Transcript Evolutionary Approach

The Evolutionary
Approach to
Psychology
So how did we get here?
HUMAN EVOLUTION
Human Evolution
Carl Sagan’s Universe Calendar
“Big Bang”
Milky Way
Solar System
Life on Earth
Humanlike Primates
January 1
May 1
September 9
September 25
December 31, 10:30pm
Human Evolution
Homo erectus
Scale: Millions of Years BP
Homo habilis
Australopithecus
Human Evolution
Homo habilis
Finds in east Africa indicate that
Homo habilis was not very
different from Australopithecus
the in terms of body size and
shape
612 cc brain
first toolmaker
Projecting jaw, brow ridge
probable meat-eater
possibly arboreal
no speech
Human Evolution
Homo erectus
The earliest Homo erectus
remains indicate rapid biological
change:
H. erectus was considerably
taller than H. habilis.
994 cc brain size (compared to
612 for H. habilis)
Photograph of Nariokotome boy, an
early Homo erectus found near Lake
Turkana, Kenya.
Human Evolution
Homo erectus, Australopithecus & Homo sapiens
Hominid Brains
Human Evolution
Homo erectus
Why was H. erectus so successful?
Less hair on body
Wearing of furs = ability to live further
north
Quick adaptation to environment
without physical changes
Culture
Organisation for hunting
Ability to protect against predators
Control of fire
Used stone tools e.g. hand axes
Human Evolution
Homo neanderthalensis
Discovered in the Neander
Valley near Dusseldorf,
1856
Massive brain--about 1,400cc
on average
Large torso, short limbs,
broad nasal passages
Later remains show decrease
in robustness of the front
teeth and face, suggesting
use of tools replaced teeth
The skull of the classic Neandertal
found in 1908 at La Chapelle-auxSaints.
Human Evolution
Neandertal Culture
Homesites – In caves, also in the
open (near rivers, framed with
wood and covered with skins)
Burial – Is there evidence of
purposeful burial and ritual?
Language – Could Neandertals
talk or not?
Tools – Mousterian tradition
Top: Reconstruction of Neandertal burial from Shanidar cave
Bottom: Mousterian tools
Human Evolution
What happened to Neandertals?
H. neanderthalensis coexisted with H. sapiens for at
least 20,000 years, perhaps as long as 60,000 years
What happened?
Neandertals interbred with H. sapiens
Neandertals were killed off by H. sapiens
H. sapiens drove Neandertals into extinction by
competition
Human Evolution
Homo sapiens
Archaic – 100,000 to
35,000 years BP
Sometimes called Homo
sapiens and Homo
sapiens neanderthalensis
Modern – 35,000 years
BP to present
Anatomically modern
Sometimes called Homo
sapiens sapiens
Human Evolution
H. sapiens Culture
Shelters
Some made with mammoth bones
Wood, leather working; carpentry
Tools
From cores to blades
Composite tools
Bow and arrow
Domestication of dogs
Gathering rather than hunting
became the mainstay of human
economies.
Straw Hut
Mammoth bone hut
Hand tools
Human Evolution
H. sapiens Culture
Traces of art found in beads,
carvings, and paintings
Female figurines
27,000 to 22,000 years
B.P.
Called ‘Venuses’ these
figurines depicted women
with large breasts and
broad hips
Cave paintings from 20,000 years
ago from Lascaux, in southwest
France
Cave paintings
Mostly animals on bare walls
Subjects were animals favoured for their
meat and skins
Human figures were rarely drawn due to
taboos and fears that it would somehow
harm others
Approaches in Psychology
THE
EVOLUTIONARY APPROACH
The Evolutionary Approach
Evolutionary
psychology is an
approach to
psychology
Knowledge and
principles from
theories of
evolution are
applied to research
on the structure of
the human mind
It is not an area of study, like
‘memory’ or ‘social behaviour’.
It is a way of thinking about
psychology that can be
applied to any topic within it.
The Evolutionary Approach
Darwin’s Theory of Evolution
Natural selection
“Natural selection is the gradual
process by which nature selects the
forms most fit to survive and
reproduce in a given environment.”
Charles Darwin
The Evolutionary Approach
Reproduction ensures the continuation of genes
responsible for fitness.
It is the characteristic rather than the
individual that is selected by nature.
Natural selection occurs when:
A characteristic appears
The characteristic is genetically transmitted
The gene is adaptive
The Evolutionary Approach
Sexual Selection
The selection of characteristics that are concerned
only with reproductive success
Females are the selectors whilst males compete
for her attention.
Males produce thousands of sperm and invest
little in each ‘reproduction’
Females invest a great deal as they produce
fewer eggs
Therefore females select their mates strategically!!
The Evolutionary Approach
Evolutionary psychologists explain human behaviour in terms of
ultimate rather than proximate causes.
Proximate explanations emphasise here-and-now
influences on a person’s behaviour
Ultimate explanations focus on how these behaviours
may have been adaptive in a species’ evolutionary past.
The Environment of Evolutionary Adaptation (EEA)
This is the environment to which a species is adapted and the
set of selective pressures that operated at this time
In terms of human evolution, this is generally accepted as
35000 to 3 million years ago when our ancestors lived in
mobile hunter-gatherer groups on the African savannah
The Evolutionary Approach
The Modular Mind
The modern mind
comprises specific mental
modules (hard-wiring in
the brain) that would
have evolved in response
to the specific problems
faced by our ancestors in
the EEA.
Our ancestors are our
ancestors precisely
because they adapted
successfully to these
problems and passed the
same mental modules on
to their descendants (us).
The Evolutionary Approach
The Selfish Gene
Why do animals act altruistically when it would appear ‘sensible’ in
terms of survival, not to risk their life for another?
Inclusive fitness.
Animals pass on copies of their genes not only directly (i.e. through
their own offspring) but also indirectly (i.e. by giving aid to other
genetic relatives).
The total number of genes passed on directly and indirectly adds up to an individual’s
inclusive fitness.
Kin Selection
The tendency to help those with whom we share genes (our gene pool)
is known as kin selection.
As we share 50% of our genes with our children and siblings, 25% with our
grandchildren and nephews/nieces and just 12.5% with our cousins, kin selection
should explain the likelihood of help being given to each ‘level’ of genetic relative.
The Evolutionary Approach
A non-conscious process
No one stopped and said, “How can I
maximize the number of genes I pass
along to the next generation?”
Our past and present natural yearnings
simply reflect the genes’ way of making
more genes.
The Evolutionary Approach
 Increases our knowledge of
Nature-Nurture with
discussions on genes and
how they are vulnerable to
environmental changes.
(X) Evolutionary reductionism –
assumes that behaviour
must have at some time
must have been adaptive
and therefore inherited
(X) Ignores cultural
transmission of behaviour