Week 2 – Human Evolution:
•Attachment system – one hypothesized evolved psychological adaptation that
connects infants to caregivers and later on adults to their romantic partners.
•Rank System: The idea that there is an evolved psychological apparatus to deal
with social hierarchy
•Traces itself to the work of Charles Darwin.
•Born in 1809 in England.
•Degree in 1831 – age 22.
•1st job was w/o pay – as a naturalist on the HMS Beetle – mapping the west and
east coast of South America.
•Groundwork for evolutionary theory was laid down b/w the ages of 23-27.
•Year 1859 - Age 50 when origin of species is published.
•Year 1871 – Descent of Man sequel is written.
•1882 – died and is buried in west minister abbey.
•Darwinian evolutionary theory is one of the 3 greatest forces that has helped
change the ways humans see themselves in the world. No one has changed the
way we think of ourselves as biological agents than Charles Darwin.
•Personality – domain in psych – life science – Evolution is the organizing frame
work for life sciences.
•Any theory of personality must be consistent with the evolutionary theory if it is
to be correct.
•3 basic idea as to where humans come from: 1. Evolution; 2. Creationism – the
idea that some divine agent created human life; 3. Seating theory – Aliens came
and planted humans in the Earth.
•Evolution theory is the only scientifically grounded theory that is capable of
counting for the variety of fxn design and the fxnality of design that we see in
living things and it is the only scientific theory that is capable of counting all the
•The foundation of classical evolutionary theory guides contempory evolutionary
theory and evolutionary psych. There are 3 basic elements to the evolutionary
process: 1. Variation; 2. Inheritance; 3. Selection
•Variation: the idea that we differ in our design features. We are diff physically
and psychologically; there is variation in design.
•Some of these design features are inheritable – they will be passed on to a certain
extent to one’s progeny. Some of these design features have a basis in our genesis
and therefore we pass it along to our progeny.
•Selection: Design features will to a greater/lesser extent CAN INFLUENCE OUR
CAPACITIES TO SURVIVE AND REPRODUCE. And if the design feature in
question is inheritable and it contributes to our survival and reproductive success
then it stands to reason that that trait will appear with increasing freq across
generation. So those traits that are heritable and that (+)’vely impact survival and
reproduction get passed on at greater rates than do alternative design features,
such that they propagate within features, and appear in increasing freq. If the
pressures remain same/if the environ challenges remain the same over a long
period of time, those traits that equip organisms to survive and reproduce best will
become so freq in the population that they will become typical of the species – so
virtually all members of the species will have the traits in question – these are
characterized as adaptations.
•Evolutionary Process: Natural Selection – is one of two evolutionary processes
that Darwin developed. It is the evolution of adaptive characteristics b/c of the
survival benefits bestowed on those having them. Ie) Products of a natural
selection – long neck of a giraffe – giraffes at an earlier stage in the evolution of
their species varied more dramatically in the lengths of their necks. Those giraffes
that had the longer necks were better equipped to reach the food at the very top of
the trees from which they derived their nourishment. So the giraffes with the
longest necks that had the greatest reach and ability to acquire food and
nourishment they as a result survived and reproduced more successfully than
those giraffes that had a smaller/shorter neck. So with each successful generation
those giraffes with shorter necks survived and reproduced less successfully and
neck length has a genetic basis and every generation that followed saw a depiction
of the species as one with an increasing freq of very long necks. It happened over
a very long time such that it is now characteristic of the species. It is now a very
fxnal design feature for the giraffes.
•Key elements: the design feature (trait) in question is contributing to the survival
of the organism.
•There are attributes and traits that some species appear to have, they seem to be
fxnal and at the very least same are species typical, but they seem to be a fly in
the face. Ex: brilliant plumage of the peacock. The brilliant plumage would
make it vulnerable to predation? There must be an alternative complementary
evolutionary process. This is sexual selection.
•Sexual selection – is the evolution of adaptive characteristics b/c of the
reproductive benefits bestowed on those having it. Some characteristics evolve
not b/c they contribute to survival but b/c they contribute for reproductive success
and may even be selective for despite of the fact that they impact survival
negatively. Some traits evolve the members of a species to survive and other
traits evolve because they allow member of a species to reproduce.
•2 subsidiary sexual selection processes – 1. intrasexual competition; 2. Intersexual
•Intrasexual competition – same sex competition. Very frequently members of the
same sex competing with each other in order to have priority of access to
members of the other sex. Quite frequently it is the males that are in competition
with the females. Those traits/attributes/design features that enable one to
compete successfully against one’s own sex (ie males against males) will
therefore ensure that that male reproduces more successfully. If the trait/attribute
has a heritable feature then its offspring will have that feature too. Ex: large
heavy deadly antlers of the male deer. Male deer (stags) sometimes compete
against other male deer to compete for female deer (does). The larger your
armour the better equipped you are to fight, the better equipped you are to fight
the more chances of securing mates; Given that the antlers have a genetic basis
the more successful males (largest antlers) pass them onto their male offspring.
There is a cost to having these heavy antlers. Having the heavy antlers
(advantages) might outweigh the costs it causes given their prevalence in the deer
•Intersexual selection: Often it is the males who are competing against each other
for access to the females. Females are in the position to choose their mate. If the
female population of a given species has some consensus about what’s desirable
in the males of a species, then those males that have the trait that is desirable will
be chosen as mates more often given that those attributed males get chosen more
often, they reproduce more often and produce more offspring. Ex: the more
brilliant the plumage is, the more likely it is to secure a mate, and therefore the
more likely it is to pass the plumage off to his offspring. This process has
occurred long enough for all the male population of the peacock to have the
•There are these evolutionary processes (natural selection processes, sexual
selection processes, intrasexual competition, intersexual selection etc.
•All of which are helping to shape the design properties and design features of all
species. Out of these evolutionary processes, some products emerge. 3 of the
products that are discussed are 1. adaptations; 2. spandrels; and 3. random effects.
1. Adaptations: those design processes selected and coordinated towards
solving recurrent problems. They are usually species specific – virtually
all members of the species have them. Ex: long neck of giraffe, large
brain in human.
2. Spandrels – are design properties that are not contribute directly to
adaptation. Rather they are linked at a genetic level to adaptations. So they get
carried along the evolutionary process. They can seem like adaptations but
are not. There are things can look species – specific but are not. They are
instead by-products of adaptations. These are design properties that are not
adaptive but rather are linked to adapted features/adaptive design properties.
They become incidentally incorporated into the design of an organism. Ex:
ears are adaptations. Ear lobes are not adaptations. They are spandrels – they
are things that happen to co-occur with ears. So they are typical of the human
species. Although all humans have earlobes, it doesn’t make them adaptive.
It just means that earlobes are connected to ears, and ears are adaptive; B/c
ears exist for the final significance, we all have earlobes as well. They are the
by-products of adaptations. It doesn’t mean they have any final significance
Evolutionary process: traces itself to the work of charles darwin, born in 1809 in england, degree in 1831 age 22. 1882 died and is buried in west minister abbey. change the ways humans see themselves in the world. 3 basic idea as to where humans come from: 1. Creationism the idea that some divine agent created human life; 3. There are 3 basic elements to the evolutionary process: 1. Selection: variation: the idea that we differ in our design features. We are diff physically and psychologically; there is variation in design: some of these design features are inheritable they will be passed on to a certain extent to one"s progeny. Some of these design features have a basis in our genesis and therefore we pass it along to our progeny: selection: design features will to a greater/lesser extent can influence our.