Evolution and Individual differences

PAGE
02
Evolution is the change of
inherited characteristics
within a population over
time through natural
selection, which may
result in the formation
of a new species.
EVOLUTION EVOLUTION
BEFORE DARWIN
Life has existed on Earth for a long
time
Organisms have changed since
the dawn of life.
Many extinctions have
happened since life began.
Fossil evidence, embryology
and comparative anatomy show
similarities between related species
and suggest a common ancestor.
Mendel’s work with genetics
showed how genetic elements are
passed through generations.

PAGE
04
(1744-1829)
Born in Bazentin-le-Petit, France
Joined the French Army at 17
when his father passed away.
He studied plants in his free time
After 7 years he was injured and
forced to leave.
He studied botany &
medicine
In the age of 34 he wrote a
book on plants Flore
Francaise.
a) Organisms tend to increase in
size and complexity with time
b) Changes in environment
made special demands on
organisms. Formation of new
organ in the body is the
results of a specific need felt
by the animal
c) The extend of the
development of organs and
their efficiency is proportional
to their use and disuse of the
organs.
d) The observable characteristic
acquired by the parents
during their lifetime can be
transmitted through
reproduction to the offspring.

PAGE
06
Lamarck noticed that
organisms adapted to a
particular place had well
developed specialised organs
For example a carnivore will
have long canine teeth to grip its
prey
He proposed that if an organ
is used a lot it will develop and
strengthen
If it is not used it will
degenerate
He called this the law of use
and disuse
Small non-functional
organs (vestigial organs)
Comparative anatomy
showed that these organs
resembled those which
were much more developed,
with particular functions, in
other species
e.g. the appendix in
humans, the internal hind
limbs of whales, and the
internal legs of some
species of snakes (Python
and Boa constrictor)

PAGE
10
Lamarck’s most
famous illustration
was using the giraffe
as an example
 The long neck of the
giraffe has evolved as a
result of generations of
giraffes stretching
their necks to feed
on the leaves of tall
trees due to food
shortage
 Each generation
has transmitted to
its offspring a small
increase in length
caused by continual
stretching
The modern giraffe thus has a
very long neck due to
inheritance of the acquired
characteristic

PAGE
12
Lamarck’s theory required
adaptation to create new
variations
This was followed by the
inheritance of these
characteristics
The argument was over
when Mendel’s laws of
genetics were rediscovered
at the end of the 19th
century
 Variations are due to
hereditary traits passing
from one generation to the
next in predictable
frequencies
Darwin’s theory requires
random hereditary
variation first, followed by
selection of the variations

PAGE
14
Characteristics acquired
during the lifetime of a
parent are not passed onto
the offspring
 An athlete who develops
a large muscle mass
through training does not
have children who already
possess this large muscle
mass
Ernst Haeckel: In an
attempt to disprove
Lamarckism he is said to
have cut off the tails of mice
for several generations
The babies born from this
line of tailless mice still grew
tails as long as their
ancestors
 This was not exactly a fair
test as the mice had not
stopped using their tails in an
attempt to adapt to their
environment

PAGE
16 In 1820,Spencer was born in
Derby, England on 27 April
In 1837 he began work as a
Civil engineer for a railway,
an occupation he held until
1846.
From 1848 to 1853, Spencer
worked as a writer and
subeditor for The Economist .
In 1851 Spencer's first book,
Social Statics to Human
Happiness appeared.
Upon the death of his uncle
Thomas, in 1853, Spencer
received a small inheritance
which allowed him to devote
himself to writing without
depending on regular
employment.

PAGE
18
In 1855, Spencer
published his second
book,
The Principles of
Psychology.
 As in Social Statics
Spencer's health
significantly
deteriorated in the last
two decades of his life
 he died in relative
seclusion, following a
long illness, on
December 8, 1903
Spencer took the theory of
evolution one step beyond
biology and applied it to say that
societies were organisms that
progress through changes similar
to that of a living species. It was
Spencer's philosophy that
societies (like organisms) would
begin simple and then progress
to a more complex form.
Spencer also found similarities
between animal organisms and
societies in that both had three
main systems.

PAGE
20
The first system is the
regulative system. In animals,
that would be the central
nervous system. In societies,
it would be a government that
regulates everything. The
second system is the sustaining
system.
For animals, that's the giving
and receiving of nourishment.
For societies, that would be
industry - jobs, money,
economy and those sorts of
things.
The third system would be
the distribution system.
In animals, that would be the
veins and arteries. In societies, it
would be roads, transportation,
internet anything in which
information and goods and
services are exchanged.

PAGE
22
It was Herbert Spencer, not
Darwin, who coined the
phrase 'survival of the
fittest' due to the fact that he
believed human behavior was
designed in a way that strives
for self-preservation. Darwin
later used the term 'survival of
the fittest' in his edition
of Origins of the Species.
The theory of social
Darwinism created the
thinking of the 'survival of the
fittest' as that the strongest and
the fittest should survive and
flourish in society, and the weak
should be allowed to die out.
 This allowed Spencer to
believe that the rich and
powerful became so because
they were better-suited to the
social and economic climate of
the time.
 He believed it was natural or
normal that the strong survived
at the cost of the weak.

PAGE
24
•Social Darwinists held that
the life of humans in society
was a struggle for existence
ruled by “survival of the
fittest,” a phrase proposed by the
British philosopher and
scientist Herbert Spencer.
•The humans in society, like
other animals in their natural
environment, struggle for
survival, and only the most fit
survive
•According to Spencer, if the
principles of evolution
are allowed to operate
freely, all living
organisms will
approximate perfection,
including humans.
•The best policy for a
government to follow, then,
is a laissez-faire policy that
provides for free competition
among its citizens.

PAGE
26
The concept of adaptation
allowed him to claim that
the rich and powerful
were better adapted to
the social and economic
climate of the time, and
the concept of natural
selection allowed him to
argue that it was natural,
normal, and proper for the
strong to thrive at the
expense of the weak.
After all, he claimed, that
is exactly what goes on in
nature every day.
However, Spencer did not
just present his theories as
placing humans on a
parallel with nature.
Not only was survival of the
fittest natural, but it was also
morally correct.
Indeed, some extreme
Social Darwinists argued that
it was morally incorrect to
assist those weaker than
oneself, since that would
be promoting the survival
and possible
reproduction of someone
who was fundamentally
unfit.

PAGE
28
 Social Darwinism applied
to a social context,
It provided a justification
for the more exploitative
forms of capitalism in which
workers were paid
sometimes pennies a day
for long hours of
backbreaking labor.
Social Darwinism also
justified big business'
refusal to acknowledge
labor unions and similar
organizations, and implied
that the rich need not
donate money to the
poor or less fortunate,
since such people were less
fit anyway
In its most extreme forms,
Social Darwinism has been
used to justify eugenics
programs aimed at weeding
"undesirable" genes from
the population; such programs
were sometimes accompanied
by sterilization laws directed
against "unfit" individuals.
The American eugenics
movement was relatively
popular between about ,
during which 24 states passed
sterilization laws and Congress
passed a law restricting
immigration from certain areas
deemed to be unfit

PAGE
30
The theory was used to
support laissez-
faire capitalism and
political conservatism.
 Class stratification was
justified on the basis of
“natural” inequalities among
individuals, for the control
of property was said to be a
correlate of superior
and inherent moral attributes
such as industriousness,
temperance, and frugality
At the societal level,
social Darwinism was used as a
philosophical
rationalization
for imperialist, colonialist,
and racist policies, sustaining
belief in Anglo-
Saxon or Aryan cultural and
biological superiority.

PAGE
32
Charles Darwin was born in
England on February 12,
1809. His family was
educated and well to do (his
grandfather was the maker of
Wedgwood china).
 Darwin studied medicine at
Edinburgh University but later
switched to divinity at Cambridge.
 In 1831, he joined a 5 year
scientific expedition on the survey
ship HMS Beagle as their
geologist.

PAGE
34
 As a naturalist, it was his job to
observe and collect specimens of
plants, animals, rocks,
and fossils wherever the
expedition went ashore
Darwin was fascinated by
nature, so he loved his job
on the Beagle. He spent
more than 3 years of the 5-
year trip exploring nature on
distant continents and
islands.
By the time Darwin
finally returned to
England, he had become
famous as a naturalist
While he was away, a
former teacher published
Darwin’s accounts of his
observations.

PAGE
36
During the long voyage, Darwin
made many observations that
helped him form his theory of
evolution. For example:
He visited tropical rainforests
and other new habitats where he
saw many plants and animals .
This impressed him with the great
diversity of life.
He experienced an earthquake
that lifted the ocean floor 2.7
meters (9 feet) above sea level.
He also
found rocks containing fossil
sea shells in mountains high
above sea level.
These observations suggested
that continents and oceans had
changed dramatically over time
and continue to change in
dramatic ways. He dug
up fossils of gigantic extinct
mammals, such as the ground
sloth
He visited rock ledges that
had clearly once been
beaches that had gradually
built up over time. This
suggested that slow, steady
processes also change
Earth’s surface

PAGE
38
Darwin’s most important
observations were made on
the Galápagos Islands . This is
a group of 16 small volcanic
islands 966 kilometers (600
miles) off the west coast of
Ecuador, South America.
Individual Galápagos islands
differ from one another in
important ways. Some are rocky
and dry.
 For example, the giant
tortoises on one island had
saddle-shaped shells, while those
on another island had dome-
shaped shells
 Others have better soil
and more rainfall. Darwin
noticed that the plants
and animals on the
different islands also
differed
People who lived on the islands
could even tell the island a turtle
came from by its shell. This
started Darwin thinking about
the origin of species. He
wondered how each island came
to have its own type of tortoise.

PAGE
40
One of the most
productive marine food webs
on the planet is located on the
Farallon Islands, just 28
miles off the San Francisco,
California coast. These
islands also host the largest
seabird breeding colony in the
continental United States, with
over 300,000 breeding
seabirds. The islands
are known as the
Galapagos of
California.

PAGE
42
Darwin observed many
organisms including finches,
tortoises and mocking birds,
during his five week visit to
the Galapágos Islands, near
Ecuador in the Pacific Ocean.
He continued to work and
develop his ideas once he
returned from his voyages.
Darwin's theory of evolution
challenged the idea that God
made all the animals and
plants that live on Earth, which
contradicted the commonly held
Christian views of his era. He
did not publish his scientific work
and ideas until 28 years after his
voyage.

PAGE
44
Darwin proposed the
theory of evolution by
natural selection.
Darwin proposed that:
individual organisms within
a particular species show a
wide range of variation for a
characteristic
individuals with
characteristics most suited to
the environment are more
likely to survive to breed
successfully
the characteristics that
have enabled these
individuals to survive are then
passed on to the next
generation
This theory is called
natural selection.

PAGE
46
Another scholar of the time,
Thomas Malthus , studied
populations and had a great
impact on Darwin’s understanding
of finches, other organisms, and
his theory of evolution.
Malthus believed that given
unlimited resources, a population
would grow exponentially.
Under normal conditions, a
natural population would be
limited by food, water, habitat,
etc. resulting in a balancing of
population numbers.
 Influenced by the ideas of
Malthus, Darwin proposed a
theory of evolution occurring by
the process of natural
selection.

PAGE
48
The animals (or plants) best
suited to their environment are
more likely to survive and
reproduce, passing on the
characteristics which helped
them survive to their offspring.
Gradually, the species changes
over time
Darwin worked on his
theory for 20 years. After
learning that another
naturalist, Alfred Russel
Wallace , had developed
similar ideas, the two made
a joint announcement of
their discovery in 1858
Alfred Russel Wallace was a great
admirer of Darwin and a fellow
naturalist, who independently
proposed the theory of evolution by
natural selection. Wallace produced
scientific journals with Darwin in
1858, which prompted Darwin to
publish On the Origin of Species
the following year.

PAGE
50
In 1859 Darwin published 'On
the Origin of Species by Means
of Natural Selection'.
The book was extremely
controversial, because the logical
extension of Darwin's theory was
that Homo sapiens was simply
another form of animal.
The three core principles of
evolution –
variation, heredity, and
differential fitness –
crystalized in the 1970s, still
serve as a conceptual
benchmark for the theory of
evolution by natural selection

PAGE
52
Evidence of
evolution
The fossil record
•Physical remains of
organisms.
Geographical
distribution of living
species
•Common ancestor
species
Homologous
body structures
•Implies similar
genes
Similarities in early
development
•Implies similar
genes

PAGE
54
Francis Galton was an explorer
and anthropologist known for
his studies in eugenics and human
intelligence.
.He was born on February
16, 1822, and grew up in a
wealthy family near
Birmingham, England. At
an early age, he began to show
great intellectual promise.
Sir Francis Galton Coined the term
in 1883, from Greek well born
Cousin of Charles Darwin
Concluded that traits like
intelligence were inherited
Entered Cambridge to obtain a
medical degree, but
graduated with a liberal arts
degree instead.
Traveled extensively in Africa
and the Middle East. Produced
first accurate maps of central
Africa.
Began corresponding with his
cousin Darwin in 1853

PAGE
56
Awarded a Fellowship at
the Royal Geographical
Society.
Drew some of the first
weather maps and
discovered the
importance of low an
high pressure
gradients in weather
prediction.
Invented several
instruments to measure
various
meteorological factors.
Pioneered the use of
finger prints to identify
individuals
It was widely held in Victorian-
era England that the aristocracy
was the product of good
breeding.
When The Origin of Species
came out in 1859
Galton used evolutionary theory
to develop his own ideas
concerning individual
differences.
Study of Intelligence,
Hereditary Genius, 1869
Thesis natural ability,
eminence, and
inheritance
Evidence
 normal distribution
and family pedigrees
Implication eugenics

PAGE
58
During Galton's time
DNA, genes and
chromosomes were
unknown.
Darwin had proposed
that the mechanism of
inheritance was
pangenesis, in which
gemmules in bodily fluids
mixed during mating.
Galton tested this in a
series of experiments
involving blood
transfusions in rabbits.

PAGE
60
The Survey In the 1870s
Galton wrote a questionnaire
and distributed it to 180
fellows of the Royal Society.
The survey asked respondents
to describe their
personalities, physical
attributes, family
characteristics and the details
of their up-bringing.
English Men of Science Their
Nature and Nurture
(1874/52)
Galton developed a
mathematical equation for
measuring the strength and
direction of the
linear relationship between
two variables.
His student Karl Pearson
developed the equation
that we use today.
The Pearson Product
Moment Correlation
Coefficient is used in
Behavioral Genetics.
The correlation
coefficient is generally
denoted as r

PAGE
62
The Twin Study
Galton was the first to use
twins to investigate
hereditary questions.
Galton sent questionnaires
to 94 pairs of twins.
Eugenics
The concept that society
should take active steps
towards improving its
genetic material.

PAGE
64
Galton believed that society
should promote the
reproduction of talented and
intelligent
individuals Positive Eugenics.
He also believed that society
should restrict the
reproduction of below average
individuals
Negative Eugenics.
To that end Galton
founded a
Anthropometric
Laboratory in 1880 and The
Eugenics Society in 1908.
The Eugenics movement
found a sympathetic ear in the
United States

PAGE66
Keenness of Sight and of
Hearing Color Sense
Visual Acuity Breathing
Power Reaction Times
Strength of Pull and of
Squeeze Force of Blow Span
of Arms Height, both
standing and sitting Weight
During the early 19
century it was held that the
environment contributed to
degeneracy.
Onanism
After the publication of Galton’s
work the view turned towards
heredity as the casual factor.
Rediscovery of Mendel’s work
Charles Davenport- Initially
interested in agricultural genetics.
Developed the lab at Cold
Springs Harbor
Several decent studies on eye
color

PAGE
68
The Big Fear Highly desirable
families have few children. Less
desirable families have more.
Problem If behavioral traits are
inherited how does the eugenicist
identify the good ones from
the bad?
Problems with measurement
Subjectivity
Alcoholism
Sexual immorality
Wanderlust
Feeblemindedness
Degeneracy

PAGE
70
(1860-1944)
Cattell was one of the first
students to get a Ph.D. with
Wundt, then he was
appointed to Cambridge.
He was strongly influenced
by Galton, and like Galton
measured everything he could
about himself.
In 1888, Cattell founded a
lab at the University of
Pennsylvania using Galtonian
measures with students but
moved to Columbia College in
1891.He discussed 10 mental
tests in “Mental Tests and
Measurements,” published
in Mind – The Freshman
Test

PAGE
72
The 10 tests included:
Dynamometer pressure,
Rate of Movement,
Sensation- Areas, Pressure
causing Pain, Least
Noticeable Difference in
Weight, Reaction-Time for
Sound, Time for Naming
Colours, Bi-Section of a 50-
cm. Line, Judgment of 10
Seconds Time, Number of
Letters Remembered on One
hearing.
Experimental research on
judgments of relative rank, such
as shades of gray rank ordered on
brightness.
Leading psychologists ranked
those in their profession.
Wissler found no correlation
between the tests. These tests
were abandoned in favor of
better mental measurements

PAGE
74
Individual intelligence individual
means single ,separate
Individual person separate
from other people and
possessing his or her own
needs or goals ,rights and
responsibilities
Intelligence intelligence as the
power of perceiving
,learning ,understanding
and knowing
The ability to use memory
knowledge experience
,understanding reasoning ,
imagination and judgment
in order to solve problem

PAGE
76
As psychologists
investigated different areas of
human behavior, they began
to look for ways in which the
science could be used to help
people. The first modern
intelligence test was
devised by
in 1905 at the
request of the French
education authorities.
 In 1881, the French
Government introduced
compulsory schooling for all
children.
This meant that slow learners,
who had originally been kept at
home, now had to attend school.
Binet devised a test which
measured ability and considered
that age of the child being tested
He devised the concept of
mental age which is the
individual's mental development
in relation to others

PAGE
82
Charles Spearman
postulated two types of
intelligence that account for
test scores:
 general intelligence or g
special intelligences, or
s,
which are the specific skills
and knowledge needed to
answer the questions on a
particular test.
 G Factor Developed the g factor,
which stood for general intelligence,
He believed that this single g factor
was responsible for each type of
mental ability

PAGE
84
Spearman did not believe in
separate intelligences like
musical or analytical, but just
one overall general
intelligence.
If you received a score of 120
on an IQ test then this would
be your indicative of your g
factor. Since your g factor is
high, then no matter what
profession or career you chose
you would be successful.
Most people know a person
who may be intelligent in
math, but struggle with verbal
abilities. In other words, even
people that are intelligent in
one area may struggle in
another area, which proved
Spearman’s theory wrong

PAGE
86
“Spearman’s successor”
His life’s work was fixated
on the notion that
intelligence is heritable.
Gould says: Burt’s
conclusions were
distorted, namely his
proof that intelligence is
innate
The 1909 study is logically
flawed, as well as statistically
flawed
Charles Spearman’s two-factor
theory, the g and s, was created to
study and generalize human-
societal relationships. Cyril Burt
wished to use this theory of his
predecessor's to rank and sort pupils
because they “had to be guided
toward professions by identifying
strengths and weaknesses in more
specific areas” Thus, Burt created the
four-factor theory.
g—the first component of
correlation found in mental
testingGroup Factors—subordinate to
g, but above ss—attributes of a single
trait measured on all occasions
Accidental Factors—attributes of a
single trait measured on one
occasionGroup factors “cover
different abilities according to
their form of content” .

PAGE
88
Born August 14, 1866
PhD in psychology from
Clark University Director of
Research at the Training
School for Feeble-minded
Girls and Boys
 Translated the Binet-
Simon intelligence scale
into English
Established the first
laboratory for the
psychological study of
mentally retarded persons
Helped
draft the first American law
mandating special education
Was a proponent of the
hereditarian position

PAGE
90
Goddard’s view on
intelligence was derived from
Mendelian genetics
• Believed that
feeblemindedness was
caused by the
transmission of a single
recessive gene
• Believed that those who
were feebleminded were
inferior
•Goddard argued that society
should keep feebleminded
people from having children,
either through institutional
isolation or sexual
sterilization. As a result of its
seductive mix of science and
ideology, Goddard's book became
a favorite among eugenicists. As
such, Goddard's views were part
of a dark chapter in American
history.
•Goddard was a far more
complex and nuanced
individual than this brief
account implies. His papers,
housed at the Archives of the
History of American
Psychology at the
University of Akron
•Goddard concluded that a
variety of mental traits were
hereditary and that society
should limit reproduction by
people possessing these
traits

PAGE
92
•Lewis Madison Terman
was an eminent American
psychologist who is most
noted for his seminal studies
of children of high
intelligence
•Terman defined intelligence as
"the ability to carry out
abstract thinking" and used the
label IQ or Intelligence
Quotient.
•Invented the Stanford-Binet
IQ Test
•He revised Binet's test to work
for large numbers of people in an
attempt to measure what he
thought was inherited
intelligence.
•Worked with Maslow at U
Wisconsin

PAGE
94
 (1886–1939)
wrote 25 books on
psychological topics and
served as president of the
American Psychological
Association in 1927
 Challenged misconceptions
about women
 concentrated her attention
on the education of gifted 1926
she published Gifted
Children, which became
the standard text in schools of
education for many Years
Children Above 180 I.Q. was
published in 1942

PAGE
96
(1876–1956)
dreamed of
becoming a
medical
doctor
elected president of the
APA in 1917
Established comparative
psychology with J.B Watson
In 1912 took job of director
of psychological research
and used Binet-Simon
scale for clinical
diagnosis
World War I in 1917, Yerkes
was president of the APA
Yerkes and other psychologists
developed an Army Alpha test
for literate recruits and an Army
Beta test for illiterate or non-
English-speaking recruits
The war ended in 1918, and the
testing program was terminated
in 1919, by which time more
than 1.75 million individuals
had been tested

PAGE
98
Results of Army testing
programs and concerns for
nations intelligence
Yerkes (1923)believed that
many of the nation’s ills were
being caused by people of low
intelligence and that
immigration policies
Terman and Yerkes argued
Test performance is
determined more by
education and personal
experience than by
inheritance
Herrnstein and Murray
organize their book around six
conclusions, or points, about
intelligence that are “beyond
dispute.”
When 24 prominent researchers
in the field of intelligence were
asked to define intelligence, they
provided 24 different definitions
Central to the problem is the
issue we introduced with
Spearman and Binet: Is
intelligence one
generalized factor or a
collection of many
different attributes?

PAGE
100
U.S. psychologists
revisited the idea that intelligence
was best understood as one factor
(Spearman’s g)
Thurstone, 1938 suggests
seven intelligence factors
Robert Sternberg’s
(1986) three factor model
has been widely embraced in
recent years, essentially
accepting
the traditional factor, but
including considerations
for experience and context.
Still, there is no universally
agreed upon answer to the
question

PAGE
102
Quinn McNemar
(1900–1986;
 APA president in
1964),
Anastasia (1908–2001
 APA president in
1972)
Paul Meehl (1920–
2003; APA president
in1962)
made important
contributions to
psychometrics.
(1896–1981)
Wechsler was
born an East
European Jew
During WW I,
Wechsler served as
a volunteer
scorer of the IQ
tests being
administered to
U.S. soldier
Wechsler resolved some of
the psychometric issues that
had been identified in the
original Stanford–Binet
and the Army Alpha and
Beta

PAGE
104
developed a new intelligence
test to better understand his
adult clients just before WW II
Wechsler Revised his test
during and after WWII,
eventually producing both the
WAIS (Wechsler Adult
Intelligence Scale) and
WISC (Wechsler
Intelligence Scale for
Children)
WAIS and WISC along
with the Stanford–Binet
remain the most widely
used.

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