evolutionary explanations of human behaviour objectives assess prior knowledge define evolution...

Evolutionary Explanations of Human Behaviour

Objectives

• Assess prior knowledge• Define Evolution • Define Evolutionary Psychology

What is Evolutionary Psychology?

Read the article on page 3 of your resource pack.

Pick out 5 key points from the article and write them on a post-it!

Evolution

DarwinNatural

Selection

Appear Genetic Adaptive

Mastery Test

How much do you already know?Complete the multi-choice test on

page 2 on paperWork on your own in SILENCE!!!

Go! 2min STOP

Marking the Test

• Swap papers!• Mark the answers

as I read them out• How did you do?• You will complete

this again at the end of the topic – aim to improve!

Extension Tasks

• Complete the definitions and the picture of the model on page 1 of your workbook

• Create a poster about the four parts of Modern Darwinism

Human Reproductive

Behaviour

SexualSelection

Parental Investment

Objectives

• State the nature of sexual selection• Evaluate the nature of sexual selection• State the forms of sexual selection• Evaluate the forms of sexual selection• State the consequences of sexual

selection• Evaluate the consequences of sexual

selection

My ideal partner!

• Take a piece of plain paper.• Draw the head of a person.• Fold it over and pass left.• Draw the body and arms of a person• Fold it over and pass it left• Draw the legs and feet of a person• Fold it over and pass it left

Key Definition!

• EEA (Environment of Evolutionary Adaptation)

• This is the environment to which a species is adapted and the set of selection pressures that operated at this time.

• Generally regarded as the time when our ancestors were hunter-gatherers on the African savannah.

Nature of sexual selection – Gender Specific

• Characteristics to promote reproductive success

• Men – young healthy females• Women – resource investment• Female – more choosy (intersexual

competition)• Male – compete with each other

(intrasexual competition)

Evaluation

• Buss (1989) study of 37 cultures. • Men – choose on fecundity• Women – choose on resource

potential• Scheib (1994) – sperm donor choice

study supported Buss’ findings

Evaluation

• Bereczkei (1997) – females advertised for family-orientated men

• Female financial independence• Homosexual relationships – no

reproductive potential.• Dunbar (1995a) Homosexual adverts

also advertise resources – despite having no reproductive potential

Nature of Sexual SelectionOrigins of Mate Preferences

• Preference for one mate over another

• Links to problem of appropriate mate choice in EEA

• Mating biased in favour of individuals with certain characteristics

• Genetic quality of mate determines genetic quality of offspring!

Evaluation

• Human behaviour influenced by selective pressure in EEA is not universally accepted.

• Continuing evolution• Why so affected by one environment

and not another?

Forms of sexual selection – Selection for Indicators

• Indicators reveal traits that can be passed on.

• Show information about mate survival• Tend to be condition dependent –

healthier = bigger – or revealing – make better use of indicators, e.g. better groomed

• Pre-programming

Evaluation

• Indicators can be faked! E.g. female lips

• Handicaps only reliable indicator (Zahavi 1975)

• Facial symmetry.

Forms of sexual selection Selection for sperm

competition• Sperm is stored• Size matters!• Male humans have medium-sized

testicles by primate standards.• Ancestral males mildly competitive –

females must have had multiple partners (Baker & Bellis 1995)

Evaluation

• Humans are by nature more promiscuous than monogamous

• 9% misattributed fatherhood (Baker & Bellis)

• Majority of people do know who their father is

• Majority not adulterous

Competition Activity

• Complete the human intra-sexual competition activity.

• Be prepared to share your opinions

Consequences of sexual selection

Physical Characteristics• Dimorphism (physical

differences between the sexes) is linked to female mate choice Martin et al. (1994)

• Size difference = polygynous mating system (one male, many females)

• More sexual competition between males.

Consequences of sexual selection

Physical Characteristics• Facial Characteristics• Neotenous (child-like) more

attractive (Perrett et al 1994)• Strong testosterone linked features • Facial symmetry (Thornhill &

Gangstad 1993)

Sexual selection & Human mental evolution

• Physical and mental

• Neophilia (love of novelty)

• Favour the creative (Miller 1998)

Extension Task

• Complete the task on Fisher’s hypothesis.

Human Reproductive

Behaviour

SexualSelection

Parental Investment

Objectives

• State & evaluate parental investment theory

• Compare and contrast the differences between maternal and paternal investment and evaluate these

Fisher’s Hypothesis

• What did we find out?

Key Definition

• Parental Investment – any investment by a parent in one of his or her offspring that increases the chance that the offspring will survive at the expense of the parent’s ability to invest in any other offspring (alive or yet to be born) (Trivers 1972)

Parental Investment Theory

• Trivers (1972)• Males and females do not invest

equally• Gametes

Evaluation

• Plausible explanation (Buss 1998)• Men gain from polygyny. Females

from monogamy.• Polygyny common prior to Western

influence. (Smith 1984)• Reproduction rates are low among

wealthy people.• Contraception• Socially enforced monogamy

Maternal vs. Paternal

EggPregnancyChildbirthFeedingCare

Symons (1979)

Sperm----

Daly & Wilson (1978)

Evaluation

• Females want male providers because of infant dependency

• Female want good quality offspring.• Mistaken paternity supports this.

Cuckoldry

• Self-protection against cuckoldry• Considerable investment = need for

fidelity (Miller 1998)• Care not misdirected

Paternal love

• Read the article on paternal love in the resource pack

• Pick out 5 key points and transfer to post-it notes

• Be prepared to share

Sexual Jealousy

• Different adaptive problems for males and females

• Males – incorrect investment• Females – diversion of resources• Sexual jealousy a solution (Buss 1995)• Men – jealous of sexual act• Women – jealous of shift in emotional

focus

Evaluation

• Buss et al. (1992) male concerned with sexual fidelity, female concerned with emotional fidelity.

• Galvanic skin responses• Veil• Changes in sexual morals• Surplus of men means marital life is

more stable (Hill & Hurtado 1996)

Evaluation

• Dunbar (1995b) Joint parental investment is desirable because of high cost of successful reproduction.

• Males restrict reproductive activity and invest more in each offspring.

• Greater male selectivity means female attractiveness is important compared to non-human animals.

Sexual Jealousy

• Complete the activity on sexual jealousy in the activity pack.

• Be prepared to share your answers

Extension Activity

• Complete the activity on polygyny and polyandry

• Ensure it is complete by next lesson.

Human Reproductive

Behaviour

SexualSelection

Parental Investment

Objectives

• State the main ideas about parent-offspring conflict

• Evaluate the main ideas about parent-offspring conflict

Polygyny & Polyandry

• What did we find out?

Parent-offspring conflict

• Trivers (1994)• Parents will be in conflict about

weaning, parents will want to wean earlier than the child

• Parents will encourage children to value siblings more than they are naturally inclined to

• Parents will punish conflict and reward co-operation.

Sibling Rivalry

• Individual offspring• Fair share• Maximise fitness• Sibling rivalry for

attention and resources

Evaluation

• Lalumiere et al. (1996) Different developmental paths

• Harris (1999) Peer socialisation

Age related parent-offspring conflict

• Begins at conception (Buss 1999)

• Pre-eclampsia• Sibling investment• Transfer of

investment

Evaluation

• High blood pressure beneficial (Xiong 2000)

• Alliances against non-kin

• Learned negotiation skills (Shaffer 1993) – a non-evolutionary explanation

Parent-offspring conflict activity

• Read the article on parent-offspring conflict

• Pick out 5 key points ready to share....

Extension Activity

• Complete the cut ‘n’ stick for the first section of the topic

• Ensure it is complete by next lesson

Human Reproductive

Behaviour

SexualSelection

Parental Investment

Objectives

• Review what we have learned so far

• Construct an answer to an essay that meets/exceeds ALIS target

Mastery Test

How much do you now know!?Complete the multi-choice test on


Go! 2min STOP

Marking the Test


as I read them out• How did you do?• Did you improve?

AO1 & AO2

• Lets look at what makes effective A01 and AO2

• Lets review some essay plans

Writing an Essay

• Choose one of the essay titles

• Try to choose whichever you think is most challenging to you.

• Review the section of work

• Write for 30 mins

Reviewing our Essays

• Swap with someone near to you• Read their work• Write one thing that is good• Write one thing they could improve

on• Give a mark and explain why you

have given this

Objectives



Mental Disorders

UnipolarDisorder

BipolarDisorder

Depression

Anxiety

Phobias OCD

Objectives

• State the symptoms of depression• State the differences between

unipolar and bipolar disorder• State the evolutionary explanations

of unipolar disorder• Evaluate the evolutionary

explanations of unipolar disorder

Mastery Test



Go! 2min STOP

Marking the Test




Depression is:

• Using mini-whiteboards in groups of 3:

• Create a mind map of symptoms of depression.

• You have 5 minutes!• Be ready to share your answers!

Unipolar and Bipolar Disorder

• Unipolar

• Consists of depressive phase only

• Bipolar

• Consists of manic and depressive phases and shift between the two

Evolutionary Explanations of

Depression

UnipolarDisorder

Social CompetitionHypothesis

DefectionHypothesis

BipolarDisorder

ReproductiveFitness

EOBDHypothesis

Social Competition Hypothesis

• Price et al (1994)• Depression is an evolved response to

loss of status• An adaptive response to losing rank

and seeing self as a ‘loser’• Prevents risk of further injury• Preserves relative stability of social

group• Prevents further competition

Evaluation of social competition hypothesis

• Difficult to test• Gilbert & Allan (1998) found feelings

of defeat were significantly correlated with depression

• Rank Theory (Price & Sioman 1987)• Yielding subroutine• Winning subroutine


Depression

UnipolarDisorder


DefectionHypothesis

BipolarDisorder

ReproductiveFitness

EOBDHypothesis

The defection hypothesis

• Hagen (1999)• Post-natal depression an adaptive

response – led women to limit investment in the child as this would reduce overall reproductive success.

• Hagen (2002)• Can be generalised to all forms of

depression because it is a response to an event that has an evolutionary significant cost

Evaluation of defection hypothesis

• Considerable empirical support• Lack of social support predicts this

(Gotlib et al. 1991)• Poor environment predicts this

(Warner et al. 1996)• Post-natal depression results in loss of

interest in child (Beck 1992)• Post-natal depression leads to

increased paternal investment (Hagen 2002)

Extension Task

• Complete the case study 1 activity on your whiteboard.

Case Study 1

• Lets share our answers!

Homework

• Log onto www.ashlawnpsych.wordpress.com

• Follow the instructions under the post Year 13 Evolutionary Homework due 9th October

http://www.ashlawnpsych.wordpress.com/

Objectives



of unipolar disorder• Evaluate the evolutionary

explanations of unipolar disorder


Depression

UnipolarDisorder


DefectionHypothesis

BipolarDisorder

ReproductiveFitness

EOBDHypothesis

Objectives



of bipolar disorder• Evaluate the evolutionary

explanations of bipolar disorder

Homework

• Log onto www.ashlawnpsych.wordpress.com

• Follow the instructions under the post Year 13 Evolutionary Homework due 9th October

http://www.ashlawnpsych.wordpress.com/

Reproductive fitness

• Beneficial genes are passed on• Possession of bipolar genes an

advantage• Small doses v large doses – normal

distribution curve

Evaluation

• Based on assumptions – caused by multiple genes and the genes are linked to desirable behaviour

• Lack of genetic evidence – chromosome 22 (Kelsoe et al. 2001)

• Twin studies – high concordance (Nesse 1999)

• Number of genes involved• Expression of gene may be modified


Depression

UnipolarDisorder


DefectionHypothesis

BipolarDisorder

ReproductiveFitness

EOBDHypothesis

EOBD Hypothesis

• Sherman (2001) ‘bipolar behaviours are adaptations to the selective pressures of long severe winters and short summers.’

Evidence for EOBD:

• Cold-adapted physique:

• Bipolar linked to thick compact physique

• Large trunk, small extremities• Improved clothing and shelter made

this adaptation unnecessary• (Kretschmer 1970)

Evidence for EOBD

• Hibernation:

• Bipolar evolved in response to environmental adversity

• Depressive phase resembles hibernating behaviour

• For example – overeating then lethargy and depression similar to animals gorging and then sleeping. (Sherman 2001)

Evidence for EOBD

• Adaptive significance in social groups• Inactivity in winter preserves

harmony and survival• High energy requirement• Mania link to challenge, survival and

emergencies • Aiello & Wheeler • (1995)

Evaluation of EOBD

• Previc (2002) Hypothesis is unproven• Makes intuitive sense• Tries to explain original development

not cause• Arbisi et al. (1994)• Neurophysical support – dopamine

fluctuates seasonally

Case study 2

• Read case study 2• Complete the

questions on paper• Be ready to share

your answers!

Extension Task

• Complete the comparison flow chart between unipolar and bipolar disorder

Flowcharts

• Lets share our answers!

Objectives



of bipolar disorder• Evaluate the evolutionary

explanations of bipolar disorder

Mental Disorders

UnipolarDisorder

BipolarDisorder

Depression

Anxiety

Phobias OCD

Objectives

• State the symptoms of anxiety• State some types of anxiety

disorders

Anxiety is:

• Using big paper and pens in groups of 3:

• Create a mind map of symptoms of anxiety.

• You have 5 minutes!• Be ready to share your answers!

Anxiety

• Anxiety can be defined as feelings of apprehensiveness or dread in response to threats that are real or imagined

Symptoms of anxiety

• Fight/Flight/Freeze

The nature of anxiety

• General vs. Specific (Janzen 1981)

• General threat = general response

• Specific threat = Specific response

Anxiety as protection

• Four responses: (Marks 1987)

• Escape or avoidance

• Aggressive defence• Freezing/

immobility• Submission or

Appeasement

Types of anxiety disorder

• Phobias• OCD• PTSD

• You could be asked to explain two of these from an evolutionary perspective

Subtypes

• Subtypes of anxiety have evolved to defend against threat.

• Fear – linked to survival but excessive fear can cause problems such as phobias and OCD

Threat situations and fear response (Mark & Nesse 1994)

• Heights – Induce freezing so unlikely to fall, excess – fear of small heights e.g. stairs

• Public places – guards against danger away from home territory, excess – agoraphobia

• Post-traumatic fear – Avoidance of repeated trauma, excess – PTSD

• Social threats – minimize threat of group rejection, excess – dysmorphophobia & OCD

Obsessive-Compulsive Behaviour

• Exaggeration of mechanisms that drive adaptive behaviour

• Grooming behaviour – reduces parasitism in mammals -> excess washing

• Concern for others – ensures group stability -> fear of harming others

• Hoarding – guards against shortages -> hoarding of all things

Is anxiety adaptive?

• Without it you would die! (Tyrell & Baxter 1981)

• Adrenal gland removal = death• Pleasurable fear – films, roller-

coasters• Learning

• Why might anxiety be maladaptive?

Are anxiety disorders inherited?

• Kendler et al. (2000) 3000 twin studies – common genetic factor in all phobias and unique genetic factor for specific ones.

• Nestadt et al. (2000) People with a first-degree relative with OCD 5x more likely to have OCD in their lives than those without.

Anxiety

Adaptive Maladaptive

Extension Task 1

• Read the anxiety article in the resource pack

• Pick out five key points

Extension Task 2

• Find an example of a story about fear in the media and bring to next lesson

• Make a list of treatments for anxiety disorders and the main components (at least 3)

Objectives

• State the symptoms of anxiety• State some types of anxiety

disorders

Mental Disorders

UnipolarDisorder

BipolarDisorder

Depression

Anxiety

Phobias OCD

Objectives

• State types of anxiety disorder• State and evaluate Pre-potency• State and evaluate Preparedness

Phobias Extension Task

• What were your key points?

Evolution of Anxiety Disorders

• Ancient fears• Snakes, heights, storms, darkness,

strangers, seperation• Phobias – exaggeration of these fears• Other stimuli eg, leaves no threat = no

phobia• Modern dangers eg cars rarely form

phobias because these have not been around long enough to have influenced adaptive selection.

Pre-potency

• Evolved to respond to potential threat (little point in experiencing anxiety after a loss!)

• Ancestors able to respond to threats more likely to survive and more likely to pass on genes.

• Natural selection shaped nervous system to respond to cues

• E.g. noise and visual stimuli of a snake-like object may cause big anxiety response

• This is PRE-POTENCY – where something has power to direct experience.

Evaluation ofPre-potency

• Ohman & Soars (1994)

• Masked pictures – bigger anxiety response than neutral pictures

Evaluation ofPre-potency

• Bennet-Levy & Marteau (1984)• Form and texture different to human

= greatest fear.• 1 exception – slugs!

Preparedness

• Learning rather than fixed response• Seligman (1970) – learn an

association between stimuli and fear, once learned, difficult to extinguish, passed on genetically.

• Fear in infants gauged by mother’s reaction. (Marks 1987)

Evaluation

• Strangeness is the problem not the stimulus itself.

• Prepared to fear the strange – learn not to.

• Explains high rate of phobias in childhood and adolescence and reduction in adulthood.

Evaluation

• We learn some fears readily and these are difficult to unlearn. McNally (1987)

• Expectancy bias – fear relevant stimulus (danger, unpleasantness) produces future responses. No need to invoke evolutionary history.

• Modern phobias unexplained (eg. Hypodermic needles)

Nausea and Alcohol

• Garcia & Koelling (1966) rats & saccharin

• Berstein (1978) Ice-cream & Chemotherapy

• Why do people persist in drinking alcohol when it makes them feel sick?

Little Albert

• Complete the activity on Little Albert from your resource pack

• Be ready to share your answers!

Extension Task 1

• Complete the Evolutionary explanations of mental disorders task.

Extension Task 2

• Mind map an essay title for depression and for anxiety

• Choose the one you are then least comfortable with and write it!

Objectives

• State types of anxiety disorder• State and evaluate Pre-potency• State and evaluate Preparedness

Mental Disorders

UnipolarDisorder

BipolarDisorder

Depression

Anxiety

Phobias OCD

Objectives



Mastery Test



Go! 2min STOP

Marking the Test



AO1 & AO2



Writing an Essay








have given this

Objectives



Development of Human Intelligence

Foraging

SocialTheories

Language

Brain Size

Objectives

• State and evaluate evolutionary factors in the development of human intelligence including:

• Foraging demands• Social demands• Language

Mastery Test



Go! 2min STOP

Marking the Test




Intelligence is:

• Using big paper and pens mind map in pairs what you think intelligence is

• Include anything you think is associated with intelligence

• Be ready to share!

Some key definitions:

• Intelligence – the ability to think flexibly

• Primates – includes lemurs, monkeys and apes

• Great apes – the most advanced group of primates including gorillas, chimpanzees and humans

• Hominids – early humans

Why did intelligence evolve?

• Survival• Food• Shelter• Mating

Foraging – Finding food

• Dunbar (1992)• Fruit-eaters had high cognitive demand• Needed to monitor food supply and

ripening patterns, develop harvesting plans and survive in the interim

• Leaf-eaters had lower cognitive demand as food more readily available

• Hominids were fruit eaters

Foraging – tool use

• Mercader et al. (2002)• Chimps use stones as hammers to

crack open nuts• Most successful hunter-gatherers

also used tools• These tribes survived

Evaluation of foraging

• Is tool use a cause or an effect of intelligence?

• Is tool use developed by trial and error learning?

• Visalberghi & Trinca (1987) – Monkeys used trial and error to find suitable tools and showed no understanding of why one worked and not another

• Byrne (1995) only chimps use tools in the wild

Social Theories

• Machiavellian Intelligence (Whiten & Byrne (1998) – Human intelligence may be an adaptation to social problem solving. Individuals able to use others without causing aggression would be favoured. This deceit seems cooperative but is actually selfish

Evaluation

• Dunbar (1992)• Strong positive correlation between

group size and neocortex ratio• Polygamous primates had a larger

neocortex ratio than monogamous ones – polygamy involves more complex social relations

Machiavellian Intelligence

• Forming alliances• Harcourt (1992)• Power in social groups = right allies

not physical strength• Alliances formed based on ability to

provide useful future help

Machiavellian Intelligence

• Manipulation & deception• Byrne (1995)• Manipulate others into providing

unwitting help• Ability to understand and plan

deception• Diversions of attention

Evaluation

• Byrne & Whiten (1992)• Strong positive correlation between

amount of tactical deception and neocortex ratio

• Suggests a clear relationship between social manipulation and intelligence

Evaluation

• Cosmides (1989)• Variations of the Wason card task• Particpants solved it 75% of the time

if it is a social context• Only solved 21% of the time with

unfamiliar context• Suggests a link between intelligence

and social problems

D F 73If a card has a ‘D’ on one side it has a ‘3’ on the other side.

Which cards do you need to turn over to find out if this is true?

Beer Coke 25 16

You are a bouncer in a bar.

You must make sure that no under-age drinkers have beer.

Each card is a customer

It says age on one side and drink on the other

Which cards need turning over?

Meat-sharing Hypothesis

• For ancestors in the EEA meat was an important source of saturated fat

• Chimpanzees face similar problems today

• When they do manage to kill they eat the fattiest parts first not the lean tender flesh

Meat - sharing

• Meat could be used to form alliances• Meat could be used to persuade females

to mate• Stanford (1992) observed:• Males withheld meat until after sex• Hunting more prevalent when females

were sexually receptive• Sexually receptive females had more

success when begging for meat• Requires individual recognition and scores

of debts, credits and relationships

Evaluation

• Hill & Kaplan (1988)• Men in Paraguay give women meat

for sex• Gilby (2001) males share meat with

receptive and non-receptive females• Mitani and Watts (2001) males share

meat with other males to form alliances because hunting was more successful in groups

Language

• Humans are the only species to develop this spontaneously.

• Other species show precursors – attributing intentions and beliefs to others (eg. Sally-Anne test)

• Chimpanzees and gorillas express thoughts and emotions through sign language and understand human communication

Evaluation

• Human language is likely to be the outcome of rather than the cause of intelligence

• Once language evolved it had a significant effect on further intelligence development

• Cultural transmission is only possible through language

• Vygotsky – language transforms elementary mental functions (possessed by all animals) into higher mental functions

Human Intelligence

• Read the article on human intelligence in the resource pack

• Pick out 5 key points and write them on post-it notes.

• Be ready to share!

True or False?

• Complete the activity True/False questions of intelligence using what we learned today.

• How will you do?

Extension Activity

• Using Activity 8 on Cosmides and Tooby’s study, conduct the experiment and bring your results to next lesson

Objectives

• State and evaluate evolutionary factors in the development of human intelligence including:

• Foraging demands• Social demands• Language


Foraging

SocialTheories

Language

Brain Size

Objectives

• State and evaluate theories into the relationship between brain size and intelligence including:

• Comparative studies• Human Studies

Cosmides & Tooby

• What were the results of your study?

Brain Facts

• 2% of body mass – 20 % of metabolic rate

• Large brains would not have evolved unless they gave humans a significant advantage

• Important in cognitive development

Comparative studies

Brain Quantity

• Absolute brain size – Most intelligent species would be the ones with the biggest brains = sperm whale

• Big brain = big body• Need to control and maintain big

body needs a big brain

Brain quantity

• Brain:body ratio• Jerison (1978)• Encephalization quotient (EQ)• Actual brain mass is divided by

expected species brain size• High EQ = High intelligence• Humans = 7 (highest), other

primates 2.34, Dolphins = 4.5

Evaluation

• EQ not supported by research• Macphail (1982) rats and squirrels

had the same performance on a learning task but rat EQ = 0.40 squirrels EQ = 1.10

• Different species comparison is difficult.

• Different perceptual systems

Brain Quality

• Holloway (1979)• Growth of the

neocortex is responsible for evolution of intelligence

• Mammals 6 layers of neocortex

• Cetaceans (whales, dolphins) 5 layers.

Evaluation

• Cetacaens are highly intelligent• Herman (1986) – Dolphins can

understand human language and perform complex tasks beyond the ability of chimpanzees.

• Fewer neocortical layers but the same neural density and size of frontal lobes as humans

Brain size in Humans

Head size and IQ

• Sir Francis Galton (1888)• Studied Cambridge undergraduates• Insignificant relationship between head

size and intelligence• Wickett et al. (1994) repeated and found

significant relationship• Broman et al. (1987) Head perimeter at

birth predicted head perimeter at age 7 and head perimeter at both ages predicted IQ

MRI measures

• A recent development which allows accurate measurement of brain size

• Andreasen et al. (1993) found significant relationship

• Tan et al. (1999) used male and female Turkish students and found a significant relationship.

Evaluation

• Other meaningless correlations also found, eg. Amount of cerebrospinal fluid and IQ (Egan et al. 1994)

• Other causal factors of big brains! • Diet• Some aspects of intelligence not measure by

IQ tests so may be normal in terms of IQ. E.g. expertise is critical to survival and requires brain capacity but not measured by IQ tests

• No simple relationship between brain size and IQ

Brain Structure in humans

Cortical Neurones

• Haug et al. (1987)• Correlation

between brain size and number of cortical neurones

nerve impulses

axon

cell bodydendritesmuscles fibres

motor end plates

Evaluation

• Relationship between neurones and brain size is supported by animals reared in enriched environments have more neurones

• Diamond (1991) – rats reared in enriched environments had larger brains and more neural connections.

• Brain development relies on experience

Grey matter

• Size of the regions of the brain associated with intelligence is under tight genetic control

• Thompson et al. (2001) MRI twin study

• Volume of grey matter is highly heritable and an important determinant of IQ

Evaluation

• Development of grey matter is affected by genes and environment

• Young adults have more grey matter than middle-aged people – likely to be due to improved diet (Storfer 2001)

Sex differences

• Ankey (1992)• Brains of men larger than brains of

women in both European-American and African-American cultures

• Supported by similar studies by Rushton (1992) & Pakkenberg & Gundersen (1997)

Evaluation

• Size differences are accurate• Research cannot account for men

and women obtaining the same IQ scores (Peters 1993)

• Ankey (1992) different intellectual abilities

• Female brains may be better organised (Johnson 1996) as women have larger corpus callosum.

The intelligence gene

• Read the article in the resource pack• Pick out 5 key points and write them

on post-it notes• Be ready to share

That’s all folks!

• That is all the input on Evolutionary Psychology

• Complete the quiz at the end of your resource pack using your knowledge of the whole topic!

Objectives

• State and evaluate theories into the relationship between brain size and intelligence including:

• Comparative studies• Human Studies


Foraging

SocialTheories

Language

Brain Size

Objectives



Mastery Test



Go! 2min STOP

Marking the Test



AO1 & AO2



Writing an Essay








have given this

Objectives



evolutionary explanations of human behaviour objectives assess prior knowledge define evolution...

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