1 of 42

Biological Approach

M20 Revision Session by chelsie#2995

2 of 42

Overview

3 of 42

Principles of Biological Approach

Behaviour is the product of physiology
Behaviour can be genetically inherited
Animal research may inform our understanding of human behaviour

4 of 42

Brain and Behaviour

5 of 42

Techniques to Study the Brain

Autopsies are an examination of the corpses for structural differences compared with the average (Broca 1861, “Tan”)
Selective Destruction means incision into selected brain tissue and observing its results (Scoville & Milner 1957, Patient HM)
Brain Imaging is the technique to directly/indirectly image the structure or function of the brain

Magnetic Resonance Imaging
Functional Magnetic Resonance Imaging
Computerized Axial Tomography
Positron Emission Tomography
Electroencephalogram
etc.

6 of 42

Magnetic Resonance Imaging

MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body.
Magnetic field causes nuclei in brain to emit varying radio waves, creating detailed images of organs and tissues
Radio signals from nuclei radio waves are processed into images showing different body tissues

7 of 42

Magnetic Resonance Imaging

Maguire et al. (2000) - London taxi driver
Corkin (1997) - HM Patient brain damage scan
Draganski et al (2004) - learning juggling

strengths	limitations
Non-invasive Little no-risk of harm High resolution (detailed) pictures are produced	Doesn’t indicate function-structural difference can’t be linked causatively to behaviours

8 of 42

Functional Magnetic Resonance Imaging

Measures brain activity by detecting blood flow changes. Further development of MRI, using magnetic waves to cause nuclei to emit radio waves.

Takes multiple snapshots, observing regions with rich and low oxygen-blood flow which indicates neural activity

The magnetic field causes the hydrogen atoms in the body’s cells to move

9 of 42

Functional Magnetic Resonance Imaging

Baumgartner et al. (2008) - oxytocin in the breaches of trust
Harris & Fiske (2006) - the role of the brain in prejudice
Sharot et al. (2007) - biological basis of flashbulb memory
Fisher, Aron, & Brown (2005) - dopamine on love

strengths	limitations
Non-invasive Little no-risk of harm Easy to carry out Can causatively indicate links between thinking and brain activity	Unnatural settings (behaviour/cognition can be artificial, not ecologically valid)

10 of 42

Brain imaging	Function	Data Gathered	Advantages	Disadvantages
MRI (Magnetic Resonance Imaging)	MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body. Magnetic field causes nuclei in brain to emit varying radio waves, creating detailed images of organs and tissues	Radio signals from nuclei radio waves are processed into images showing different body tissues	Non-invasive & little no-risk of harm High resolution (detailed) pictures are produced	Doesn’t indicate function-structural difference, can’t be linked causatively to behaviours
CAT (Computed Axial Tomography Scan)	Taking a number of x-rays of a particular section of the body from different angles	X-ray slices which shows the density of brain structures	Easy to carry out High resolution (detailed) pictures are produced	Slight risks are possible due to radiation exposed expensive
fMRI (Functional Magnetic Resonance Imaging)	Measures brain activity by detecting blood flow changes. Further development of MRI, using magnetic waves to cause nuclei to emit radio waves. Takes multiple snapshots, observing regions with rich and low oxygen-blood flow which indicates neural activity The magnetic field causes the hydrogen atoms in the body’s cells to move	Produces video representation of changes in which regions of the brain are active over a period of time	Non-invasive, little risk of harm, easy to carry out Can causatively indicate links between thinking & activity brain	Unnatural settings (behaviour/cognition can be artificial, not ecologically valid)

11 of 42

Brain imaging techniques	Function	Data Gathered	Advantages	Disadvantages
PET (Positron Emission Tomography)	Injected with radioactive isotope. The decaying isotope releases a positron, collides with electrons and forms gamma rays. These gamma rays are picked up by the PET scan	use radioactive tags to show which brain areas become active when someone performs a task	Person doesn’t have to remain still (can do activities/experiments while doing experiments)	Low scanning resolution Possible risk of harm (isotope consumption) Expensive
EEG (Electroencephalogram)	Looks at electrical activity of neurons that leads to synaptic release and the cellular communication that underlies computation in the brain.	Records brain electrical waves to detect abnormality, alertness or drowsiness (seizures, awake, asleep)	Easy to carry out and little risk to harm High resolution (greatly detailed)	It’s hard to look for spatial localization due to overflowing neuron activities

12 of 42

Localization

the functions of specific parts of the brain and how they relate to behaviour

behaviours are quite complex and involve several different parts of the brain. Although specific parts of the brain may have specific functions, they work together with other parts of the brain to create behaviours.

There are 3 main perspectives in concerns with Localization:

Strict localization
Specific functions are distributed
Relative Localization

13 of 42

Localization

Strict localization - theory that specific parts of the brain have specific functions that are related to specific behaviours

Maguire et al. 2000

Specific functions are distributed - Theory that memory is distributed, because principle of mass action and equipotentiality

Lashley (1929) - Cortex removal & Maze running in rats

Relative localization - Localizations of some functions under some condition but also acknowledges limitations of localization

Gazzaniga (1967) and Sperry (1968)

14 of 42

Neural Networks

a series of interconnected neurons where synapses connects one neuron to another carries out a specific function which is formed through dendritic branching

Neural networks can be shaped from neural pruning (pruning, then renewal of neurons) and neuroplasticity (from new environment stimulation)

(Maguire et al. 2000) - neural networks can carry out spatial navigation�(Draganski et al. 2004) - neural networks can support learning process

15 of 42

Neuroplasticity

Neurons are nerve cells that carry electrical impulses
Synapses allows a neuron to send electric or chemical signal to another neuron
How neuroplasticity works:

stimulation in the environment
neurons fire continually (in response to environment)
dendritic branching, where neurons sprout new dendrites
increases number of synapses available for the behaviour, forming neural networks
When there is no continuous stimulation of the environment, neural pruning may happen.

16 of 42

Neuroplasticity

brain's lifelong ability to reorganize itself by forming new neural connections through new experiences (an adaptation process)
allows neurons in the brain to compensate for injury and respond to changes in the environment.

(Maguire et al. 2000) - neuroplasticity can be observed in spatial navigation�(Draganski et al. 2004) - neuroplasticity in juggling

17 of 42

Neural Pruning

Neural pruning happens when the connection between two dendrites (synaptic connection) are lost
the brain thinks that the synaptic connections are no longer needed.

(Maguire et al. 2000) - Neural pruning can improve spatial navigation (reduced neurons for learning, increased retrieval for spatial navigation)�(Draganski et al. 2004) - neural pruning helps eliminate learned behaviour which aren’t rehearsed (juggling)

18 of 42

Neurotransmission

Neurotransmitter is a chemical substance released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse or junction, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure.

stored in the axon and released into the synaptic gap

19 of 42

Types of Neurotransmission

Excitatory: increase the chances a neuron will fire an action potential

Ex: acetylcholine, adrenaline, noradrenaline, dopamine, serotonin

Inhibitory: decrease the chances a neuron will fire an action potential

Ex: acetylcholine, dopamine

substances that bind to synaptic receptors:

Agonist: increase the effect of neurotransmitter

ex: nicotine (acetylcholine), cocaine (dopamine), citalopram (serotonin)

Antagonist: decrease the effect of neurotransmitter

ex: scopolamine (acetylcholine), chlorpromazine (dopamine),

20 of 42

Acetylcholine

important roles in cognitive function, majorly, in the neural mechanisms of memory. Involved in thought, learning & memory. Activates muscle action in the body. Also associated with action and awakening.

Rogers & Kesner (2003) - acetylcholine in memory formation

Excitatory: activates the hippocampus to form memory
Antagonist: scopolamine injected to rats

21 of 42

Serotonin

is known as a contributor to feelings of well-being and happiness, though its actual biological function is complex and multifaceted, modulating cognition, reward, learning, memory, and numerous physiological processes.

Crockett et al. (2010) serotonin on prosocial behaviour

Excitatory: increases prosocial behaviour
Agonist: citalopram (SSRI - selective serotonin reuptake inhibitor)

22 of 42

Dopamine

Helps control the brain's' reward and pleasure centres. Plays a key role in motivation; low levels are linked to addictive behaviour.

Fisher, Aron, and Brown (2005) - dopamine on romantic love

Excitatory: involved with motivation

23 of 42

Hormones and Behaviour

24 of 42

Hormones and Behaviour

body's chemical messengers
secreted by glands in the endocrine system
travel in bloodstream to tissues or organs
work slowly, over time, and affect many different processes, including growth and development

25 of 42

Types of Hormones

Cortisol
Serotonin
Adrenaline
Oxytocin
Testosterone
etc.

26 of 42

Cortisol

Secreted by the adrenal glands
helps control blood sugar levels, regulate metabolism, reduce inflammation
assist with memory formation.

Newcomer et al. (1999) - cortisol on verbal declarative memory

27 of 42

Serotonin

contributor to feelings of well-being and happiness
though its actual biological function is complex and multifaceted
Modulates on cognition, reward, learning, memory, and numerous physiological processes

Crockett et al. (2010) - serotonin on prosocial behaviour

28 of 42

Adrenaline

produced by the adrenal glands
plays an important role in flight or fight response
How it works:

brain senses fear
amygdala signals the release of adrenaline
stimulates the sympathetic nervous system
increased blood flow to muscles, heart rate and breathing rate
prepares an organism to either fight against a threat, or to run away from it.

Cahill & McGaugh (1995) - role of adrenaline and amygdala on memory

29 of 42

Oxytocin

produced in the hypothalamus
secreted by the pituitary gland
controls some human behaviors and social interaction
triggers the bond between a mother and an infant
may also play a role in recognition, sexual arousal, trust, and anxiety
Some research shows that the hormone may affect addiction and stress as well.

Baumgartner et al. (2008) - oxytocin in the breaches of trust

30 of 42

Pheromones and Behaviour

Pheromones is the general phenomenon that a chemical released by an animal can affect the physiology and behaviour of other animals within the species which often plays a role in

reproductive status (fertility)
sexual attractiveness.

Animals to detect pheromones through VNO (vomeronasal organ) and accessory olfactory bulb.
human pheromone has not been found yet, although there are putative (hypothesized) human pheromones

Wedekind et al. (1995) - smell in partner selection

31 of 42

Genetics and Behaviour

32 of 42

Genetics and Behaviour

unit of DNA usually located on a chromosome

controls the development of one or more traits
the basic physical and functional unit of heredity
genetic information is passed from parent to offspring

Wedekind et al. (1995) - MHC in partner selection

33 of 42

Genetics Similarities

human behavior is influenced by both nature & nurture
Ways to study genetic similarities:

Twin studies
Family studies
Adoption studies

34 of 42

Twin Studies

Compares estimates between MZ (monozygotic) twins and DZ (dizygotic twins) through concordance rates

MZ shares 100% of genotype (same egg)
DZ shares 50% of genotype (different eggs)
So if identical twins (MZ) are more similar than fraternal twins (DZ), that means there is genetic factors that takes place

Kendler et al. (2006) - moderate depression heritability�Bouchard and McGue (1981) - IQ correlations between relatives

35 of 42

Family Studies

Uses degrees of relatedness
Compares in a broader scale and across generations:

Siblings, parents, grandparents, cousins, etc.

Bouchard and McGue (1981) - IQ correlations between relatives

36 of 42

Adoption studies

Comparing adopted children to adoptive parents, biological parents, adoptive siblings and biological siblings

Kendler et al. (2015) - genetic environment on intelligence of the adopted

37 of 42

Evolutionary Explanations for Behaviour

humans have evolved to behave in ways that will increase the chances of survival (and thus passing on our genes)
The genetics that are passed on will influence our physiology in a way to promote adaptive behaviour

Wedekind et al. (1995) - MHC in partner selection

38 of 42

Animal Research [HL]

39 of 42

Animal Research

Animal research is not a research method

Studies using the technique of experimenting on animals (animal testing/research) may be used in biological research in psychology.

Rosenzweig, Bennet & Diamond (1972) - environmental stimuli on brain plasticity�Premack (2007) - animal teaching in comparison to human teaching�Shively & Day (2015) - stress on health

40 of 42

Animal Research

strengths	limitations
Humans and animals are identical in many ways (brain structure & genetically) Some useful models of behaviour came from animal experimentation Animal studies allow researchers to observe full lifespan (rats have 2-3yrs to live) Animal research can be highly controlled Inexpensive, easy to handle, easy to access, easy to manage	Animals and humans aren’t exactly the same Humans and animals may differ psychologically (Premack, 2007) Mice are used to test on drugs, even if never directly applied to humans Ecological validity due to experiment environments Animals and humans are still essentially different (Bailey, 2008)

41 of 42

Ethics in Animal Research

Animal study can only be done if:

Has a “clear scientific purpose”

Increase scientific knowledge on behaviour
Increase understanding in certain species
Give results that benefit humans or other animals

its use has to be effective

Best species to address research
Minimum amount used
Animals should be treated humanely

All should be submitted to ethics committee before conducted
Researchers should be familiar with its species

If research seems to distress animals, euthanasia should be done
Animals in lab shouldn’t be released into the wild

42 of 42

References

InThinking

Oxford IB Psychology Course Companion