Chapter 10

Cooperation can ___

occur in many ways among animals

One way to study cooperation in lab

experimental procedures that involve 2 animals taking on roles to solve a problem

What happens in the cooperation experiment after the problem is solved?

Both animals get rewards

What did Melis and Tomasello do?

examined cooperation in chimpanzees

Experiment done by Melis and Tomasello:

If both tasks were completed, grapes would drop down and be avaiable from both the front and back sides of the apparatus to reward both chimpanzees.

Result of Melis and Tomasello

regardless of whether the chimp handed both tools or only one tool to its partner, they both received rewards.

Did the chimpanzees know what tools to hand their partner?

They gave their partner the correct tool more often than expected by CHANCE

Joshua Plotnik experiment

Elephant pulling rope to get food learned a social coordination task

What did the elephants from Plotniks experiment learn?

to wait for their partner then pull the rope to get food

What was the result of the plotnik experiment?

Elephants were cooperating to get food, if they weren’t, they wouldn’t wait for their partner

What was seen in the Plotnik experiment?

When cooperation would have yielded no reward, elephants did not cooperate

Animals that are not genetic relatives →

Cooperate with each other in many contexts

Cooperation is

Outcome where 2 or more interacting individuals recieve a net benefit from their joint actions

What is an example of cooperation?

Jointly hunting pray may provide each of 2 hunters with food even though there are costs

To cooperate means

behave in such a way to make the benefits that could be obtained from joint action possible, even though they may not necessarily be achieved

Did social insects show cooperative behavior?

Yes

4 paths to the evolution and maintenance of cooperation

• kin selection

• group selection

• reciprocity

• byproduct mutualism

What did the 4 paths to the evolution and maintenance of cooperation lead to?

Cooperative behavior

Reciprocal altruism

individuals benefited from exchanging acts of cooperative and altruistic behavior

Example of reciprocal altruism

Individual A helping individual B pay for food, this cost is made up later when B helps A

NS favor reciprocal altruism when

Individuals that live in groups interact with the sae partners and when individuals recognize in the future those who had helped them in the past

What is a positive in reciprocal altruism?

it facilitates long-term partnerships with those who help one another

How does reciprocal altruis, evolve?

Game theory

What is game theory

Mathematical tool that is used when the payoff that an indivdual recieves for undertaking an action depends on what behaviors others adopt

What is considered payoff in game theory?

food, mating opportunities, etc

Payoffs

indirect proxies for fitness

Evolution of cooperation is

best understood using a mathematical game called preisoners dilemma

What is prisoners dilemma

2 prisoners in different interrogation rooms either cooperate or defect

Defecting during prisoners dillemma means

tell the authorities that the other suspect is guilty

Cooperation in prisoners dilemma means

stay quiet and not betray the other suspect

What happens if both prisoners are quiet

1 year in jail

What happens if both prisoners tell

3 years

What happens if one prisoner tells and one is quiet

one that tells is free, quiet gets 5 years

What happens if both prisoners cooperate

Both recieve a reward for mutual cooperation (R)

What happens if both prisoners don’t cooperate

each recieves a punishment for mutual defection (P)

If one suspect defects and the other cooperates

The cooperating suspect recieves a pay off of T, temptation to cheat which is 0 years in jail

If one suspect cooperates and the other defects

The defecting indivividual recieves 2, suckers payoff which is 5 year sin jail

Order of payoffs from high to low

T > R > P > S

What should both suspects have done in the prisoners dilemma?

They should have both defected

Why should both prisoners have cooperated?

Mutual cooperation provides all parties with a higher payoff than mutual defection

What happened in the repeated prisoners dilemma game?

If-then rules were created. If she cooperates, I will cooperate; otherwise I will defect

Axelrod and Hamilton searched for ____ to the repeated prisoners dilemma

evolutionary stable strategy (ESS)

What is the ESS in the repeated prisoners dilemma game?

It is a strategy such that if all members of a population adopt it, no mutant strategy can invade

What is needed for a strategy to be evolutionarily stable?

The payoff must be greater than the payoff to any mutant strategy

What was the ESS for the prisoners dilemma game?

A reciprocity-based strategy called tit for tat that relied on the

Tit for tat strategy

Individual cooperates on the initial encounter with a partner and copies their partners previous mood. After this, they operate on a if-then rule.

What is the if-then rule?

If my partner cooperates, then I cooperate, If my partner defects, I defect.

TFT reciprocates acts of _____ and acts of ____

Cooperation, defection

TFT strategy’s success characteristics

• niceness

• retalation

• forgiving

Niceness in regards to TFT

player using TFT is never the first to defect, she initially cooperates with a new partner and cooperates as long as her partner cooperates

Relatiation in regards to TFT

Individual playing TFT immediately defects on a defecting partner since she copies her partners previous move, if her partner defects, she defects

Forgiving in regards to TFT

TFT instructs players to do what their partner did on the last move

Predator Inspection

Pairs of guppies break away from their group → approach dangerous predator

In predator inspection, guppies ___

approach the predator in a coordinated fashion to collect information about the predator

How do the guppies pass along information?

Guppy 1 is better off if guppy 2 takes all the risks and passes down information it recieves to guppy 1 and vice versa

What would happen if both fish opt to wait for the other to inspect the predatory?

Would be worse off that inspecting as a pair

What is failing to inspect or lagging equated to?

Cheating

T > R

more dangerous to be leading an inspection than lagging behind

R > P

inspection occurs in many species

P > S

that single fish suffer very high rates of predation

What would happen if none of the guppies inspected prey?

dangerous for all group members → no one obtains information on danger levels

What’s the most dangerous situatio for a single fish

Being the lone inspector in a group

What species use TFT when inspecting?

guppies and sticklebacks

Fish that inspect predators appear to use a strategy that is

• Nice

• Retaliatory

• Forgiving

“Nice” in terms of fish that inspect predators

each starts off inspecting at about the same point in time

“retaliatory” in terms of fish that inspect predators

as an inspector ceases inspection if her partner stops

“Forgiving” in terms of fish that inspect predators

if inspector A’s partner has cheated but resumes inspection, A resumes inspection at well

Cooperators do better when pair with other ___

cooperators

defectors do better when paired with ___

cooperators

all individuals should prefer to associate with ___

cooperators

Inspectors remember the ____ and _____ of their co-inspectors

identity and behavior

When a group size is small:

fish chooses fish that was cooperative previously

Transmitter fish →

Inspects predators

Transmitter fish → Inspects predators =

decrease foraging as they approached

Reciever fish =

Didn’t see or inspect

Reciever fish = Didn’t see or inspect =

After seeing transmitter inspect

Reciever fish = Didn’t see or inspect = After seeing transmitter inspect =

Decrease foraging

Roosts of vampire bats

largely female and low coefficient of relatedness

Vampire bats have blood meal and

regurgitate to others, more likely to those they shared meals with

Look at whether relatedness, reciprocity, or both →

explain evolution and maintenance of sharing blood meals

If hungry bat approaches a satiated bat →

much likely to get a regurgitated blood meal if she has fed the satiated bat in the past

Genetic relatives are more likely to

swap blood meals with one another than with other individuals

Reciprocity is

the practice of exchanging things with others for mutual benefit

Wilkinson’s created an

index of opportunity for reciprocity

Wilson’s index of opportunity for reciprocity consists of

3 lines of evidence that reciprocity is important in sharing blood meals

Wilson’s index of opportunity for reciprocity #1

probability of future interaction between group members in nest = high

Wilson’s index of opportunity for reciprocity #2

blood meals provide a large, life-saving benefit for recipients

Wilson’s index of opportunity for reciprocity #3

Vampire bats recognize one another

Probability of future interaction between group members in a nest is high as required by

TFT models

blood meals provide a large, life-saving benefit for recipients because

cost of giving up some blood is LOW to the donor

Vampire bats recognizing one another allows for

reciprocal exchange

Vampire bats are more likely to give blood to those who have

donated blood to them in the past

Reciprocity and Food Sharing in Vampire Bats uses

reciprocal altruistic strategy

Neurobiology of human cooperation

Neuroeconomics

Neuroeconomic

research effort between economists and neurobiologists who specialize in brain science

neuroeconomics involves subjects ___

making an economic decision while monitoring brain activity patterns by fMRI or PET

Example of neuroeconomics - females in repeated prisoners dilemma

In the females repeated prisoners dilemma, the highest monetary ($3) reward was recieved by ___

individuals who cheated when their partner cooperated

In the females repeated prisoners dilemma, players said that they felt best about recieving the $2 reward from _____

mutual cooperation and they often cooperated