Introduction to Psychology Suzy Scherf Lecture 13: How Do We Interact? Why be Social? Why do...

Introduction to PsychologySuzy Scherf

Lecture 13: How Do We Interact?

Why be Social?Why do Families Fight?

Conflict Resolution

Why be Social?

Why are some organisms social and others are not?

Isn’t is always beneficial for a species to be social?

Why be Social?

Isn’t is always beneficial for a species to be social?

Not Necessarily!

Have to weigh the costs and benefits of being social

Why be Social?

What are the benefits of being social?

1. Can share knowledge about where resources are located

2. If you hang out in groups, you may have more protection from predators

Why be Social?

What are the costs of being social?

1. Have to compete for resources

2. If you hang out in groups, you may be more visible to predators

Why be Social?

Selection favors social habits if the benefits associated with others outweigh the costs!

Even the social nature of a species is likely to be an adaptation designed by natural selection.

Why be Social?

What are the environmental conditions that would encourage a species to be social?

Why be Social?

For example, why are virtually all great apes social except the Orangutan?

Why be Social?

For example, why are virtually all great apes social except the Orangutan?

1. Orangutans live up in trees of rain forests - predators a minimum

2. Orangutans are large-bodied - predators a minimum

Why be Unsocial?

** There is no anti-predator benefit for Orangutans to be social

** Orangutans eat from trees that fruit on different cycles and are hard to find - don’t want to share rare resources

Why be Social?

Some general selection pressures favoring social habits:

1. Patch size - food distribution small, scattered = non-sociallarge, shareable = social

Why be Social?


2. Predators: hunting small, available prey = non-socialhunting large, unavailable prey = social

Why be Social?


3. Common Non-food Resource:

• locations of safety from predators

• grouping to deal with physical forces in the environment

Why be Social?Do gorillas and chimps get an anti-predator benefit and/or have benefit from sharing resource knowledge?

Why be Social?

• Gorillas and chimps have few natural predators

• Gorillas and chimps don’t forage in big groups - food is fairly available

Why be Social?

Protection from each other is the biggest benefit of being social for chimps and gorillas

• Males commit infanticide

• Males fight for dominance and often kill each other

Why be Social?

Protection from individuals within own species is also a selection pressure favoring social habits -

even at the cost of other opposing pressures not to be social

Why be Social?

What may have been some of the selection pressures favoring social habits in our ancestors?

Selection Pressures Favoring SocialHabits in Our Ancestors

1. They inhabited more open, less forested country

• More time on the ground = Increased vulnerability to predators

• More time on the ground = More access to herds for food


2. Having access to grazing herd

• Dietary shift to dependence on meat

• More meat dependence = more collaborative hunting


3. Non-meat food scattered in rich patches

• Sharing knowledge about rich patches of food or water benefits individuals within the group


4. Protection from each other

• Foraging alone vs in small groups

Social Life in the EEA

Small populations in which most of the individuals were related genetically

Communities organized around kinship

Social Life in the EEA

Biological Kinship (even today) fundamentally influences social interactions

WHY?

Because we share genes!

Biological Kinship

Direct vs. Indirect genetic routes to the next generation

• Direct Route = Having own offspring

• Indirect Route = Kin Selection

Biological Kinship

You can pass your own genes down via reproduction but you can also encourage the reproduction fitness of those that you share genes with

However, encouraging the reproductive fitness of someone else may cost you!

Kin Selection

Kin Selection can only work if altruistic traits are selectively aimed at genetically relatives!

Kin Selection

Kin Selection = altruistic genes can spread by benefiting other carriers of the same gene

Altruistic traits = those that may cost you while benefiting someone else

Kin Selection

Kin Selection can be described by a mathematical relationship:

rb > c

r = coefficient of genetic relatedness (0-1)

b = benefit to the recipientc = cost to altruist

Kin Selection Example

(.5)(.25) > (.1)

r = siblings (.50)b = .25 units of fitness (4 acts would

increase the recipient’s reproductive success by 1 offspring)

c = 0.1 units of fitness (10 acts would reduce the altruist’s reproducitve success by 1 offspring

rb > c

Kin Selection Example

(.5)(.25) > (.1)

rb > c

This alturistic trait is likely to be selected for by natural selection.

(.5)(.25) < (1)

This alturistic trait is not likely to be selected for by natural selection.

Kin Selection Example: The White-Fronted Bee

Eater

• When resources scarce (i.e. food, mating opportunities, territory) older siblings will often stay in the nest after sexual maturity to help raise siblings

• Sometimes, parents even recruit grown offspring as helpers by harassing them

But We do Help Folks We’re not Biologically Related to...

Reciprocity - you-scratch-my-back-and-I’ll-scratch-yours


Reciprocity occurs consistently under some specific conditions….

1. Cost of reciprocity have to be small compared to the benefits of reciprocity


Reciprocity occurs consistently under some specific conditions….

2. The altruist and the recipient must regularly exchange roles


Reciprocity under these conditions turns short-term altruism into long-term cooperation!


Reciprocity can only be selected for if cheaters are discriminated against!

Else the cheaters would always win and the altruists would always loose


Reciprocal Altruism can only spread if altruism is withheld from cheaters.

How do we know who the cheaters are without getting burned all the time?

How do we Recognize Cheaters?

1. Recognition of individuals - especially those with whom we regularly interact

2. Tit-for-tat strategy!

Tit-for-Tat Strategy of Cheater Detection

Prisoner’s Dilemma

Your best friend and you have been accused of cheating on an exam. You guys know that you did actually cheat on the exam. You have to meet with the professor separately, but agree before hand to keep silent.


Prisoner’s Dilemma

Your professor has enough evidence to convince the dean that you were cheating to a lesser degree than you actually did.

Tit-for-Tat Strategy of Cheater DetectionPrisoner’s Dilemma

1. If you both remain silent, you will both get a Incomplete in the class.

2. If you both confess you will both get an F in the class.

Tit-for-Tat Strategy of Cheater DetectionPrisoner’s Dilemma

3. If you or your friend remain silent while the other confesses, the one that confesses can finish the course but the other has to leave school.


Your Choice

Your Friend’s Choice

Silent

Silent

Confess

Confess

Both get I

Both get FYour friend leaves school and you finish the course

You leave school and your friend finishes the course

What would you do?


What would you do if you went double-or-nothing?

What would you do if your friend cheated the first time?

What would you do if your friend keep silent the first time?


People tend to use a tit-for-tat strategy:

1. Cooperate on first round

2. On the second round, do what your friend did of the first round


People tend to use a tit-for-tat strategy:

Tit-for-Tat fosters cooperation, but punishes cheaters!

Other Kinds of Social Interaction

What does kin selection theory say about decision-making with respect to helping others?

Decision Making to Help

People are much more likely to help biological relatives than to help unrelated individuals

This is true especially in dire situations and varies with reproductive value!


Age of Target75< 1 yr. 10 18 45

Ten

denc

y to

Hel

p

Highest Reproductive Value


Decisions about helping others appear to be designed to be facultatively dependent on r, b, and c!

Decision Making to Hurt - Aggression

• People kill/abuse/neglect their kin much less frequently than they do non-related individuals.

• Spouses and step-children and are the most likely to be killed or neglected within a household.

Decision Making to Hurt - Aggression

• What about all the aggression within families and among friends?

• More episodes of aggression but also more attempts at reconciliation among members in a relationship

Aggression and Conflict Resolution

• Conflict resolution functions to maintain relationships by undoing social damage

• Conflict resolution reduces aggression in the dominant indiv. and reduces fear in the subordinate indiv.

• Relationships that represent a high social or reproductive value to each other

Which Kinds of Relationships are Worth Maintaining?

• Why is there a lot of conflict and then resolution within a family or a social community?

Why Conflict and Resolution?

• Lots of negotiation that defines and re-defines the relationship (i.e. weaning)

• Ensures the continuation of cooperation among parties with conflicting interests! (i.e. third-party mediation)

Introduction to Psychology Suzy Scherf Lecture 13: How Do We Interact? Why be Social? Why do...

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