03-psy 101u-lecture 3-the biological perspective on psychology

PSY 101U: Introduction to Psychology

Psy Lecturer: Dr. Afroditi Papaioannou-Spiroulia

E-mail: [email protected]

Lecture 3

Source of basic material:

Dr. A. Papaioannou-Spiroulia

BASIC POINTS:

• Basic issue: Why different approaches/perspectives?

• The Biological Approach

On the Origin of the Species; Darwin, evolution and Psychology

General introduction

Why different approaches/perspectives?

Psychology and Behavior:

Given the richness and complexity of behavior, psychologists have involved different approaches to understand it.

Ideally, we would have one simple set of principle in order to explain every aspect of human being/experience. At present… NO such theory has been developed… or at least which has met with broad acceptance.

In effect, we have many and different approaches on Psychology.

DIFFERENT APPROACHES/PERSPECTIVES ON PSYCHOLOGY

In Psychology, each approach represents a distinct framework for the study of behavior.

Important note! If we understand how these frameworks arose, and how they differ, we can:

better evaluate the significance of each approach

make sense of the field as a whole.

And, this…

is science

means that we become/develop as modern psychologists characterized by critical thinking!

DIFFERENT APPROACHES/PERSPECTIVES ON PSYCHOLOGY

Scientists (e.g. psychologists) formulate theories based on the information they’ve gathered from research.

The development and the evaluation of a theory depends not only or simply on the available data, but also on social and personal factors. This…

supports the idea of how we perceive the world and

the existence of so many perspectives on Psychology, as well.

Contemporary Psychology:Psychology’s 3 main “levels” of analysis

BASIC PERSPECTIVES/APPROACHES:

• BIOLOGICAL APPROACH

• BEHAVIORIST APPROACH

• COGNITIVE APPROACH

• PSYCHODYNAMIC APPROACH

• HUMANISTIC APPROACH

• PERSPECTIVES ON DEVELOPMENT

• PERSPECTIVES ON SOCIAL BEHAVIOR

• PERSPECTIVES ON ABNORMAL BEHAVIOR […]

PERSPECTIVES ON PSYCHOLOGY

HARD CORE OF THE BIOLOGICAL PERSPECTIVE:

• Is based on the assumption of materialism, which asserts that all behavior has a physiological basis.

• The two primary concerns of the biological approach are:

the workings of the nervous system (see neurons)

the role of heredity in behavior (see genes).

• The most challenging question(s) in this field: What’s the relationship between the mind and the brain? Which is the nature of consciousness?

• Focus on the effects of the body on the mind (e.g. the effects of psychoactive drugs, the use of electrical stimulation of the brain, the effects of the split brain).

These are the issues we’ll cover today from/for a biological perspective.

THE BIOLOGICAL APPROACH

GENES

[http://www.google.gr/url?sa=i&source=images&cd=&cad=rja&docid=iXPLF0zib_JgdM&tbnid=JF899ivYC144LM:&ved=&url=http%3A%2F%2Fwww.virtualmedicalcentre.com%2Fhealth-investigation%2Fgenetic-testing-for-hereditary-diseases%2F62&ei=azFhUpmZNImItQbUzIHwBQ&psig=AFQjCNEV37b1oRTOV2iWCFlvdorVHL5Kkg&ust=1382187755905256]

Genes: Our Biological Blueprint – genes

Q: Our genes predispose our biology; does this

mean they determine our behaviors?

‘Nature’ = Genes = Biology = Physiology = DNA…

Genes• biochemical units of heredity that make up the chromosomes• segments of DNA capable of synthesizing a protein• building blocks of our physical and behavioral development.

Genes: Our Biological Blueprint – chromosomes, DNA

Chromosomes

• threadlike structures made of DNA that contain the genes

DNA (deoxyribonucleic acid)• complex molecule containing the genetic information that

makes up the chromosomes• has two strands-forming a “double helix” –

held together by bonds between pairs of nucleotides

Genes: Our Biological Blueprint – genes location and composition

Nucleus Chromosome Gene

Cell DNA

Genes: Our Biological Blueprint – predisposition of our biology

Genes…

- do predispose our biology, by the time they

provide our biological blueprint through

chromosomes-proteins-DNA

- do help to explain our behavior

- don’t determine our behavior

Evolutionary Psychology:scientists, basic principle

Q: How do evolutionary psychologists use natural

selection to explain behavior tendencies?

Evolutionary Psychology• the study of the evolution of behavior and mind, using

the principles of natural selection

Natural selection• the principle that, among the range of inherited trait

variations, those that lead to increased reproduction and survival will most likely be passed on to succeeding generations.

Evolutionary Psychology:mutation and gender

Mutation

• random error in gene replication that leads to a change in the sequence of nucleotides

• the source of all genetic diversity

Gender• the characteristics, whether biologically or socially

influenced, by which people define male and female

Basic study• How natural selection has shaped our universal behavior

tendencies?

Evolutionary Psychology:natural selection as an answer-key

Evolutionary psychologists…

- study how natural selection has shaped our universal behavior tendencies

- support the idea that if organisms vary and if only the most ‘mature’ survive, then nature must select their tendencies

- this could explain gender differences in sexuality

Critics: they make hindsight explanations.

Behavior Genetics: Predicting Individual Differences –

scientists, environment

Q: How do behavioral geneticists explain individual

differences?

‘Nurture’ = Environment = experience = culture…

Behavior Genetics• study of the relative power and limits of genetic and

environmental influences on behavior

Environment• every non-genetic influence, from prenatal nutrition to the

people and things around us.


studies

Behavior Genetics base on studies with: • twins (identical, fraternal)• adoption• temperament (a person’s characteristic emotional activity

and intensity)

Interaction• the effect of one factor (such as ENVIRONMENT) depends on

another factor (such as HEREDITY)• nature-nurture interaction.


studies with twins

Identical twins

• develop from a single fertilized egg, that splits in two, creating two genetically identical organisms

Fraternal twins• develop from separate eggs• genetically no closer than

brothers and sisters, but they share the fetal environment.

Identicaltwins

Fraternaltwins

Samesex only

Same oropposite sex

Behavior Genetics: Predicting Individual Differences

Behavioral geneticists…

- study how genetic and environmental factors influence our development

- based on studies related with twins, adoption and temperament try to identify the extent to which various traits and behaviors are inherited

- based on scientific data about inheritance, support the idea that both nature and nurture influence our developing personality.

Environmental influence:placenta and prenatal nutrition

Two placental arrangements in identical twins

Environmental influence:experience and brain development

Experience affects brain development

Impoverished

environment

Rat brain

cell

Rat brain

cellEnriched

environment

Environmental influence

Q: To what extent are our lives shaped by parental

nurture, prenatal nutrition, early stimulation,

and peer influences?

The entire above factors do shape us, but it’s very hard to determine the exact extent of them to us, by the time, for example, parental nurture matters, but it’s not the sole determinant of who we are or become

- Environmental factors are pervasive as genetic ones

- All of them interact and influence us.

NEURONS

[http://www.google.gr/url?sa=i&source=images&cd=&cad=rja&docid=0o-qkG3fd9djFM&tbnid=zXov3nlxswcp0M:&ved=&url=http%3A%2F%2Fjacgoade.blogspot.com%2F2009%2F10%2Fhippocampal-neuron.html&ei=OjJhUo-FEbTU4QTY7YEw&psig=AFQjCNF4hnGo-Oy3WTkZkO7Yb49VzrQqFw&ust=1382187962323846://www.google.gr/url?sa=i&source=images&cd=&cad=rja&docid=iXPLF0zib_JgdM&tbnid=JF899ivYC144LM:&ved=&url=http%3A%2F%2Fwww.virtualmedicalcentre.com%2Fhealth-investigation%2Fgenetic-testing-for-hereditary-diseases%2F62&ei=azFhUpmZNImItQbUzIHwBQ&psig=AFQjCNEV37b1oRTOV2iWCFlvdorVHL5Kkg&ust=1382187755905256]

Biological Psychology

Biological Psychology

• branch of Psychology concerned with the links between Biology and behavior

• some biological psychologists call themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists.

Q: Why do psychologists study Biology?

A first step in understanding our behavior and mental processes is to examine the biological roots of how we think, we feel, and act in everyday living and practice.

Neurons and Neural Communication:neuron, dendrite

Neuron• a nerve cell• the basic building block of the nervous system.

Dendrite• the bushy, branching extensions of a neuron• receive messages and conduct impulses toward the cell

body.

Neurons and Neural Communication:axon, myelin

Axon• the extension of a neuron, ending in branching terminal fibers,

through which messages are sent to other neurons or to muscles or glands.

Myelin• a layer of fatty tissue segmentally encasing the fibers of many

neurons• enables vastly greater transmission speed of neural impulses as

the impulse hops from node to node.

Neurons and Neural Communication:action potential, threshold

Action Potential

• a neural impulse; a brief electrical charge that travels down an axon• generated by the movement of positively charged atoms in and out of

channels in the axon’s membrane.

Threshold• the level of stimulation required to trigger a neural impulse.

Neural Communication

Neurons and Neural Communication:neurons and information transmitted

Q: What are neurons? How do neurons transmit

information?

Neurons are nerve cells and transmit information:

neuron receives signals through dendrites – combines signals in cell body – threshold – transmits electrochemical impulse down axon –message passes to neurons/muscles/glands.

Neural Communication:synapse

Synapse

• junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

• tiny gap at this junction is called the synaptic gap or cleft.

Neural Communication:neurotransmitters

Neurotransmitters• chemical messengers that traverse the synaptic gaps between

neurons• messages: excitatory or inhibitory• when released by the sending neuron, neurotransmitters travel

across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether the neuron will generate a neural impulse.

Neural Communication:neurotransmitters

Q: How do nerve cells communicate?

An electrical impulse down sending neuron’s axon – electrical signals release neurotransmitters – molecules pass on their messages(excitatory or inhibitory) as they traverse synapse – reach receiving neuron.

Neural Communication:basic neurotransmitters and their functions

Neural Communication:neurotransmitters and influence of human behavior

Endorphins“morphine within” natural, opiate like neurotransmitters linked to pain control and to pleasure.


Q: How do neurotransmitters influence humanbehavior?

Neurotransmitters do influence our behavior. For example, endorphins are neurotransmitters which make us feel good. Based on them, and on other neurotransmitters too, we can understand how drugs affect our brain chemistry. Actually, drugs and other chemicals can alter neurotransmission, by the time them can mimic particular neurotransmitters (‘agonists’), while other can block them (‘antagonists’).


Neuro-

transmitter

molecule

Receiving cell

membrane

Receptor site on

receiving neuron

Agonist mimics

neurotransmitter

Antagonist

blocks

neurotransmitter

Nervous System:major divisions and their functions

Nervous System• the body’s speedy, electrochemical communication system • consists of all the nerve cells of the peripheral and central

nervous systems.

Central Nervous System (CNS)• the brain and spinal cord.

Peripheral Nervous System (PNS)

• the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.

Nervous System:major divisions

CNS

(Central Nervous System)

brain + spinal cord

NERVOUS SYSTEM

Autonomic nervous system

controls self-regulated actions of

internal organs and glands (heart)

Skeletal/somatic nervous system

controls voluntary movements of

skeletal muscles

Sympathetic division

(arousing)

Parasympathetic division

(calming)

PNS

(Peripheral Nervous System)

sensory + motor neurons

Brain:scientific study methods

Scientists have studied our brain through lesioning, CT (computed tomography), EEG (electroencephalography), MEG (magnetoencephalography), PET (positron emission tomography), fMRI(functional magnetic resonance imaging) etc.

Lesion• tissue destruction • a brain lesion is a

naturally or experimentally caused

destruction of brain tissue.


EEG• an amplified recording

of the waves of electrical activity that sweep across the brain’s surface

• these waves are measured by electrodes placed on the scalp.


CT (computed tomography) Scan• a series of x-ray photographs taken from different angles and

combined by computer into a composite representation of a slice through the body; also called CAT scan.

PET (positron emission tomography) Scan• a visual display of brain activity that detects where a radioactive form

of glucose goes while the brain performs a given task.

MRI (magnetic resonance imaging) • a technique that uses magnetic fields and radio waves to produce

computer-generated images that distinguish among different types of soft tissue; allows us to see structures within the brain.

Brain:scientific study methods: PET, MRI

Brain:cerebral cortex: primary functions

fMRI scan shows the visual cortex activated as the subject looks at faces.

Brain:cerebral cortex: primary functions

Brain:cerebral cortex: higher functions

More intelligent animals have increased “uncommitted” or association areas of the cerebral cortex.

Brain organization:specialization and integration

Brain activity when hearing, seeing, and speaking words.

Brain re-organization:plasticity

Q: Is the brain capable of re-organizing itself if

damaged?

Re-organization = Plasticity

Plasticity• the brain’s capacity for modification, as evident in brain re-

organization following damage (especially in children) and in experiments on the effects of experience on brain development

• brain is less plastic as we grow• ‘healthy’ hemisphere helps the ‘damaged’ one• nearby neurons compensate for damaged one (patient with

minor stroke).

Brain re-organization:split or divided brain

Q: What is a split brain? What does a split brain

reveal about brain functioning?

A split brain (εγκέφαλος με διατομή μεσολοβίου) is one whose corpus callosum has been severed.

Corpus callosum (μεσολόβιο ή τυλώδες σώμα)• large band of neural fibers• connects the two brain hemispheres • carries messages between the hemispheres.


Experiments on split brains have refined our knowledge of each hemisphere’s special functions• for most people, LH is the most verbal and RH excels in visual

perception and the recognition of emotion.

Corpus callosum

Studies of mean/typical/healthy people with intact brains confirm that each hemisphere makes unique contributions to theintegrated function of the brain.


Split brain

TOPICS OF INTEREST:

• Based on Lecture 3: Focus on the biological approach on Psychology.

• Next, we’ll focus on the behaviorist approach on Psychology.

PLANNIND Lecture 4

[http://us.123rf.com/450wm/scottff72/scottff721307/scottff72130700020/21191749-the-human-brain-blueprint-illustrating-the-different-area-s-of-the-brain-part-of-a-medical-blueprint.jpg]

ANY QUESTIONS?

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FOR ANY FURTHER QUESTIONS

DON’T HESITATE TO ASK ME IN CLASS

OR CONTACT ME VIA E-MAIL

([email protected])

-Always Cc Student Support, as well ([email protected]).

Once again… ANY QUESTIONS, THOUGHTS, IDEAS…?

mailto:[email protected]

03-psy 101u-lecture 3-the biological perspective on psychology

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