1. Evolutionaire psychologie.................................................................................................. 4
1.1 Altruism and Natural Selection .................................................................................... 4
1.1.1 Natural selection and behavior ............................................................................ 4
1.1.2 Altruistic behavior ................................................................................................ 5
1.1.3 Inclusive fitness and kinship (Hamilton, 64) ......................................................... 5
1.1.4 Reciprocal altruism (Trivers, 71) ........................................................................... 7
1.1.5 Cooperation and competition .............................................................................. 7
1.2. Sexual Selection and Sex Differences in Behavior: An evolutionary perspective on
sex differences ................................................................................................................... 7
1.2.1 Sexual selection and parental investment ............................................................ 7
1.2.2 Mating preferences .............................................................................................. 9
1.2.3 Young men: risk, violence and honor ................................................................. 11
1.2.4 Cuckoldry and jealousy ....................................................................................... 12
2. Interaction: Cooperation and Competition ..................................................................... 13
2.1 How does a collective work? ..................................................................................... 13
2.1.2 Mixed motives .................................................................................................... 14
2.1.2 Structure of interdependence ............................................................................ 15
2.2 Beyond Direct Self-Interest: Transformation of Situations ....................................... 16
2.2.1 Interpersonal dispositions .................................................................................. 17
2.2.2 Beliefs regarding other’s behavior...................................................................... 19
2.2.3 Features of the relationship ............................................................................... 21
2.2.4 Social norms ....................................................................................................... 21
3. Aggression ....................................................................................................................... 23
3.1 Theories of aggression ............................................................................................... 23
3.1.1 Biological approaches ......................................................................................... 24
3.1.2 Psychological approaches ................................................................................... 25
3.1.3 Personal and situational variables ...................................................................... 28
3.2 Aggression as a social problem .................................................................................. 31
3.2.1 Intimate partner violence ................................................................................... 31
3.2.2 Sexual aggression ............................................................................................... 32
3.3.3 Bullying in school and workplace........................................................................ 32
3.3 Prevention and intervention ..................................................................................... 33
3.3.1 Catharsis ............................................................................................................. 33
3.3.2 Punishment ......................................................................................................... 33
3.3.3 Incompatible responses ...................................................................................... 33
3.4 Psychopathy .............................................................................................................. 34
1
, 3.4.1 What is psychopathy?......................................................................................... 34
3.4.2 Theories of origin ................................................................................................ 36
3.4.3 Psychopathy and leadership ............................................................................... 37
4. Prosocial Behavior ........................................................................................................... 38
4.1 Helping and altruism.................................................................................................. 38
4.1.1 Altruism vs. egoism ............................................................................................. 39
4.2 Why we don’t help .................................................................................................... 40
4.2.1 Bystander effect ................................................................................................. 40
4.2.2 Other contextual variables ................................................................................. 42
4.3 Why do we help? ....................................................................................................... 42
4.3.1 Cost and benefits of helping ............................................................................... 42
4.3.2 Groups and identity ............................................................................................ 43
4.3.3 Social identity and bystander effect ................................................................... 44
4.3.4 Mood .................................................................................................................. 45
4.4 Issues in researching prosocial behavior ................................................................... 46
4.4.1 Violence and helping .......................................................................................... 46
4.4.2 Gender and helping ............................................................................................ 47
4.4.3 Long-term helping .............................................................................................. 48
4.5 Evolution and Neuroscience ...................................................................................... 50
4.5.1 Evolution, genes and helping .............................................................................. 50
4.5.2 Neuroscience ...................................................................................................... 51
5. Attraction and close relationships - Affiliation ................................................................ 52
5.1 Importance of relationships ...................................................................................... 52
5.1.1 Psychological and physical wellbeing ................................................................. 52
5.1.2 Social support ..................................................................................................... 54
5.1.3 Social exclusion ................................................................................................... 55
5.1.4 Need to belong ................................................................................................... 55
5.1.5 Attachment ......................................................................................................... 56
5.1.6 Interpersonal Attraction ..................................................................................... 57
5.2 Romantic relationships .............................................................................................. 62
5.2.1 Love .................................................................................................................... 62
5.2.2 Satisfaction and stability ..................................................................................... 64
5.2.3 Enhancing relationship functioning .................................................................... 65
5.3 General relationship processes ................................................................................. 66
5.3.1 Types of relationships ......................................................................................... 66
2
, 5.3.2 Disclosure & Responsiveness.............................................................................. 66
5.3.3 Relationship ending ............................................................................................ 67
5.3.4 Growing old together ......................................................................................... 68
6. Emotions .......................................................................................................................... 69
6.1 What is an emotion? ................................................................................................. 69
6.1.1 Pre-cognitive theories......................................................................................... 69
6.1.2 Social – psychological construct ......................................................................... 70
6.2 Why do we have emotions? ...................................................................................... 71
6.2.1 Evolutionary origin.............................................................................................. 71
6.2.2 Signal system ...................................................................................................... 72
6.2.3 Flexibility in behavior .......................................................................................... 72
6.2.4 Information processing ....................................................................................... 73
6.2.5 Regulation and control ....................................................................................... 73
6.3 How are emotions elicited and differentiated? ......................................................... 74
6.3.1 Schachter - Singer ............................................................................................... 74
6.3.2 Wundt's 2 dimensions ........................................................................................ 75
6.3.3 Appraisal theory ................................................................................................. 76
6.3.4 Modern theories ................................................................................................. 77
6.4 Specific response patterns......................................................................................... 79
6.4.1 Face..................................................................................................................... 79
6.4.2 Voice ................................................................................................................... 79
6.4.3 Control and strategic manipulation .................................................................... 80
6.4.4 Physiological changes ......................................................................................... 82
6.4.5 Feelings ............................................................................................................... 82
6.5 Interaction between emotion components............................................................... 84
6.5.1 Proprioceptive feedback ..................................................................................... 84
6.5.2 Emotional contagion ........................................................................................... 85
6.5.3 Consequences of emotion-regulation ................................................................ 86
3
,1. Evolutionaire psychologie
Overzicht:
1. Altruism and Natural Selection: An evolutionary perspective on human nature
a) Natural selection and behavior
b) Altruistic behavior
c) Inclusive fitness and kinship
d) Reciprocal altruism
e) Cooperation and competition
2. Sexual Selection and Sex Differences in Behavior: An evolutionary perspective on sex
differences
a) Sexual selection and parental investment
b) Mating preferences
c) Young men: risk, violence and honor
d) Cuckoldry and jealousy
1.1 Altruism and Natural Selection
1.1.1 Natural selection and behavior
Evolutionary psychology investigates the evolutionary origin of behavior and consequences for
current psychological mechanisms.
Darwin (1859): “The Origin of Species” -> natural selection
Selection in nature occurs because some organisms survive better and reproduce
better in a certain environment
è better fitness (= transferring next-generation genes), grote fitness
zorgt voor grotere kans om genen door te geven
è better adaptation to environment
è Darwin was de eerste die hier een echte theorie voor vormde, gaat in tegen het idee van
eerdere idee van Creationism (religieus, God creëerde de wereld)
è Primary interest: evolution of physical features
vs. Modern Darwinians:
Primary interest: evolution of behavior (e.g., altruistic behavior)
Evolutionary perspective on human nature:
Universal characteristics: These successful characteristics provide such an evolutionary
advantage, that they spread throughout the population and become typical for all mankind
è Explaining why we behave in a certain way, looking for explanations, advantages spread &
become universal
• Bipedalism (mens begint op twee voeten te wandelen, werd
universeel, groot evolutionair voordeel)
• Universal psychological features/characteristics
4
,Vb. Giraf: giraffen met lange en korte nekken, enkel die met
een lange nek kunnen aan de blaadjes bovenaan in de boom.
Lange nek = succesvol gen, deze wordt doorgegeven. Nu
hebben giraffen enkel nog lange nekken. Het uiterlijk verandert
totdat het past bij de omgeving
Darwin focuste meer op het uiterlijke/fysieke, nu meer focus
op de evolutie van gedragingen
1.1.2 Altruistic behavior
= helping others although it may be detrimental to your own fitness
“Helping is part of
Vs. our DNA”
Natural selection = seemingly selfish process
How to explain this? -> Het ontstaan van altruisme s een beetje raar, aangezien evolutie vooral
bepalend is voor je eigen persoonlijke succes, anderen helpen speelt hier niet echt een rol.
-> The universal need to belong = de mogelijke verklaring hiervoor. Je hebt de groep nodig om te
kunnen overleven dus je wil geaccepteerd worden. Is dus eigenlijk wel een zeer adaptieve
eigenschap, je hebt het nodig en is zo geëvolueerd.
Baumeister & Tyce (1990): “social anxiety” as an adaptation to prevent exclusion from the
group
è Angsten zijn adaptief (bv. angst voor slangen, is nodig, anders zou je sterven als je er te dicht
bij in de buurt kwam) & dus ook social anxiety is adaptief, heb je nodig
DEMO: Who would you help? Fellow student? Your brother or sister?
è Wie zou een nier geven aan een klasgenoot? Wie zou een nier geven aan een zus/broer?
è Is een voorbeeld van de Inclusive Fitness theorie. Je zou sneller je sibling helpen dan een
random klasgenoot
1.1.3 Inclusive fitness and kinship (Hamilton, 64)
= your personal reproductive success + the effects you have on the reproduction of your genetic
relatives, weighted by the degree of genetic relatedness
• identical twin: genetic overlap = 100%
• parents - child: 50%
• brother/sister: 50%
• aunt/uncle - niece/nephew: 25%
• cousins: 12.5%
= better fitness (of next generation) by helping (genetic) relatives
è by saving your siblings life, you’re also saving your own genes. By helping your relatives, your
genes survive too. (since your genes are very alike)
è By helping relatives, you have a better fitness.
5
,This implies…
• One takes risks for genetic relatives
• The higher the genetic relatedness, the higher the risk one takes !
► vb. Daly & Wilson, 88
• Children receive less care of step parents than natural parents
• more child abuse by stepfathers (100 x more than natural fathers)
► vb. Burnstein et al., 94
• more help towards genetic relatives in trouble
Het huis staat in brand, wie zou je helpen?
è Meer helpen indien meer genetisch gerelateerd
è Nog een groter effect indien het gaat om een leven/dood situatie!
= het principe van inclusieve fitheid
Helpen in relatie tot leeftijd van de persoon die hulp nodig heeft
è Triviale hulp? (niet zo ernstig)
-> oude mensen en zeer jonge mensen (baby’s) meer helpen
è Ernstige hulp nodig? (leven/dood situatie, bv. huis in brand)
-> jonge mensen meer helpen, hier heb je nog iets aan, die kunnen
zich nog voortplanten, de oude mensen zijn minder belangrijk want die
kunnen zich niet meer voortplanten
Helpen in relatie tot leeftijd van persoon, in een conditie waar de
persoon honger heeft (famine conditions)
è Is meer een lange termijn probleem
è Geen linaire relatie, wel curvelineair, omgekeerde U vorm
è 10-jaar oude kinderen worden het meest geholpen, 10-jarigen zijn
niet te ver van repruductieve leeftijd. Baby’s moeten nog 14jaar leven
alvorens ze kunnen reproduceren, te kleine kans dat ze nog zo lang
overleven in conditie van famine. 10 jarigen zullen makkelijker/sneller
tot aan de reproductieve leeftijd geraken dus het is beter om hun te
helpen, de kans is groter dat ze het halen.
Conclusion:
• Who we help in different situations is predictable from an evolutionary perspective
• Strong evidence for the inclusive fitness theory (deze teste Burnstein adhv scenario’s die
hij bevroeg)
6
,1.1.4 Reciprocal altruism (Trivers, 71)
Why do we help unrelated individuals?
“I help you when you help me”, voor het eerst omschreven door Trivers,
is only possible if:
• the person being helped can be recognized later
• deceivers can be punished: cheaters are excluded (when only receiving help & not
giving help, you get excluded – very difficult to survive)
è only in intelligent species (primates, humans)
è only with acquaintances and small groups / tribes (guarantees reciprocity)
è In the end, helping increases fitness! (= nut van reciprocal altruism)
1.1.5 Cooperation and competition
Evolutionary psychology explains natural selection by
- competition: for limited goods (bv. food, bv. lange nek van giraf)
- cooperative: for common interests
- for relatives (inclusive fitness)
- for acquaintances (reciprocal altruism)
= why ‘helping' became part of our DNA, it increased our own fitness
è These occur together!
bv. Shared parenting:
- Cooperation: both parents are necessary for survival of offspring (bv. birds,
primates, humans) -> beide ouders moeten samenwerken, anders sterven hun
jongen
- Competition: increase own fitness by infidelity (mating with another, happens
frequently, is better for your own survival of genes)
- Infidelity among humans:
Accounts for 10 to 30% of offspring born to stable couples (!)
è Human relationships involve both unselfish love (cooperative) and conflict (competition)
generated by self-interest (ex. infidelity), at the same time.
1.2. Sexual Selection and Sex Differences in Behavior: An evolutionary perspective on sex
differences
1.2.1 Sexual selection and parental investment
Sexual selection = a form of natural selection
= involves the selection of – and different access to – sexual partners
• Intrasexual competition: the winner passes on more genes (male competition, vechten voor
het vrouwtje, de betere genen zullen winnen & kunnen voortplanten -> bv. herten)
• Intersexual competition: choosing a mate based on their preferences (female choice,
between members of the opposite sexes, male peacocks are colorfol because females
preferred the colorful ones, they choose the one they want to mate with)
7
,Parental investment theory (Trivers, 72):
= Sexes differ in terms of time and effort spent in raising offspring (pregnancy, feeding, protecting,…)
• women invest more in raising offspring
• men invest only in their seed
à difference in parental investment results in a variation in
reproduction between the sexes (females reproduce less)
(female record: 69 children/ male record: over a 1000)
à this will result in several sex differences!
Prediction:
The sex that invests less in raising offspring will be less selective in choosing partners and will prefer
having more (sexual) partners
è Undergraduates – What’s the desired number of sexual partners? (Buss & Schmitt (1993)
Women: 1 during the next month / 4 to 5 in their
whole life
Men: 2 during the next month / 8 during the next year
/ on average 18 in their whole life
Men choose more partners: d = .87 (= large effect)
Size of sex differences?
Effect size ‘d’
|d| > .20 = small
|d| > .50 = medium
|d| > .80 = large
vb.
Bv. Lombardo & Deaner
(2018):
Throwing ability: d = 1.98
Even with a very big effect
size, there can still be an
overlap.
The difference within the
sexes is still bigger than the
difference between the sexes!
è Undergraduates – “I’ve noticed you around…I find you very attractive”: (Clark & Hatfield,
1989)
• Would you go out with me tonight? (F: 55% / M: 50%) (responding yes)
• Would you come over to my apartment tonight? (F: 6% / M: 69%) (responding yes)
• Would you go to bed with me tonight? (F: 0% / M: 75%) (responding yes)
o Mannen antwoorden meer ja naarmate de vragen vorderen, itt. vrouwen
o Mannen zijn dus minder selectief bij het kiezen van een seksuele partner
Replication in Austria ~ identical findings (Voracek et al., 2005)
Attitude towards casual sex: men more positive
• Oliver & Hyde (1993): d = .81
• Petersen & Hyde (2010): d = .45 (nog steeds subtatiele differences, maar minder sterk)
8
, è Probability of consenting to sexual intercourse after having known someone for a certain
time (Buss & Schmitt, 1993)
-3 = definitely not
0 = neutral
3 = definitely yes
Women: highly unlikely to have sex after
knowing someone for 1 week
Conclusion:
Men are less selective in choosing partners
DEMO:
What do you think men and women find the most attractive in a potential partner?
• Materially well-off -> vooral vrouwen willen dit, hogere parental investment
• Younger versus older -> mannen kiezen jonger, vrouwen ouder, hogere parental
invenstment te verwachten bij oudere mannen & dit willen vrouwen
• Physically attractive -> vooral mannen willen dit
1.2.2 Mating preferences
Prediction:
men are looking for partner who is young and physically attractive (- sign of fertility)
women are looking for a partner who can provide material support (- good financial prospect)
(Women are more dependent on their partner, they want someone who can provide support)
Confirmed in 37 cultures (Buss, 1989); Replicated in 2011 (Russock)
‘Structural powerlessness hypothesis’: Alternative explanation for the difference
è Eagly & Wood (1999): men are associated with the role of breadwinner / ‘money maker’;
women are financially dependent on their man (gender roles)
è It’s the gender roles that are the reason for the sex differences, they say.
But! If this were true, rich woman would not look for a partner who had good financial prospect,
since they would be able to provide for themselves. But it seems that this is not true.
è When women have a higher income/SES (“money is not an issue”), they place even higher
importance to financial means/SES in men!
(Buss, 1989; Delton et al., 2006; Todosijevic et al., 2003; Wiederman & Allgeier, 1992)
è No support for the ‘Structural powerlessness hypothesis’
9
