9 - Reciprocity Flashcards
What is reciprocal altruism (reciprocity)?
A behaviour whereby an organism acts in a manner that temporarily reduces its fitness while increasing another organism’s fitness, with the expectation that the other organism will act in a similar manner at a later time.
“I’ll scratch your back if you scratch mine”
Describe three types of reciprocity
Based on this, what is the best ESS?
Mutualism
- Best if both cooperate, worst if both defect
Stag hunt
- Best if both cooperate, worst if opponent defects
Prisoner’s dilemma
- Best if you defect and your opponent cooperates
- Worst if you cooperate and your opponent defects
- Big pay off for cheating
Best ESS: Always defect, cooperating can have costs, both defecting is neutral, you defecting is beneficial
When is an altruist benefiting?
When is a non-altruist benefiting?
With this in mind, how can reciprocity work?
Altruist
- When it encounters another altruist
Non-altruist
- When it encounters an altruist
Reciprocity works when:
- Past interaction influence reward (for cooperation) and punishment for defection
- When there are many opportunities to interact
Low number of bouts are met with ___ bouts in opponent
Low number of bouts are met with low number of bouts in opponent
High number of bouts receives high number of bouts in return
What are 3 main conditions for reciprocity?
- Many opportunities to interact
- Benefit of receiving altruism bigger than cost of donating (or else this would not be selected for)
- Influence of past interactions on reward (for cooperation) and punishment of behaviour (for defection)
What is the purpose of enforcement, coercion, punishment etc. for altruistic groups?
Punishment used with defecting behaviours sometimes to prevent free loading,
other times to keep a hierarchy where altruism is based around dominant animals (coercion)
- Dominant meerkats evicting pregnant subordinates to prevent them from breeding, meerkats help dominant mating couple to raise offspring
Is reciprocity altruism?
Not really, more like delayed mutualism.
Altruism involves cost to your own fitness, which may or may not happen with reciprocity.
True or false?
There are lots of reciprocity in nature
false
Not very much empirical examples of this
True or false?
In reciprocity, you have to be paid off for your cost of donating more than you initially donated
Why?
If the delayed benefit of helping is not paid back more (or at least the same value), this won’t be selected for.
If you look at relatedness of individuals in groups and you see that individuals help each other, is it kin selection or reciprocity?
Often hard to say, as non-kin might be raised near each other.
Does it fill criteria for reciprocity?
- Many opportunities to interact
- Benefit>cost of donating
- Past interactions drive behaviour (reward/punishment)
See if there’s difference between kin/non-kin and proportion of altruistic activities
How can the benefit of donating resources outweigh the costs?
If you are doing well, and you donate, the effect might not be very big on you, but it may potentially save the recipient from death.
Later, they might help you when you need it, giving you a much bigger benefit than what you have up previously.
Monkey A grooms monkey B.
Monkey C doesn’t groom monkey D
When the call of monkey A or monkey C is played, how does B or D respond?
How is this different for kin/non-kin?
- B helps (interchange)
- D doesn’t help
Kin: no interchange
Non-kin: interchange observed
Unrelated monkeys showed reciprocal interchange, but related monkeys didn’t.
True or false? Most examples of reciprocity are very cheap (in terms of fitness costs).
True
Many times reciprocity benefits both the actor and the receiver, or the act is neutral for the actor.
What is an example of coercion for reciprocity in humans?
Eyes or flowers next to honour payment box.
People more likely to put money in honour box if the eyes are there.
