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Chapter 2

PSYC18H3 Chapter Notes - Chapter 2: Facial Symmetry, John Bowlby, Social Status

Course Code
Michelle Hilscher

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Chapter 2: Evolution of Emotions Naela. S
evolution- theory of how species developed, has become central concept of biology; offers
insight into nature of emotions
Darwin advanced his theory of evolution by showing similarity of human emotional
expressions to those of other animals
Elements of an Evolutionary Approach
In Origin of Species, Darwin described evolution in 3 processes:
1. superabundance: animals & plants produce more offspring than are necessary merely to
reproduce themselves
2. variation: each offspring somewhat diff than others & differences passed on by heredity
3. selection: those characteristics tht allow better adaptation to env't are selected b/c they enable
survival, & hence are passed on
3 imp. Concepts tht shed light on evolution of emotions will be discussed below
Selection Pressures
centre of natural selection are selection pressures: for humans these are features of physical &
social env't in which humans evolved tht determined whether individuals survived &
some selection pressures involve threats or opportunities directly related to physical survival
to survive, individuals need to find food/water, to stay at right temp., & avoid predation, disease
--> our preference for sweet foods & distaste for bitter foods, our fight and flight responses,
thermoregulatory systems developed in response to these kinds of selection pressures
two kinds of sexual selection pressures determines who reproduces:
1. Intersexual competition: process in which one sex selects specific kinds of traits in the other
sex (e.g. men/women prefer ppl with good character, b/c they will be generous, faithful so
through selection process traits related to good character will be selected for & likely to
become part of human design)
2. Intrasexual competition: competition for mates within a sex (e.g. stags lock horns & engage
in battles to find who is dominant & thus has access to mates)
--> those traits whether they be strength, beauty, cunning,emotional intelligence, or humor tht
allow some to prevail are more likely to be passed on to next generations
Nesse argued tht fitness- likelihood of surviving & reproducing successfully- is increased for
those who are preferred by others as social partners in same way tht fitness is increased for
those preferred as sexual partners
--> we're ultra-social species who's chances of survival rest on upon evolutionary influenced
capacities to form strong relationships
adaptation- genetically based traits tht allow organism to cope well with specific selection
pressures & to survive & reproduce
Table 2.1 -Examples of adaptations
Problem/pressure Adaptation
Avoid eating toxins Distaste for bitterness
Find healthy mate Perceive facial symmetry as beautiful

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Share costs of raising offspring Preference for male w/ status, resources
Find fertile mate Preference for mate w/ youthful appearance
Protect offspring Emotional response to baby-like cues
humans have 10,000 taste buds; preference for sweet tastes help identify foods of nutritional
value; when you eat turnip/cabbage you're getting sub-lethal dose of such toxins
--> distaste for bitter foods helps us to avoid toxins
reproducing w/ healthy mates who're likely to help produce & care for offspring makes these
offspring more likely to be healthy, to survive, & to reproduce themselves
--> as a solution to finding a spouse tht will have healthy offspring, humans find
symmetrical faces more attractive than asymmetrical ; facial symmetry= gives us mates who
have been resistant to parasites
we believe ppl who are physically attractive also have good character
women report attraction to--> men of higher status, have more resources
--> woman are child-bearers & have to devote more resources in raising children than men
men are attracted to --> physically attractive women (full lips, youthful skin, hourglass figure)
& child-bearing age
Chivers (2010): found tht men's attraction to pictures of naked woman & of intercourse
correlated w/ their physiological responses (measured blood flow in genitals)
pressure for woman to be choosy, to wait for mates with status/resources , may reflect in this
tendency to base less of their sense of attraction on their physical response
final example of adaptation is human preference for baby-like cues found in facial features of
stuffed animals, anime figures, & other humans
important determinant of whether one's genes are passed on is survival during infancy; human
babies are vulnerable
--> evolutionary theorists have argued tht our responses to baby-like cues ensure tht parents
help their offspring reach age of viability
love parents feel for offspring, in response to baby-like features (large forehead, bug eyes, small
chins), their smiles, laughs, softness of skin overwhelms the costs of raising & increases
chances tht genes will be passed
some human traits/behaviours are not adaptations; they serve no evolutionary function
--> they are called by-products: snoring, leg jiggles
evolution is tinkerer, & often provides old anatomical & behavioural features w/ new functions
--> a trait tht acquires a new function like this= exaptation
--> Andrew used this principle to show how facial expressions in primates & humans were
developed from reflexes:
--> many animals have reflex of flattening their ears (original function was to protect ears)
when they are startled/ are feeling friendly
--> humans can't retract their ears, but raising eyebrows, which occurs when ppl approach
one another during greeting, flirting
Natural Design for Gene Replication
from parents you inherited 23 pairs of chromosomes, which contain genes made up of DNA
altogether humans have 25, 000 genes: responsible for creating proteins in ur cells to help form
hands, fingers, facial muscles, circuits in brain, branches of your peripheral nervous system etc.
Modern evolutionary genetics – our genes pass themselves on to next generation; genes copy

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themselves & copies become genetic code for making structure of plants/animals they will
inhabit in next generation
for genes: plants, animals, including humans, are vehicles they use to pass themselves on
as genes vehicles humans are robots, programmed to behave in certain ways & by naturals
election have ↑ chances of survival
--> technologies of housing, medicine have enhanced our abilities to be really good robots
--> our socially based adaptation (which helps genes survive) involves us being decent to
each other + altruistic
genes program us --> by our EMOTIONS
humans are good vehicles :
--> through emotion of fear- we protect bodies by avoiding dangers so genes will be safe
--> being emotionally drawn to food tht is nutritious, sweet & repelling repelling bitter-tasting
toxins, we build our bodies
--> interest in sex, love, lust- enable genes to pass themselves on to next generation
--> by being decent to each other we create societies in which our children can grow up
issue: some instances our genes program emotions so closely tht when certain events occur we
respond in reflex:
-->the fear response seen in Darwin's jumping back from striking snake, is best example of his
principle tht modern human emotions derive from ancestors who lived if diff ways than we do
many of simple/automatic elements of emotions mite be thought of in same fashion-- soothing
touch of parent in response to child's distress calls, disgust in response to bad smell, reflex-like
arousing of male sexual organs
programming of our emotions/desires by our genes has a range:
--> one end is the reflex- e.g. Darwin's leap back when snake struck
--> other end, are attractions and urges – tht our culture, ourselves can modify
--> closely coupled end: genes command us
--> in the middle are emotions like anger, fear which are sometimes compelling but which we
can sometimes modify
genes can program us by our emotions: these effects can occur unconsciously- unconscious
effects- outside our immediate will & occurring for reasons about which we find it difficult to
reason- can affect us as emotional biases, impulses, instinctual urges
Three Social Motivations and One Antisocial Motivation
humans are social:
--> we are mammals which are characterized for being born live (not from eggs) & this is time
when we can't take care of ourselves thus we are given milk & nurtured by parents
--> we are hypersocial: live in families, in societies tht have developed cultures
--> key to most human emotions is tht they involve others
Aristotle -idea tht emotions are evaluations of events in relation to goals (motivations)
--> three primary social motivations & one antisocial motivation
attachment- Bowlby: psychological accompaniment of the physiological fact that as babies we
are nurtured with milk
imprinting- Lorenz: described how shortly after hatching from their eggs, goslings learn to
recognize & follow the first moving, sound-making object in their env't which is usually the
mother goose
--> in his study Lorenz removed mother and soon after they hatched the goslings imprinted on
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