The Evolving mind

 Mind The brain and its
activities,including
thought, emotion, and
behavior.
 Nature The contributions
of heredity to our physical
structure and behaviors.
 Nurture The contributions
of environmental factors
and experience to our
physical structure and
behaviors.
 Psychology The scientific
study of behavior and
mental processes.

 When we see a identical twins
we usually amaze over the
similarities..
 But if we see scientifically
they share the same DNA
…then why they are are not
completely same.. Why one
gets obses one doesnot..one
gets cancer one not..??
 Let us puzzle our minds and
try to solve and find the
reasons of difference.

We have the same set of
DNA in all the cells,yet
some becomes heart cells,
some liver cells, likewise
different kinds of cells are
formed.
The reason behind this is
that genes can be turned
on or off.
The genes which are not
turned off produce the
protein needed to built a
particular type of cell.

 Genes can also be turned
off by environmental
factors like whether we
smoke or drink ,our stress
level,what we eat etc.
 In mice, gene Agouti
produces yellow fur and
obesity when turned on
and brown fur and normal
weight when turned off.
 If pregnant mother mice
eat food containing
bisphenol-A. The BPA
seems to have turned on
the agouti gene.

 Thus, we can conclude that in case of identical
twins the difference between them as they
grow old is due to differences in their habits
which changes the way their genes are turned
on and off.
 Genes are not just the puppets or blueprints.
 Nor just the carriers of heredity.
 They are active during life span,they respond to
the environment.
 There are both cause and consequence of our
actions.

 Researchers have known for a long time that
victims of bullies often, but not always,
develop serious emotional problems later in
childhood or adolescence.
 Having a particular genetic profile involving
serotonin, one of the chemical messengers

 As we know that each cell in our body except
blood cells and sperm or egg cell have two
comlpete copies of human genome,that contain
instructions for building a human body.
 Your personnel set of instructions is called as
genotype which interacts with environment to
produce observable characteristic called
phenotype.

 A single human can produce 2^23 (8,388,608)
different combinations of his or her
chromosome.
 Inspite of this much potential variation , we
remain very similar to our genetic relatives.
 Relatedness is defined as the probability that
two persons share copies of the same allele
from a common ancestor.

 When factors other than genotype itself
produces changes in phenotype , its called as
epigenetic change.
 The environment can determine if and when a
particular gene is active.
 In one dramatic example it was observed that
the rats which were licked(similar to hug)by
their moms were calmer than the other rats
which were infrequently huged.
 By licking their pups,these mothers have
influence the expression of gene that determine
responses to stress hormone.

 The field of behavioural genetics attempts to
identify and understand the links between
genetics and behaviour.
 Behavioral geneticists are less interested in
genes we share with other species than in those
that make us different from them.
 Recent research points to difference between
humans and chimpanzee in a single gene ,the
Fox p2 that appears to have had a significant
effect on distinctly human behaviours including
spoken language.

 Behavioral geneticists often speak in terms of
the heritability of a particular trait, or the
statistical likelihood that variations observed
across individuals in a population are due to
genetics.
 Heritability is usually presented as a ratio of the
amount of variation observed in a population
due to genetics relative to the total amount of
variation due to both genetic and environmental
influences.
 For example, genes are responsible for us
having hearts, but there is no individual
variation in the population in terms of the
presence of a heart—we all have one.
Consequently, the heritability of having a heart
is 0.0.

 All variation in the population in terms of having or
not having a fatal neurological condition known as
Huntington’s disease is entirely due to genetics. If
you inherit a Huntington’s gene from one parent,
you will develop the condition, so the heritability of
Huntington’s is 1.0.
 Heritability always refers to populations, not to
individuals.
 Heritability cannot be assessed without taking the
environment into account some researchers
question the use of adoption studies for assessing
the relative influences of genetics and environment
on child development.
 These studies compare adopted children to their
biological and adoptive parents in an effort to
assess the relative impact of heritability.

 It is important to remember that genes encode for
proteins, not behaviors. Genes build proteins that
are used to construct brains, and brains may or may
not initiate the behavior of drinking alcohol.

 The human genome is the product of millions of
years of evolution, defined by modern
biologists as “descent with modification from
a common ancestor.”
 Charles Darwin proposed that species evolve or
change from one form to the next in an orderly
manner.
 Gregor Mendel (1822–1884), who discovered
ways to outline and predict the inheritance of
particular traits, like the color of flowers, in his
research on pea plants (Mendel, 1866).

 In addition to the process of natural selection
described by Darwin, evolution can result from
mutation, migration, and genetic drift.
 Type B blood is virtually absent in
contemporary populations of Native Americans,
most likely due to chance (Halverson & Bolnick,
2008).
 The handful of ancestors crossing the Bering
Strait 10,000 years ago appears to have
included no individuals with the Type B allele.
 Adaptation can refer to either the process or
the result of change due to natural selection.

 Although we can understand the advantages of
big, intelligent brains to survival, we do not
know why advances such as agriculture,
literacy, and urbanization have not been
accompanied by additional increases in brain
size.
 Genes involved with brain development appear
to have changed as recently as 6,000 years ago.
 IQ test scores have increased dramatically
worldwide over the last 100 years.
 It is likely that environmental factors, including
nutrition and education, might account for the
improvement.

 Behaviour can be adaptive but behaviour as a
phenotype is considerably more complex.
 Behaviour is not an anatomical structure like a
wing or an eye.
 In his Descent of Man, Darwin writes:
 The difference in mind between man and the higher
animals, great as it is, certainly is one of degree
and not of kind. We have seen that the senses and
intuitions, the various emotions and faculties, such
as love, memory, attention, curiosity, imitation,
reason, etc., of which man boasts, may be found in
an incipient, or even sometimes in a well-
developed condition in lower animals.

 A number of factors are believed to influence the
social behavior of any particular species, including
mating systems, the availability of resources such
as food, water, and shelter, the exposure to
predators, and competition.
 In typical environments, individual animals are
likely to come into contact with others, leading to a
variety of possible interactions and outcomes.
 In altruism, one individual sacrifices himself or
herself to benefit another individual.
 A honeybee sting, which is suicidal behavior on the
part of the bee in an effort to protect its hive .

 Charles Darwin himself was puzzled by the apparent
sacrifice of some individuals that led to the survival
of the group.
 If altruism results in the destruction of the
individual with altruistic genes, why doesn’t this
behavior disappear?
 In cases of reciprocal altruism, it is customary to
help another individual when you can reasonably
expect the other individual to return the favor at
some future date.

 Sexual selection was Darwin’s term for the
development of traits that help an individual
compete for mates.
 Genghis Khan may have been the most prolific
human male in history. His distinctive Y
chromosome has been identified in 16 million
living men, or 0.5% of the world’s current total.
 Women have the ability to make very accurate
predictions of a man’s interest in children, simply
by looking at a photograph of his face.

 Sexual selection might occur in two ways. In
intrasexual selection (intra means “within”),
members of one gender compete with each
other for access to the other gender.
 In intersexual selection (inter means
“between”), characteristics of one gender
that attract the other might become sexually
selected.
 Evolutionary psychologists have argued that a
number of human traits might have been
subjected to sexual selection, including
humor and vocabulary.

 According to the researchers, environmental
influences, such as peer attitudes and
exposure to “Dad’s humor,” may have
dominated the development of each woman’s
sense of humor.
 Significant evidence points to a very
important role for humor in human mate
selection.
 Men were interested in women who
appreciated, rather than produced, humor,
while women were interested in men who
made them laugh.
 Women appear to signal their interest in a
man by laughing frequently ,whereas the
frequency of men’s laughter appears to be
unrelated to their judgment of a woman’s
attractiveness

 Producing a good joke requires sophisticated
cognitive skills, creativity,and the ability to
see situations from more than one point of
view, qualities that signal the good
intellectual and social functioning preferred
by females.
 According to evolutionary psychologists,
humor might be used by humans to attract
mates, because humor indicates intelligence.

 The human mind has been shaped by its
history.
 The evolutionary approach, suggests that
another type of compatibility is important
for relationships—a compatibility of genes
that contribute to the immune system.
 A cluster of genes known as the major
histocompatibility complex (MHC) appears
to be subject to sexual selection.

 A child with a heterozygous set of MHC genes
is better prepared to battle infections than is
a child with MHC genes that are similar to
one another.
 As a result, our children are more likely to
survive if we select a mate that has a
different set of MHC genes than we do.
 Short of asking potential mates to undergo
DNA testing,how are we supposed to
accomplish this?
 Different configurations of the MHC genes
produce distinctive body odors that are
easily detected and distinguished from one
another.

 When men and women were asked to rate
the pleasantness of the odors of T-shirts.
 They preferred smells associated with MHC
genotypes that were different from their
own.
 Gender did not play a role—smell preference
was not influenced by whether the T-shirt
wearer had been of the same or the opposite
gender as the perceiver.

The Evolving mind

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