Evolution and
Intelligence
PSYCHOLOGY
What is evolutionary psychology?
oIt focuses on how human beings came to be who we are today
oTooby and Cosmides (1992) define evolutionary psychology as
informed by the fact that the inherited structure of the human mind
is the product of evolutionary processes (!)
oThey claim this can explain contemporary behaviour.
oIt seeks a FUNCTIONAL EXPLANATION of human behaviour – one
that focuses on origins e.g. why a behaviour has evolved.
The Elements of Evolution – Genetic
Transmission and Diversity
oGenetic Transmission and Diversity
oNatural Selection
oSexual selection
DNA
oWhen life first appeared on earth, the structure of DNA was pretty
common to all life forms.
oOver long periods of time, DNA underwent subtle changes and
different species emerged.
oThe shorter the time lapse since one species has split in two, the
closer in structure their DNA will be.
oSince the structure of DNA evolves at a consistent rate, we can work
out mathematically when two species diverged.
But what about God?
As Richard Dawkins,states–
“natural selection is the blind watchmaker, blind because it
does not see ahead, does not plan consequences, has no
purpose in view. Yet the living results of natural selection
overwhelmingly impress us with the appearance of design
as if by a master watchmaker, impress us with the illusion of
design and planning”
(Dawkins, 1986, The Blind Watchmaker
Other ideas
Creationism suggests that we are all made by a god.
Evolution does not exist, regardless of the evidence. Any evidence
that does exist is merely there to show God.
Humans are made in God’s image.
Adam and Eve were the first humans and we are all their
descendants
The evolutionary origins of the human
mind
oWhy are we so evolved? We have complex technology, social lives,
languages and complex cultures. Why do only humans have this?
oMan as Tool Maker was proposed by Oakley in 1949. He said when
our hands were free to make tools when we first walked upright, we
changed the way we thought.
oJane Goodall (1971) found that chimps in the Gombe Stream area of
Tanzania also use tools and make them but they have not developed
human complexity.
Evolution of the human brain
Around 300 million years ago reptiles evolved on earth
Mammals and humans followed much later
Structure of human brain bears witness to this history
There are arguably 3 interconnecting ‘brains’ which each have particular functions:The human brain consists of:
- Reptilian brain
- Mammalian brain
- Neocortex [higher human brain]
Each part has different functions & represent what was important to each species
Reptilian brain
Functions based on survival
Deepest, most ancient part, largely unchanged by evolution
We share this part with all vertebrates
Activates instinctive behaviour related to survival and controls essential bodily functions required for
sustaining life:◦
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Hunger, digestion/elimination
Breathing, circulation, temperature
Movement, posture and balance, territorial instincts
Fight and flight
Mammilian brain
Social behaviour e.g. care & nurturance, playfulness, bonding
Almost the same chemical systems & structure as other mammals, e.g. chimps
Triggers strong emotions that need to be managed well be the rational brain
Also helps to control primitive fight or flight impulses
This part of the brain activates:◦
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Rage, fear, separation distress
Caring and nurturing, social bonding
Playfulness
Explorative urge
Lust in adults
Higher brain
Frontal lobes are much larger allowing us to think more deeply than other animals - A chimp has small frontal lobes so it
thinks mainly in the present
Human = frontal lobes are associated with higher level thinking and allow us to:◦ imagine & be creative
◦ reason & reflect
◦ solve problems
◦ be self aware, show kindness, empathy and concern
◦ to some extent helps us with aspects of speech
◦ also contains the motor cortex – this controls voluntary movement
Newest part of the brain [frontal lobes or cortex] amounts to 85% of total brain mass
Each brain is connected to the other via a massive network of nerves
How the brain grew
oHominids (earliest human relative) had brain more than half the size of ours
oHomoerectus: the brain was still small in 1st upright man 1.5 mill years ago
oHomosapiens: 200,000 years ago brain grew
Humans began painting, making jewellery & ornaments,
adopting religion but it still took a long time for humans to
develop the capacity for sophisticated thinking we enjoy today
Jerison (1973)
Encephalization quotient
Brain size is plotted against body size
- Above line = relatively larger brain than expected
-On line = average brain size
-Below line = relatively smaller brain
Brain size is taken to infer intelligence
‘Encephalization quotient’= actual size of mammals brain divided by that expected for a typical
mammal of its body size
Intelligence
oHow do we measure intelligence today?
oIs it reliable or valid?
oNo agreed definition of intelligence therefore can be difficult to
measure
Goff (2000)
oSuggests that intelligence is “the ability to devise flexible
solutions to problems, which includes learning, learning in
new situations and thinking, reasoning and planning”
The Machiavellian Hypothesis
Taken from Niccolo Machiavelli (1469-1527)
He suggested primates use a mix of cunning and deceit in order to
maintain their place in a social group.
Higher level intelligence
oRichard Byrne and Andrew Whiten (1988) proposed the idea that
the evolutionary origins of high-level intelligence lie in the adaptive
value for social animals of ‘social manipulation, deceit and cunning
cooperation
Higher level intelligence
oTheorised by Humphrey (1976) as being creative and able to infer in novel
situations that something is likely to happen because it is implied by a particular
combination of events.
o
e.g. Man, walking reading a newspaper, hole in ground. What will the
man do?
Higher levels of intelligence and social
worlds
oIt is useful for living in a social group
oCan use to preserve group and outmanoeuvre individual
competitors
oCan help therefore to compete and co-operate.
oHence why it is Machiavellian – the ablility to negotiate what is of
best advantage to you at the least cost, while the individual you are
interacting with is making exactly the same calculation!
Other perks of being social
oThe more social we are, the more we imitate.
oWhen imitating, we are mimicking things not always happening at the same
time.
oThis can lead to planning and thinking about things that aren’t always
happening ‘now’.
oThis means we develop the ability to think abstractly and to simulate possible
actions and outcomes.
oThe abilities to plan, memorise and solve problems are cognitive skills that have
developed and evolved.
oExamples include hunting – imitate, plan, decide how to improve, memorise
this, try it out!
Primitive man in the in the PTE – Pre-Tesco Era
Evolving a Modular Mind
The notion that the human mind is constituted in part by a set of usually
diffused modules that serve specific cognitive-emotional functions.
A little like a swiss-army knife mind!
In hunter-gatherers this may have started with social contracts e.g. ‘I give you
mammoth, you give berries’, then as money was discovered, a new module for
financial transactions would be ‘added’ and so on. As further developments
happened, we now have ‘modules’ for stock exchanges, futures and greedy
bankers!
Example of a Social Contract Model
A social contract model may include
◦ The ability to recognise different individuals
◦ A long-term memory of past exchanges with other individuals in
order to know when to co-operate and when not
◦ Knowledge about what constitutes a benefit and a cost to oneself
◦ Emotional reactions such as anger that signal to others that one
will pursue cheaters
oEvolutionary psychologists argue that the development of modules
in our minds, which allowed us successfully to solve problems in our
ancestral environment, underpins our thinking, feelings and
behaviour today.
Evolutionary Understanding of Social
Behaviour
oThe human ability to mind-read depends on abilities to both
interpret and express emotional states.
oThere is evidence that much emotional expression in humans is
universal.
oCross-cultural psychologist Paul Ekman found people from a variety
of cultures could recognise fear, disgust, happiness, sadness, anger
and surprise.
oEven children born blind and deaf will smile and cry with the same
facial expressions as ‘non-disabled’ children
Altruism and Reciprocity
Dawkins in his book The Selfish Gene suggests that evolution may be
only in terms of being successful for populations not individuals.
We are related to large numbers of people genetically so promoting
the welfare of all those related to us would be a useful reproductive
strategy.
Mutual help would mean that although we helped others, they
would help in our need.
This ‘reciprocal altruism’ explains the evolution of behaviour
benefitting others who are not kin in terms of the adaptive value for
our ancestors of mutual help when they needed it!
Using Evolutionary Psychology
Methods include observation,
hypothetico-deductive reasoning and testing,
reverse-engineering (aka Functional Analysis ) this is the application of the laws of operant
conditioning to establish the relationship between stimuli and responses.
and logical inference supported by evidence.
Contributions to psychology include understanding of behaviour, why behaviours may occur, by
asking functional questions new investigations can be designed
Criticisms include the fact it is deterministic – we have no free will, it’s all in our genes and the
impact of change in the ways we live – we have different lives from the old hunter-gatherers and
this may cause changes to happen quicker.
To conclude
oWe’re a young species descended from monkeys!
oEvolution changed us through adoption of adaptive behaviour.
oThis behaviour helped humans survive and develop.
oIt is suggested that we have evolved different skills and intelligence.
oWe can look at evolution to figure out some of our behaviour today.
oWe can look for functional explanations for why we do what we do,
especially when it is not so healthy for us!
Thank you see you next week!