural selection.
Individuals within a species differ from each other in terms of their physical characteristics and in their behaviour, and at least some of this variation is inherited.
Because individuals must compete with each other for access to resources (mates, food, etc.), those who survive this competition and go on to reproduce will tend to have behaviours that are more likely to lead to survival and reproductive success than those who do not.
These behaviours will be passed on to offspring and will become more widespread in the population; through the process of natural selection, successive generations will develop behaviours that are even more likely to lead to survival and reproductive success.
Buss (1989) studied 37 different cultures and found universal similarities in human mate preferences.
Women desired mates with resources (to provide for offspring) whilst men desired young, physically attractive women (an indication of their fertility and reproductive value).

Question 16

Hormones:

Answer 16

Hormones are chemicals that are produced by endocrine glands such as the pituitary gland, which together make up the endocrine system.
In response to a signal from the brain, hormones are secreted directly into the bloodstream by the endocrine glands, where they travel to their ‘target cells’ and exert their influence by stimulating receptors on the surface of or inside cells.
The presence of a hormone causes a physiological reaction in the cell, altering its activity
For example, Carré et al. (2006) studied a Canadian ice hockey team over the course of a season.
They found evidence of a surge in levels of the hormone testosterone whenever the team played in their home stadium, suggesting the hormone energised the players to defend their home territory.

Question 17

EVALUATION/DISCUSSION

Answer 17

The importance of the scientific method

Applications of the biological approach:

The biological approach is reductionist

Question 18

The importance of the scientific method:

Answer 18

The biological approach uses the scientific method, particularly the experimental method, as its main method of investigation.
Experimental studies take place in highly controlled environments so that other researchers are able to replicate research studies under the same experimental conditions, adding to the validity of the original findings if they can be reproduced.
The use of sophisticated imaging and recording techniques has increased the precision and objectivity of experimental research in this area.
As a result, these techniques have contributed to the scientific validity of the biological approach.

Question 19

Applications of the biological approach

Answer 19

A strength of the biological approach is that it provides clear predictions, e.g. about the effects of neurotransmitters on behaviour or the influence of biological rhythms on behaviour.
This has led to significant applications of biological research in the real world.
Research into the role of neurochemical imbalance in depression has led to the development of effective drug treatments.
Likewise, research into circadian rhythms and their effect on psychological well-being has led to significant improvements in the working conditions of shift workers.
This further demonstrates the value of adopting a biological approach to the study of human behaviour

Question 20

The biological approach is reductionist:

Answer 20

The biological approach is criticised for its belief that complex behaviour can be broken down into the action of genes, neurochemicals and hormones.
For example, many explanations of mental disorders are reductionist because genes or neurochemical imbalances are believed to be the main cause of these disorders.
However, whilst a reductionist approach lends itself to scientific investigation, we cannot fully understand a behaviour without also taking account of the other factors that influence it.
These include cognitive, emotional and cultural factors, all of which have a significant influence on behaviour.