biological approach psyb1. basic assumptions of the biological approach mind and behaviour have a...

Biological Approach

PSYB1

Basic Assumptions of the Biological Approach Mind and behaviour have a biological basis e.g. the mind

is a result of the way that the brain works. Changing the structure or function of the nervous system

will change behaviour and/or the mind. Behaviour and the mind have evolved e.g. they are

inherited as a result of the action of the genes. To understand mind and behaviour we have to

understand the nervous system and inheritance of characteristics.

Methods of studying brain function Scanning (PET/CAT/MRI) EEG Case studies Post mortem examination of brain Laboratory experiments

Navigation Related Structural Change in Taxi DriversMaguire et al (2000) Taxi drivers given brain scans by

scientists at University College London had a larger hippocampus compared with other people. This is a part of the brain associated with navigation in birds and animals.

The scientists also found part of the hippocampi grew larger as the taxi drivers spent more time in the job.

MRI of Hippocampus

Looking at effects of brain damage from accident, illness or surgery.

Selective Breeding

The intentional breeding of organisms with desirable trait in an attempt to produce offspring with similar desirable characteristics or with improved traits. E.g. Rats have been

selectively bred for intelligence.

Twin and family studies

Tyron (1942)

Exposed a genetically diverse set of rats to a maze. Bred those who made few errors and those who

made many errors together.E.g. MB+MB; MD+MD

Over seven generations the rats made fewer and fewer or more and more errors.

Demonstrated that maze learning could be inherited.

Comparative Psychology

Compares animal physiology and behaviour to humans in order to achieve a better understanding. E.g. Harlow’s studies on the effect of maternal deprivation on infant

monkeys.

Effect of Separation on Infant Monkeys (1958) Is food or comfort the

main driver for attachment?

Infants spent more time on the towelling model.

Biological approach uses a lot of animals in studies, but can we apply our findings to

people? Humans are similar to other mammals: share

DNA and have similar nervous systems – we can apply findings.

Humans are different: more highly developed nervous system, have society, culture, language and creativity – we shouldn’t apply findings.

Evolution & Psychology

Evolutionary psychology regards humans as subject to same evolutionary processes as other animals (continuity)Assumes that behavioural characteristics can

be inherited just like physical onesTries to explain human behaviour/psychology

in terms of evolutionary processes

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Evolution

Each living thing (organism) has a set of characteristics encoded by its genes

The organism inherits its genes from its parent(s)

Variations between organisms are caused by variations in the genotype

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Genotype and Phenotype

Genotype: the genetic material that an individual has. Fixed. Inherited. E.g. potential height

Phenotype: how that genetic material is expressed. Variable. Influenced by environment – diet, toxins.E.g. actual height

Evolution

An organism’s ability to survive depends on how well its characteristics allow it to:Exploit the opportunities available in its

environmentAvoid or deal with the threats presented by its

environment We call this the organism’s fitness

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Fitness

Yummy!

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Arse.Arse.Oops!

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Evolution

Fit organisms are more likely to survive into adulthood than unfit ones.Consequently, they are more likely to mate and

have offspringThey pass on their genes to the next generation

Gradually, the genes for successful characteristics spread through the population

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Why are we attracted to particular types of faces?

Youth + symmetry, skin, eyes = health

Jocelyn Wildenstein has spent $4million on cosmetic surgery.

Inheritance & Biological Structures

The biological approach assumes that genes encode for the structure and function of the nervous system.

This means that behaviour (e.g. phobias) that has evolved has a biological basis. Our brains function so that, for example, most of us keep away from spiders.

Evolution of Psychological Characteristics:

Why are people afraid of spiders?

Afraid of Spiders

Not afraid of Spiders

Keeps away from spiders

Does not keep away, gets bitten and dies

Survives and passes on genes

Dies and does not pass on genes

Evaluation of the biological approach Copy out the table on page 5 of your textbooks

into your notes n.b.: Bi-polar disorder is a mental illness causing swings

between extreme depression and mania. Nature-Nurture debate is the extent to which our

characteristics are inherited (nature) or acquired (nurture).

Look up the definition of the term reductionist on page 61 and write it in your notes so that you understand it.

Environment

Environment contains a range of opportunities and threats (e.g. food

sources, predators)

Evolution

Organism

Organism has particular

characteristics determined by its

genes

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HWK page 30

State, explain, application For example we can study the brain’s

activity during a language task to identify the areas that are involved. This means that we can predict the effects of any damage on language.