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 Drivers Maguire 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.breedingorganismstrait offspring  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 ones  Tries to explain human behaviour/psychology in terms of evolutionary processes

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

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 environment  Avoid or deal with the threats presented by its environment We call this the organism’s fitness

Fitness Yummy!

Arse. Oops!

Evolution Fit organisms are more likely to survive into adulthood than unfit ones.  Consequently, they are more likely to mate and have offspring  They pass on their genes to the next generation Gradually, the genes for successful characteristics spread through the population

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

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.