Week 1.
Lecture 1. 02/09/’25
Humans like to eat food high in sugar and fat, because in ancestral
environments, preferring calorie-rich foods increased survival chances. in
ancestral environments it was honey.
In evolutionary psychology the deepest why is the most important.
Why do people do certain kind of things?
Can we explain them with existing theories in psychology and the social
sciences?
Could we gain insights by thinking about humans as biological species,
subject to the same environmental pressures as other animals?
Evolutionary psychology: study of human behaviour, affect and cognition from
an evolutionary perspective.
Using evolution theory to understand why the human mind works this way and
how it has been designed.
In effect it means viewing humans as part of the animal kingdom, subject to the
same laws of evolution, natural selection, etc. seems continuous, but there is
really no plausible alternative.
Every species, including humans, has its own nature (a constellation of traits
typical for that species).
e.g. You own a dog and a cat. the dog is a very social animal (wolf) and is used
to eat very quickly (just in case the other dogs finish their food). A cat is a non-
social animal and takes their time to eat.
Charles Darwin (1809-1882)
The voyage of the Beagle (1831-1836) voyage on a ship, collecting
specimen as a scientist, he shipped them to England and analysed later
what he had found.
o He found different birds from different islands and found that they
had different snavels, based on what they eat. He had a theory:
there was one sort of bird, and they migrated to another island and
through natural selection and evolution the snavel got shaped the
way they could eat the food.
Book “on the origin of species” (1859)
NATURAL SELECTION AND THE SURVIVAL OF THE “FITTEST” (MOST ADAPTABLE)
Darwin quote: “As many more individuals of each species are born than can
possibly survive; and as, consequently, there is a frequently recurring struggle for
existence, it follows that any being, if it vary however slightly in any manner
profitable to itself, under the complex and sometimes varying conditions of life,
will have a better chance of surviving, and thus be naturally selected. From the
,strong principle of inheritance, any selected variation. Cuttety will tend to
propagate its new and modified form.”
Charles Darwin (1809-1882): great grandfather of evolutionary psychology
“in the distant future I see open fields for far more important researches.
Psychology will be based on a new foundation.”
Cutting the tail of a mouse has what effect on the next generation: the tail will
stay the same length. You don’t change their DNA. Whatever you do during the
lifetime doesn’t matter. Sometimes change over generations can happen,
because of a change in envorionment.
Components of natural selection
1. Variation: between individuals of the same species
2. Inheritance: some of the traits you have are heritable (length; eyes)
3. Selection.
The giraffe neck: how does natural selection really work?
There is individual variation in traits (longer neck)
Some traits variants allow their bearer to better compete for resources
(more and better leaves)
If these traits are inheritable then they are passed on from generation to
generation (long neck is heritable)
The result: individuals of a species become better adapted to their
environments over time. (over time all giraffes are born with a longer
neck).
Adaptation: functional solution to an evolutional problem that got solved by
natural selection.
a mechanism for evolution via natural selection: the gene.
Gregor Mendel (1822-1844). Monk, published in German.
did an experiment with peas: when you mix different peas, you get different
variations, with different genes.
Modern synthesis in biology: DNA discovery (Crick & Watson, 1953)
1. Mixing parental genes (sex)
2. Recombination of genes (double helix)
3. Random mutations.
a. Most of them are bad, but some can be good (like giving a giraffe a
long neck).
because it became colder and it turned into a savanne, the chimpanzees split
and it turned into the hominids. The chimpanzees stayed in the trees and the
hominids explored the land.
,Even though Neanderthals aren’t here anymore, we still have around 1-2%
Neanderthal DNA.
when homo sapiens migrated out of Africa, they encountered the
neanderthalens, had sex and that’s why we have a bit of DNA.
thousands of years ago homo sapiens were black 3-4.000 years ago. But
through evolution we became white, blond etc.
homo sapiens came into contact with the neanderthalers, neanderthalens
were good at hunting big animals, but because of climate change, they were
coming southern. Homo sapiens were in bigger groups so hunting was better and
that’s how they outlived the neanderthalens (small groups). a theory.
some intern change of genes when they were close to each other. more
plausible
Difference between natural and sexual selection
1. Natural selection: surviving benefit → characteristics that help you
survive better and adapt to the environment.
2. Sexual selection: reproductive benefit → characteristics that help you
being attractive and get more kin.
natural = surviving, sexual = reproductive success.
Two forms of sexual selection
1. Inter-sexual competition: traits that are passed on because they are
good at attracting opposite sex mates.
2. Intra-sexual competition: traits that are passed on because they are
good at winning same sex competitions for mates.
The human body is the product of evolution
Muscles, veins, organs, bones.
Incredibly complex.
Not perfect, but functionally adapted to certain environment.
, What drove the increase in hominid brain size
1. Ecological pressures (varying climatic conditions)
2. Technological changes (inventing and handling tools, weapons)
3. Social pressures (living in larger groups; social brain hypothesis)
a. Social brain hypothesis: we needed a bigger brain in order to live in
larger groups for predation; selfish hurt.
4. Cultural factors (better social learners).
Misunderstandings about evolutionary psychology
Human behaviour is genetically determined… but environments and
learning matter too
If it is evolutionary, we cannot change it… no we can shape our own future
Adaptations are optimally designed… not always in new environments
It’s an adaption so it must be good… no what is, is not what ought the
naturalistic fallacy.
Lecture 2. 04/09/2025
gene-environment interactions
Biologically innate: instincts or mechanisms
o Languagy capacity
o Desire to eat food
o Desire for social status
o Desire to be attractive
Culturally acquired
o Englisch, dutch, sign language
o Taste fir pizza, sushi, kroket
o Money, strength, publications
o Slim, voluptuous, tie, penis sheath
Harlow: not every behaviour can be learned as fast as some behaviour,
Lecture 1. 02/09/’25
Humans like to eat food high in sugar and fat, because in ancestral
environments, preferring calorie-rich foods increased survival chances. in
ancestral environments it was honey.
In evolutionary psychology the deepest why is the most important.
Why do people do certain kind of things?
Can we explain them with existing theories in psychology and the social
sciences?
Could we gain insights by thinking about humans as biological species,
subject to the same environmental pressures as other animals?
Evolutionary psychology: study of human behaviour, affect and cognition from
an evolutionary perspective.
Using evolution theory to understand why the human mind works this way and
how it has been designed.
In effect it means viewing humans as part of the animal kingdom, subject to the
same laws of evolution, natural selection, etc. seems continuous, but there is
really no plausible alternative.
Every species, including humans, has its own nature (a constellation of traits
typical for that species).
e.g. You own a dog and a cat. the dog is a very social animal (wolf) and is used
to eat very quickly (just in case the other dogs finish their food). A cat is a non-
social animal and takes their time to eat.
Charles Darwin (1809-1882)
The voyage of the Beagle (1831-1836) voyage on a ship, collecting
specimen as a scientist, he shipped them to England and analysed later
what he had found.
o He found different birds from different islands and found that they
had different snavels, based on what they eat. He had a theory:
there was one sort of bird, and they migrated to another island and
through natural selection and evolution the snavel got shaped the
way they could eat the food.
Book “on the origin of species” (1859)
NATURAL SELECTION AND THE SURVIVAL OF THE “FITTEST” (MOST ADAPTABLE)
Darwin quote: “As many more individuals of each species are born than can
possibly survive; and as, consequently, there is a frequently recurring struggle for
existence, it follows that any being, if it vary however slightly in any manner
profitable to itself, under the complex and sometimes varying conditions of life,
will have a better chance of surviving, and thus be naturally selected. From the
,strong principle of inheritance, any selected variation. Cuttety will tend to
propagate its new and modified form.”
Charles Darwin (1809-1882): great grandfather of evolutionary psychology
“in the distant future I see open fields for far more important researches.
Psychology will be based on a new foundation.”
Cutting the tail of a mouse has what effect on the next generation: the tail will
stay the same length. You don’t change their DNA. Whatever you do during the
lifetime doesn’t matter. Sometimes change over generations can happen,
because of a change in envorionment.
Components of natural selection
1. Variation: between individuals of the same species
2. Inheritance: some of the traits you have are heritable (length; eyes)
3. Selection.
The giraffe neck: how does natural selection really work?
There is individual variation in traits (longer neck)
Some traits variants allow their bearer to better compete for resources
(more and better leaves)
If these traits are inheritable then they are passed on from generation to
generation (long neck is heritable)
The result: individuals of a species become better adapted to their
environments over time. (over time all giraffes are born with a longer
neck).
Adaptation: functional solution to an evolutional problem that got solved by
natural selection.
a mechanism for evolution via natural selection: the gene.
Gregor Mendel (1822-1844). Monk, published in German.
did an experiment with peas: when you mix different peas, you get different
variations, with different genes.
Modern synthesis in biology: DNA discovery (Crick & Watson, 1953)
1. Mixing parental genes (sex)
2. Recombination of genes (double helix)
3. Random mutations.
a. Most of them are bad, but some can be good (like giving a giraffe a
long neck).
because it became colder and it turned into a savanne, the chimpanzees split
and it turned into the hominids. The chimpanzees stayed in the trees and the
hominids explored the land.
,Even though Neanderthals aren’t here anymore, we still have around 1-2%
Neanderthal DNA.
when homo sapiens migrated out of Africa, they encountered the
neanderthalens, had sex and that’s why we have a bit of DNA.
thousands of years ago homo sapiens were black 3-4.000 years ago. But
through evolution we became white, blond etc.
homo sapiens came into contact with the neanderthalers, neanderthalens
were good at hunting big animals, but because of climate change, they were
coming southern. Homo sapiens were in bigger groups so hunting was better and
that’s how they outlived the neanderthalens (small groups). a theory.
some intern change of genes when they were close to each other. more
plausible
Difference between natural and sexual selection
1. Natural selection: surviving benefit → characteristics that help you
survive better and adapt to the environment.
2. Sexual selection: reproductive benefit → characteristics that help you
being attractive and get more kin.
natural = surviving, sexual = reproductive success.
Two forms of sexual selection
1. Inter-sexual competition: traits that are passed on because they are
good at attracting opposite sex mates.
2. Intra-sexual competition: traits that are passed on because they are
good at winning same sex competitions for mates.
The human body is the product of evolution
Muscles, veins, organs, bones.
Incredibly complex.
Not perfect, but functionally adapted to certain environment.
, What drove the increase in hominid brain size
1. Ecological pressures (varying climatic conditions)
2. Technological changes (inventing and handling tools, weapons)
3. Social pressures (living in larger groups; social brain hypothesis)
a. Social brain hypothesis: we needed a bigger brain in order to live in
larger groups for predation; selfish hurt.
4. Cultural factors (better social learners).
Misunderstandings about evolutionary psychology
Human behaviour is genetically determined… but environments and
learning matter too
If it is evolutionary, we cannot change it… no we can shape our own future
Adaptations are optimally designed… not always in new environments
It’s an adaption so it must be good… no what is, is not what ought the
naturalistic fallacy.
Lecture 2. 04/09/2025
gene-environment interactions
Biologically innate: instincts or mechanisms
o Languagy capacity
o Desire to eat food
o Desire for social status
o Desire to be attractive
Culturally acquired
o Englisch, dutch, sign language
o Taste fir pizza, sushi, kroket
o Money, strength, publications
o Slim, voluptuous, tie, penis sheath
Harlow: not every behaviour can be learned as fast as some behaviour,
