The exam is cumulative, so you have to know everything from textbook chapters 115, everything from all the lectures, and all of caveman logic.
However, Professor Davis said there is a stronger emphasis (70%) on information post midterm, so textbook chapters 815, lectures starting from
learning onwards, and Caveman logic chapters 4 to the end (however, seeing as Caveman Logic doesn't exactly parallel the order in which we learned
everything I'd recommend reading the beginning as well if you haven't already).
Evolutionary Psychology – November 7, 2012
CHAPTER 11 –ABNORMAL BEHAVIOR
• € Cause of abnormal behavior?
o Very few of us would argue that demonic possession is the explanation however
there are some cultures/groups of people that believe this as the basis
o Majority of our society would opt for medical basis (eg. disease, illness,
etc) genetic basis (heredity)
o In both cases, implying the patient has NO CONTROL over their state
Large similarity between polar opposite views
Eliminates personal responsibility rationalize that it isn’t their fault that
External/internal causes beyond their control
o Morally questionable when one tries to justify harmful behavior with the ‘I’m
crazy I can’t help it’claim
• € Political correctness becomes compromised when reacting to/describing cases of
• € Normal can be a strictly statistical term ‘most people don’t do that’
o Hard to characterize parameters of abnormal
• € Mental illness introduces the medical law
• € Addictive behavior medical condition or something irresponsible?
o Eg. morbidly obese – medical disorder or a fat slob that can’t control their
o Eg. alcoholic in the gutter medical affliction or an irresponsible drunk?
• € Story about 450 lb guy prof brought to radio station for job:
o Difficult for him to get into car
o Interview went well (competent guy) and then left
o Wondered if staff would discuss his weight after he left despite its irrelevance
People began to downgrade his credentials, scrambling for reasons to
discredit his qualifications and not like him
• € Weight was not mentioned
Prof said “anyone notice he was fat?”
o We have attitudes toward abnormal properties whether we know it or not
If he had a medical excuse we would accept it more easily If he was just a food-loving guy we would judge him
• € DSM – diagnostic and statistical manual
o Meant to be theoretical because no consensus about cause-and-effect thus
parameters are fuzzy
o No one really knows how to treat these afflictions
o Freud is the only previous agreement in the DSM
o Largely economically driven need categories because these categories impart
a certain reality to these abnormal behaviors
Insurance issues – if it isn’t in the DSM, not obligated to pay for it but if it
is then there is compensation
Eg. Road rage syndrome – jerk on the road is now diagnosed with a
tangible disorder and receives treatment/compensation
• € Evolutionary psychological accounts for abnormal behavior are atypical:
1) These behaviors we categorize as abnormal are not disorders, but rather adaptive
defenses (parallel = fever/pain)
i. Not something gone wrong (despite discomfort they confer) something
gone right adaptive means they serve a purpose
ii. Eg. non clinical depression can be seen as beneficial when considering
adaptive value; conservation of energy resources to channel activity to
things that increase fitness
iii. Eg. anxiety advantageous in the Pleistocene but uncomfortable now
2) Abnormal behavior represents side defects that came along with genes that were
actually selected due to adaptive value
i. Clusters of genes that piggyback on other genes
ii. Genotype makes it to the next generation because of association with
genes that were selected
3) Frequency-dependent selection – eg. sociopathy – terrific strategy when it
is rare in the group
i. In a group of sociopaths (frequency increased), however, not
ii. Works at some optimal frequency, but when exceeded not effective
4) Results from absence or malfunction of a particular module
i. Eg. autism – person is missing some imperative module involved in
ii. Parallel defective colour vision system; something is missing/broken
in the module for vision
5) Mismatch between present environment and the Pleistocene
i. Eg.ADHD – advantageous in Pleistocene but incompatible with current
demands (formal schooling, fixed jobs etc)
6) Abnormal/maladaptive behavior really represents the extreme of the normal
distribution of some polygenic trait i. Observed behavior is way off the optimal value of the polygenic trait in
either direction (+/- 2 standard deviations from optimal trait value)
ii. Bound to get some crappy combinations (supposed to work on average)
when many genes are involved
o Eg. Guy working with rhesus monkeys found it was always the case in any
population of monkeys (over a lot of time conducting study) that ~60% of colony
are normal leaving 40% abnormal
Of this abnormal group: ~20% are depressed, shy, behaviorally inhibited
in some way while remaining 20% were impulsive/aggressive
Very stable/consistent finding, overtime and across colonies
o Appear to be unappealing phenotypes so why do these proportions persist over
Polygenic traits thus expect these deviations from optimal
value represents extreme/tails of normal distribution
He did not believe this decided that the absolute best thing any species
can have over time is variation(heritable diversity)
• € If not inheritable, doesn’t count/matter
• € Must maintain variation in gene pool because even if these
phenotypes are incompatible with this current environment, never
know what future environmental conditions/demands/selection
pressures will be
Need safety net in case adaptive demand/environmental filter shift
toward either extreme of trait because natural selection can only select
• € If alternatives are eliminated from gene pool, species will doomed
in new environmental conditions
Presently, bad for individual to be abnormal but good news for
the species group selection argument
• € Natural selection selects for the good of the individual not the
good of the species/group
• € NO EVIDENCE that this explanation is true
• € Hard to imagine how altruistic genes would prevail/not get selected out
o Logic suggest that these genes preclude survival/repro, which is the only way
that these genes can make it into next generation
o Altruists are necessary for the group faulty logic because argument for group
selection which is not how natural selection works
Examine common forms of mental illness:
• € Depression – incredibly common
o Evolutionary point of view – can be seen as a reasonable time out, withdrawal
from investing anymore energy/resources into futile endeavor Where is the threshold – where do you draw the line and stop trying; when
is it deemed futile?
Without some sort of limit, investing all energy into a task that is
definitively futile is very maladaptive when you don’t know where too
o ‘Quitting too soon’is also problematic
o Strips off rose colored glasses and gives more realistic view of ourselves and our
place in the world no semblance of self-deception
o Without depression, typically overestimate our status – we are above average
o SAD – seasonal affective disorder: temporarily restrictive depression,
determined by amount of sun at the time of year
Triggered by fewer hours of daylight; carbo-loading, excessive sleep
• € Evolutionary perspective – makes sense as an adaptation; light
hibernation – times back in the Pleistocene when it was good to
dial it back a little bit
Recognized treatment = light exposure
o PPD – postpartum depression: makes senses; evolved as a labor strike in order
to elicit more help from partner/kin in enormous task that lies ahead
Negligence will prompt other family members to take over
o Difference between evo and normal psyc – psyc looks at depression and says
that’s a chemical imbalance/something went wrong while evo says no this is the
way it should be (these are adaptive capacities)
o Morning sickness – commonly viewed as consequence of hormonal imbalance,
while evo says it is the body working better than ever
Heightened sensitivities work to reduce prenatal defects and allow better
development of fetus
System is working according to plan
Freudian explanation morning sickness is unconscious attempt to
vomit up the fetus
• € Suicide – evolutionary point of view notes that likelihood of suicide increases as one’s
capacity to promote their own reproductive success diminishes
o Accordingly suicide rates increase dramatically with age
o Pleistocene – people living together in small groups (almost invariably kinship
based groups) with fixed resources
o Old people in these groups contributed less and were a drain on the resources
(common phrase in suicide note = “didn’t want to be a burden on my children”)
Old people in Pleistocene were a burden on younger, reproductively-
viable members of the group
Not the case now but evo psyc examines the basis during conditions
where the adaptation would’ve evolved (Pleistocene) • € Sociopathy
o 3-4% of population in general (globally) are sociopaths
o In prison number jumps to ~20% of population
o Low or devoid of shame/guilt, charming, less emotionally responsive than
normal thus seek out sensory stimulation
o Crimes committed = exploitive nature, deceptive, embezzlement
o Lack a module for “what will people think” (other’s perception of them) and “ill
never be able to show my face again” (shame)
o Linda names 3 categories:
Small fixed % of individuals (the extremes on sociopath spectrum) that
are morally insane/perturbed wherever they lived
Other extreme says virtually everyone has a little sociopath in them
(tendency is there but not always active)
• € Sociopathy is significantly more frequent in men than women
• € Subclinical manifestation of this underlying genetic continuum is
evident in many of us becoming apparent only in times where
environmental circumstance makes an anti-social strategies more
o Sometimes it pays to be a sociopath
o Use it when you need it but make dormant when
o If possible ignore and avoid a sociopath very difficult to do because they are
Harder for sociopath to exploit others in prison because frequency-
dependent trait (loses effectiveness with higher frequency)
Do we have sociopath detector or will you fall victim to the charm?
o Steer them into appropriate jobs: examples
Seek sensation stuntman (do nothing but take physical risks), repo
man, certain classes of salesmen
• € Autism – 1 in 1000 people are autistic
o Commonly described as a social disease
Impaired in terms of giving and receiving social cues
o Characteristically lack a ‘theory of mind’
Do not comprehend that other people have their own intentions, thoughts,
desires, likes, dislikes
Important to read each other and pick up cues and modulate our own
behavior accordingly but they cannot do this (clueless)
o Used to be called mind blindness
o Do not read non verbal behavior o It is a key to our social existence to have ability to read nonverbal cues
o Evo psyc – evolved module that autistics do not have
Occasionally normal people employ this module inappropriately (eg.
anthropomorphism) attribute ideas/thoughts/attitudes to members of a
different species (eg. pets or even inanimate objects)
o Temple Grandin – most famous autistic person (female)
Thoroughly autistic but still highly verbal and educated and has a family
o Oliver Sacks – wrote about her in his book – described herself to him as an
anthropologist on mars
Attempts to makes sense of people around her without the unconscious
ease with which normal people do
When she observed children interacting in the playground noticed they
were engaged in social signaling, she is now aware of it but cannot
perceive it (she wondered if they were telepathic)
She evaluated humanity of a slaughter house by telling them which parts
were scaring the cattle the most
• € Began legislating things like this and gained government support
to enforce restrictions on all slaughter house designs
• € Good at reading animals but not people
• € Helped prof get his rats to cooperate said she could speak rat
(changes that he had to make to make them comply) in exchange
for him touring her around campus with a commentary of the
social cues of everyone around her
• € He translated people to her and she translated rat for him
• € She lacks one of the most fundamental core human abilities there
is interpretation of nonverbal interaction
• € She is one of the most sexually ambiguous people because cues
she gives off are ambiguous (we give off cues that allow people to
know if we are straight or gay)
• € Guy asked her what her sexual orientation was because impossible
o Testament to normal ability of reading non verbal
Nov 12 th
∙ Two kinds of personality disorders:
o Histrionic personality disorder:
Sociopaths are usually all male; a women sociopath would be one that has
histrionic personality disorder. Basically equalivant
Exaggerated attention seeking behaviour.
Sexually inappropriate behaviour
Easily influenced by others
To perceive to be more intimate that they really are
We could expect that there would be more differences because of the
differences in the reproductive.
Women’s strategy is “darling I need you so much” the male would say
“oh, this is good”
Often abandons children and leaves other children to take care of each
It is rare not to see these features in someone we know.And having some
of these features does not necessarily mean that you are a sociopath. It
would require all.
o Borderline personality disorder: Pattern of unstable interpersonal relationships where sig others are
alternatively unrealistically idealized and then unrealistically devalued.
They engage in reckless destructive behaviour
Intense fear of abandonment and become angry with separation
Insecure parental attachments from childhood.
On a quest for reliable figures to provide care that their own family failed
Self damaging behaviour and misery
∙ These personality types are not rare. So why hasn’t natural selection weeded them out?
o Natural selection is not looking for perfection. These genes must have some kind
∙ Genes associated with personality disorders spread.. What we do as human beings is
we remove the selection pressure. We say that we are going to make sure that everyone
survives, which lets a lot of crap through.And these people are allowed to make other
∙ But why did these disorders make it through when they didn’t remove selection pressure in
the placisticine era? Maybe borderline piggybacks on other traits. Maybe they are drop
dead gorgeous and therefore would have a good change of mating. There must have been
something about them that was worthwhile to keep around.
∙ FYI – an alone person was also known as a dead person.
∙ Nowhere do people have an equal desire for all members of their desired sex. Some are
∙ There are standard things that we look for; it is not up to us.And we should be good at
reading he cues that tell us about our potential mates.
∙ Back then; mating was the same as reproducing. Now there is a clear distinction.
Preferences/ideals are different for who they want to have sex with verses who they want
to have children with.
∙ Article: “women like the smell of dad, study finds.” Women are attracted to men that smell
like their father.
∙ The point of this chapter is that there are massive sex differences in human mating
∙ Two basic questions:
o What attracts you to the partners you choose?
o What accounts for the massive and reliable sex differences in mating strategies?
Clark experiment: Male and females are approaches by strangers by the
opposite sex. They have a brief convo and one of 3 questions is asked.
Would you go out with me tonight? Would you come up to my apartment
tonight? Would you go to bed with me tonight? Males and females would
not response differently to these questions. • € Data: Questions 1 showed no differences, question 2, 6% of
women said yes, question 3, 0% of women said yes and 75% of
guys said yes. Why? Because guys want to get laid. Is it how we
are raised? No. These numbers are identical cross-culturally. No
such culture exists where women are ten times more likely to say
yes to going to bed with a guy that they just met.
∙ Differences in reproductive rates lead to sex differences.
∙ Parental investment and sexual selection: sex that invests more in the offspring will be
more discriminating in mating. This is replicable in other species. The opposite is also
∙ There is no better example of why there would have to be a massive sex difference than
the kiwi bird. Every time the male kiwi ejaculates he produces enough sperm to
impregnate every female kiwi on the planet. The female kiwi she gets 3 eggs and they are
very big. They are not going to have the same sexual strategies because it is not a cultural
Nov 14 th
∙ With gay men, both partners have hundreds of partners. Gay women tend to have the same
number of partners as straight women. Basically, being gay doesn’t change anything. If
you are a guy you are going to act like a guy. Being gay you just don’t have a woman to
slow you down.
∙ Women’s investment slows down men’s reproductive advantage.
∙ In a perfect monogamous system men and women have equal reproductive rates. But there
is not anywhere on earth where you can find a perfect monogamous system. Monogamy
is recent and unnatural even thought it seems like it is to us because as long as we have
lived things have been that way.
∙ 85% of cultures on this world are polygamist and typically occurs in small groups
∙ BBC News online:
o Long term relationships are fundamentally dishonest, and it’s all the faulty of
o Scientists claim that monogamous relationships among many species including
humans, only persist because females have found a way to…
∙ Even in monogamous societies things like divorce, and infidelity bring us back to
polygyny. ∙ Men are much more likely to remarry after separation or divorce than women and typically
marry younger women.
o Therefore men get the fertile years of more than one woman.
∙ Women are choosier.
∙ What if the sex roles were reversed? When the males did the work (house work, raising the
kids, etc.). The prediction would be that then everything would be reversed in these rare
cases, which makes them stand out.
o Penguins, seahorses
o Fall… (Some animal)
Males make 90% the investment; females lay the eggs and then leave.
The females are larger than the males, more colourful, more competitive
for access to the males, sexual selection is enhanced for the females
∙ If you look at the whole scale and try to predict when males might help, it depends on the
degree of helpless of their young and degree of development.
o The need for biparental investment is increases in these cases where the
offspring is more helpless.
∙ For men investment means their recourses and for women it typically means their bodies.
o This difference effects what is desirable.
∙ There are classic sex differences in what we see:
o In general, guys are looking for good-looking young women who are good sex
partners and good baby makers.
o Women are looking for a man with good health, status, and resources.
o There is a difference between who you are looking for on a Saturday night and
whom you are looking for to make babies.
∙ Youth is a very good sign of reproductive potential. Young people think that they are in
control of their mind, but we have circuitry that drives our preferences. Denying this
existence on the basis of free will is not a good starting place.
∙ Women spend billions of dollars to reduce signs of are, because age is a signal of lack of
reproductive ability. Because subconsciously a man is driven to a women because of her
∙ Facial features that are universally perceives as beautiful also signal health and
reproductive ability and also your past medical record.
o Suggests that all of us are born symmetrical, and we lose it because of parasites,
and by the time we are 50 or 60 we becomes asymmetrical and therefore become
∙ The biggest cue to past problems is asymmetry, due to stress or illness.
∙ Sniffing t-shirts – smelling the armpits to smell the chemicals that comes off the body
o Women can detect t-shirts that were worn by symmetrical men just by sniffing
them, but they can only do this when they’re ovulating. So symmetry is ultimately
important when you’re ovulating. The pill throws this all away. ∙ MHC – major histocompatibility complex. Essentially tells us how related or genetically
similar that person is to you. Detecting relatedness verses non-relatedness (strangers vs.
∙ *Mating females prefer the smell of genetically dissimilar men to her.All this works below
the threshold of awareness.
∙ Pregnant women want men that are strongly similar to her (even family members) She
doesn’t want to be dating her cousin, but she is attracted to the presence of people than
can help her/spend time with her.
o This has been replicated 100% with mice.
∙ These critical decisions are being made below our awareness.
∙ This distinction gets expressed all the way down to the micro level.
∙ Men cross-culturally between 18 and 83 seek physically attractive women. They use an
ideal waste to hip ratio and youth.
o Waste to hip ratio (.7) is a sign of fertility (hour glass shape) – universal signal
men respond to unconsciously, even if they have no intention of making babies.
o There is not a known culture on the planet where they don’t do this.
∙ Caveman logic: Gladiator frog does basically the same thing, but in a different way.
o Male’s job is to create a nest and defend the eggs
o Therefore an ideal mate would be a “tough guy”
o They will not mate with just anyone.
∙ Females do not tend to mate indiscriminately
∙ Nowhere does someone find all people attractive.
∙ There are all kinds of deals that get made in every species.
∙ There’s an underlying puzzle: in our species can our male detect when the female is
ovulating? Is ovulation cryptic among humans?
o Are we able to keep that information private if we want to?
Lecture from November 14 th
Side note Technology has created facial recognition – camera wont flash until person is
• € Sex that invests more in offspring is the slower sex and takes more care of mate.
What would happen with gay men?
• € Less fussy – both partners have 100-1000’s of partners which is what we would predict
• € In contrast, gay women – you find that in general they have the same number of partners
as straight women – which is what we would predict • € Summary being gay doesn’t change anything
• € Some men engage in parenting which slows down their sexual advantage
• € Most men are monogamous
• € In a perfect monogamous system, men and women have equal reproductive rates
· There is no perfect monogamous system its an unnatural system and its very recent
o We look at the world through our lens – monogamy is only 500 years old so it
hasn’t had a huge impact on natural selection.
· 85% of cultures in this would are polygamous “polygamy” (1 man, several women)
• € Typically occurs in SMALL groups
• € BBC News – Mark Ward – suggests that monogamy may have evolved because of
DECEPTION, there is a possibility that serest is concealed in human females.
o Monogamy only persists because females found a way to disguise whether they
are fertile by offering sex anytime, whether or not they are estrus.
o Possible way that monogamy came about
• € Even in monogamous societies, infidelity, divorce, remarriage typically return us
• € Men are much more likely to remarry after divorce than women, and typically remarry
o “Men get the fertile years of more than 1 women.”
• € ***This suggests that women are more selective and choosier about their sexual partners
than men are.
What would happen if sex roles would reverse?
• € If men had a greater parental investment than females
• € Specific implications for Triver’s theory – what it would do to behaviour of males and
o Everything we know about it in the kiwi example should be reverse
o Where can you find this?
Fallarow bird (it goes exactly in the direction we would expect) males
make 90% of the investment, the females lay eggs and give it to the male
and leave. The females are larger, they are more colorful, they are more
competitive for access to the males, females have free time. Sexual
selection is greatly enhanced and forces females to compete for a
diminished pool of available partners.
Investment • € If fathering offspring is the goal, then why don’t male routinely impregnate as many
females as possible and leave?
o Abi-parental investment because it increases chance of survival of the
o If you look at he whole scale and try to predict when males might help it will
depend on the degree of helplessness of the young and the time needed for
Human babies are very fetal (takes years for them to be on their own)
therefore, there is a greater need for bi-parental investment in human than
in other species.
• € What does investment mean?
o For women bodies
o For men resources
This difference affects what desirable trait mean in a partner. There is a
huge difference between what men give and what women give to nurture a
What is desirable?
· In general, guys are looking for good-looking, younger women who are good sex partners
and fertile. Women tend to look for older men with status, wealth and resources.
• € Note: There is a difference between who you are looking for as a sex partner vs. who you
wan tot spend the rest of your life with.
• € Men who think they don’t want to have children is contrary to how their bodies will
guide them. NS programs men to guide them reproduce – circuitry guides preferences.
• € Denying existence of circuitry in the name of free will isn’t a good start.
• € Is a very good sign of reproductive potential – especially in women
• € Women spend millions to reduce signs of age because it’s a signal of lack of
• € Women in their 20’s are the gold-standard
• € There are very specific facial features that are universally perceived as beautiful and
attractive and happen to signal health and reproductive abilities
• € The opposite of these signal parasite infestation
• € Literature suggests that we are all born symmetrical and lose it over age, from stress,
illness, parasitic infestation and by the time we are older we gradually move in the
direction of asymmetry.
· Symmetry reflects present health and past medical record. • € There are faces that are universally beautiful – example: Julia Roberts and Denzel
o Julia Roberts married “one of the ugliest guys”- together they sum to an average
• € Evo psych suggests that women can detect tshirts that were worn by symmetrical men
o à but they can only do this when ovulating
• € MCH (Major histo compatibility complex)-
o Tells you how genetically similar that persona is to you.
o Tells you relatedness vs. no relatedness, stranger vs. family
o **Mating females prefer the smell of dissimilar men
o All the circuitry to make these decisions is below the level of awareness
o Pregnant females prefer men who are strongly SIMILAR
Why: because she needs help (attracted to the presence of people who can
help = close relatives)
o Study has been replicated with mice.
• € Critical importance decisions are being made below our awareness (smell not sight)
• € Study: there is a conflict the distinction in a relationship between two things
Don’t always get both in one package.
o If you have to choose, this distinction gets expressed at the level of
• € In general, men cross-culturally (age 18-83) seek physically attractive women –
o Ideal waist to hip ratio (sign of fertility) .7 – Universal signal men respond
to as a sign of attractiveness even if they have no intention of making children.
Sign of reproductive success.
Gesture men typically make when a women has an ideal wait to hip
ratio. Ganoid fat tells you that person is reproductively viable. – hourglass
There is not a known culture where this doesn’t happen. – they always
prefer hourglass shape, never straight, round etc…
o Awomen’s wait to hip