PSYC18H3 Chapter 2: Chapter 2
Chapter 2 – Evolution of Emotions
Among the evidence that Darwin advanced for his theory of evolution was the similarity of human emotional
expressions to those of other animals.
Elements of an Evolutionary Approach
- Charles Darwin (1859) described evolution in terms of three processes.
o The first he called superabundance: animals and plants produce more offspring than are
necessary merely to reproduce themselves.
o The second he called variation: each offspring is somewhat different than others, and differences
are passed on by heredity.
o The third he called selection: those characteristics that allow better adaptation to the
environment are selected because they enable survival, and hence are passed on.
Selection Pressures
- For humans, selection pressures are features of the physical and social environment in which humans
evolved that determined whether individuals survived and reproduced.
- Some selection pressures involve threats or opportunities directly related to physical survival.
o Many systems such as our preferences for sweet foods and aversion to bitter foods, our
thermoregulatory systems, our fight and flight responses, developed in response to these kinds
of selection pressures.
- The elements that Darwin knew little or nothing of, but that we now know as genes, are passed during
reproduction from one generation to the next.
- Two kinds of sexual selection pressures determine who reproduces.
o Intersexual competition refers to the process by which one sex selects specific kinds of traits in
the other sex.
o Intrasexual competition is competition for mates within a sex.
▪ One could argue that the status dynamics of young men—the teasing, aggressive
encounters and tests of strength—serve a similar function: to determine who rises in
status, and who will be preferred by young women.
▪ Within intrasexual competition, those traits, whether they be strength, beauty, cunning,
emotional intelligence, or humor, that allow some to prevail are more likely to be
passed on to succeeding generations.
- Fitness—the likelihood of surviving and reproducing successfully—is increased for those who are
preferred by others as social partners = fitness is increased for those preferred as sexual partners
Adaptation
- Adaptations are genetically based traits that allow the organism to cope well with specific selection
pressures, and to survive and reproduce.
- Reproducing with healthy mates who are likely to help produce and care for offspring makes these
offspring more likely to be healthy, to survive, and to reproduce themselves.
o It is detrimental to devote resources to the pursuit of mates who might bear unhealthy offspring.
o Humans therefore find symmetrical faces more attractive than asymmetrical faces.
o Exposure to parasites early in development is associated with facial asymmetry, and in more
extreme cases, disfiguration.
o Our preference for facial symmetry guide us to potential mates who are resistant to parasites.
- Recent evidence suggests that the faces we find beautiful may also seem inherently good to us.
- fMRI scans found that activity in the medial OFC, a region involved in the processing of rewards, was
increased both by attractiveness and by ratings of goodness of an action
- Activity in the insular cortex decreased with both attractiveness and ratings of the goodness.
- Women are the child-bearers, they have to devote more resources to raising children than do men.
o Women report attraction to men of higher status, who will have more resources
- Men; it is to pass on genes they carry thru women who are physically healthy and best child-bearing age.
- Chivers et al. (2010) have found that heterosexual men’s attraction to pictures of naked women and of
heterosexual intercourse correlated strongly with measured blood flow in their genitals.
- Women were also aroused by such pictures, but they didn’t always report they were aroused mentally
when they were physiologically.
- The pressure for women to be choosy, to wait for mates with status and resources, may in part be
reflected in this tendency to base less of their sense of attraction on their physiological response
- An important determinant of whether one’s genes are passed on is survival during infancy
o The overwhelming love parents feel for their offspring, in response to baby-like features (large
forehead, big eyes, small chin), their smiles, coos, and laughs, their smells, and the softness of
their skin, overwhelms the many costs of raising children and increases the chances that genes
will be passed from one generation to the next.
- Not all human traits or behaviors are adaptations.
o Some human traits, from snoring to nervous leg jiggles, serve no apparent evolutionary function
and are better thought of as by-products.
- A trait that acquires a new function like this is called an exaptation.
- Andrew (1963, 1965) used this principle to propose how facial expressions in primates, including humans,
were developed from reflexes.
Natural Design for Gene Replication
- Genes help build the physiological and anatomical systems—neural networks, branches of the peripheral
nervous system, muscle groups—that are engaged in emotion.
- People tend to think that our genes are in our service, that we have received them from parents and that
we pass them on to our children. No!
- Modern evolutionary genetics has taught us that our genes pass themselves on to the next generation;
they reproduce themselves.
- The genes are not ours; our bodies are their means of passing themselves on.
- Based on the DNA from which they are composed, genes replicate.
- They copy themselves, and the copies become the genetic code for making the structure of plants and
animals they will inhabit in the next generation.
- There is no possibility of humans being immortal, but genes are potentially immortal.
- BUT genes can’t survive on their own.
- Plants and animals, including ourselves, are the vehicles they use to pass themselves on.
- Genes program us via a principal way; by our emotions.
- Equipped with the emotion of fear, we protect our bodies by avoiding dangers so the genes we carry will
be safe.
- By being emotionally drawn to food that is nutritious, attracted to sweetness and repelled by bitter-
tasting toxins that we reject in disgust, we build our bodies.
- By being interested in sex—in lust or in love—we enable our genes to pass themselves on to the next
generation.
- By means of the emotion of love for our children, we are enabled to take good care of them.
- By being decent to each other we create societies in which our children can grow up.
- In some instances our genes program our emotions so closely that when certain events occur we respond
in a reflex.
- In this reflex the programming of the genes was absolute.
o The avoidance of striking snakes has been so critical, it seems, that everyone who was our
ancestor had it wired in, and so do we, whether or not we ever confront a snake.
- Of course, these reflexive elements of emotional reactions are situated within complex social
relationships and are shaped by a particular culture
- At one end is the peremptory—the reflex—as with Darwin’s leap backward when the snake struck.
- At the other end are all those attractions and urges that our culture, or we ourselves, can modify.
o At the closely coupled end, the genes command us.
o In the middle are emotions like anger and some kinds of fear, which are sometimes compelling
but which we can sometimes modify.
- Our genes can program us by way of our emotions is that these effects can occur unconsciously.
- Unconscious effects—outside our immediate will and occurring for reasons about which we find it difficult
to reason—can affect us as emotional biases, impulses, and instinctual urges.
Three Social Motivations and One Antisocial Motivation
- We humans are social and hyper social: we live in families, societies developed cultures
- Three primary social motivations and one antisocial motivation:
o The social motivations and the antisocial motivation can be thought of as adaptations, selected
for during evolution.
Attachment
- The idea of attachment was conceived by John Bowlby (1951), who joined his research on children
separated from their parents with the theory of imprinting.
- Konrad Lorenz (1937) conceived the idea of imprinting to describe how, shortly after hatching from their
eggs, goslings learn to recognize and follow the first largish, moving, sound-making object in their
environment.
- Usually this is the mother goose, and that’s what evolution has arranged: a biological mechanism that
enables goslings to keep close to their mothers.
- But the recognition pattern is not closely specified: if no real mother appears, characteristics of the first
crudely plausible moving object are learned instead.
- In Lorenz’s studies, this object was sometimes himself.
- The effects are irreversible.
- Geese imprinted in this way didn’t recognize other geese. They made social signals to Lorenz.
- Attachment can be thought of as a human form of imprinting.
- Its function is to protect and care for the infant.
- The infant and caregiver cooperate to allow the infant to thrive.
- For our evolutionary forbears, threats to the infant included predators.
- Nowadays, parents worry about germs, busy streets, and falling down stairs.
- Bowlby also proposed the idea of the mother as a secure base.
- When the baby starts to move about, he or she can explore the features of the new environment when
the mother is present: the baby can retreat to her if necessary, and she keeps a watchful eye open.
- The functioning of the mother as a secure base continues into adolescence
- Trust, of the kind emphasized by attachment theorists as well as theorists of stages of emotional
development, includes confidence that one is, and can continue to be, safe.
- Mary Ainsworth (1967) made naturalistic studies of babies and mothers in Uganda, where she discerned a
set of behavior patterns that young children showed when they were with their mothers but did not show
with anyone else.
Document Summary
Among the evidence that darwin advanced for his theory of evolution was the similarity of human emotional expressions to those of other animals. For humans, selection pressures are features of the physical and social environment in which humans evolved that determined whether individuals survived and reproduced. The elements that darwin knew little or nothing of, but that we now know as genes, are passed during reproduction from one generation to the next. Two kinds of sexual selection pressures determine who reproduces. Intersexual competition refers to the process by which one sex selects specific kinds of traits in the other sex. Fitness the likelihood of surviving and reproducing successfully is increased for those who are preferred by others as social partners = fitness is increased for those preferred as sexual partners. Adaptations are genetically based traits that allow the organism to cope well with specific selection pressures, and to survive and reproduce.
