Dawkins, Richard (1976). Chapter 10-12, You Scratch my Back, I’ll Ride on Yours
(Pgs.166- 188) and Nice guys finish first (Pgs.202-233). Oxford University Press
Summary by Deekshitha Divyendar, Georgia Devito, Maddie Lipkowitz and Alex Xie
For Dr.Mills Psyc100 Class, Fall 2014
Chapter 10 : You scratch my back, I’ll ride on yours
In the nature, the idea of “you scratch my back, I’ll ride on yours” does not work. If you
place a scenario where “A” has a parasite located in an area where “A” cannot reach and
“B” comes along and helps “A” get rid of the parasite. Then later in the future “B” has the
same problem and goes to “A” in hopes of having the favor returned. However “A” turns
and walks away from “B”. “A” is considered a “Cheater”, an individual who accepts other
individual’s altruism without repaying it back.
Then let’s picture a population where it is comprised of 50% “Suckers”, individuals who
groom indiscriminately, and 50% “Cheaters”. The cheats would start to gain benefits
without cost as the suckers keep grooming the cheats. As time passes the cheats’ genes
would pass on as the suckers die from the parasite. When the population reaches 100%
“Cheaters” that species would start to go into extinction as none of the cheats are
grooming each other and removing the parasite.
However when we add a third type in the equation called “Grudgers”, individuals who
first groom and discriminate anyone who does not return the favor, the Grudgers are
there to weed out the cheats and returns the favor back to anyone that does. So in a
population comprised of 50% “Grudgers” and 50% “Cheaters”, as time passes the
Grudgers would make mental notes on who the Cheaters are and would not groom them
in the future. This then leads to the death of Cheaters by parasites and then the
population would be 100% Grudgers and the species would continue to prosper.
The idea that works in nature and life is “you scratch my back, I’ll scratch yours”, with
the idea of exchanging altruism between each individual you can create a kind of
symbiotic relationship. This idea works in many organism lives in nature. One being the
zebra and oxpecker (a kind of bird). The Zebra provides food to the oxpecker in the form
of ticks and parasites and the oxpecker warns the Zebra of predators in the form of a
warning call.
Another form of altruism is between social insects, such as bees, ants and termites.
These insects have great cooperation with each other and provide numerous altruism to
their queen. This is due to the fact that the female version of the insects are sterile which
means they are not capable in reproduction. Only the queen is able to reproduce more
insects. However the question is why do female worker drones help the queen
reproduce? The answer is that since they are not able to reproduce they help their queen
or mother to reproduce instead. This allows the female worker drones to pass on some
of their genes into the next generation. This is because each baby the queen produces,
the female worker drones share around 50% of their genes with the baby.
There are plenty forms of altruism, another being between ants and fungi. The ants
provide leaves to the fungi to break down which in turn allows the fungi to grow. Then
when the ants get hungry they break pieces of the fungi to consume.
Another form of altruism is between ants and aphids. The ants protect the aphids from
harm, while the aphids provide ants nectar. The ants every go as far as taking the baby
aphids into the ants den and raise them until they mature, then they gently carry them
to the aphids feeding grounds to produce nectar. A way to look at this is that aphids are
the ant’s version of a cow. Where the nectar is their version of milk.
Chapter 12, Nice guys finish first
CONCEPTUAL OUTLINE
A) Game Theory (Prisoner’s Dilemma) Strategies
1. Nice/Good Strategies
Strategies that first pick COOPERATE are considered to be
nice strategies.
a) Tit for Tat Strategy
b) Tit for Two Tats Strategy
2. Nasty Strategies
A nasty strategy is a strategy that DEFECTS before the other
player has defected.
a) Naïve Prober
b) Remorseful Prober
B) Division of Games
1. Zero Sum Games
A game where there could be only one winner. (Soccer)
2. Nonzero Sum Game
A game such as Prisoner’s Dilemma where both players could
be winners.
C) Payoffs
1. Mutual Cooperation (CC)
2. Defection while the other cooperates (DC)
3. Cooperation while the other side defects (CD)
4. Mutual Defection (DD)
SUMMARY
As the worldly saying goes- ‘Nice guys finish last’. And although in evolutionary
terms according to Darwinism, a nice guy would be someone who helps other genes
replicate over his own by incurring personal costs in the process, in which case, nice
guys do indeed finish last, there is also another definition of a nice guy that we need to
consider. This other definition of a nice guy is a nice guy in the Game Theory. Game
Theory is essentially the best decision an individual could take given the strategies that
are at play during the time. It could be easily explained with the help of a Payoff Matrix.
Suppose there are 2 players playing a card game and there are four possible outcomes.
First (REWARD)- Both players COOPERATE and win $300. Second(PUNISHMENT) Both players DEFECT and pay a fine of $10 to the bank. Third
(TEMPTATION/SUCKER’S PAYOFF)- 1st player COOPERATES and 2nd player
DEFECTS leading the second player to win $500 and the first player (SUCKER) pays
$100 to the bank. Fourth (TEMPTATION/SUCKER’S PAYOFF) - 1st player DEFECTS
and 2nd player COOPERATES leading first player to win $500 and second player
(SUCKER) pays $100 to the bank. In fact, the popular ‘Prisoner’s Dilemma’ works in a
similar fashion, where you replace money with jail term.
Therefore, a nice guy in Game Theory is the one who COOPERATES and the bad
guy is the one who DEFECTS. We learn that in the Game Theory, a person who
COOPERATES has an upper hand in comparison to the person who DEFECTS.
Although this theory is extremely simple, it is so hard to understand to a lot of clever
individuals as they think more cunningly whereas they don’t need to. The origins of the
nice guy stems from reciprocal altruism. Note that the nice guy doesn’t always win. In
simple Prisoner’s Dilemma, the best decision for each individual is to always DEFECT.
This is because there is no means of establishing trust between the two individuals.
However, there is another version of the Prisoner’s Dilemma – the repeated Prisoner’s
Dilemma or the ‘Iterated’ Prisoner’s Dilemma. Iterated Prisoner’s Dilemma is
essentially the same thing as simple Prisoner’s Dilemma explained above with the only
difference that it is played multiple number of times between the same players. This
leads to analyzing your opponent’s patterns and there is a means of establishing trust or
mistrust as you can in a way predict your opponent’s move after having played him/her
a few number of times. This repeated game is way more complex than the regular simple
Prisoner’s Dilemma. When the players trust each other, they can succeed at the expense
of the banker rather than at the expense of each other.
Robert Axelrod, in order to test the iterated model, asked experts to submit
strategies; preprogramed rules for action. Fourteen strategies were come up with and
Axelrod added a fifteenth strategy called ‘Random’ which played COOPERATE and
DEFECT randomly. All these strategies were fed into a computer and each strategy was
paired with every other strategy including itself (15x15=225). After 200 moves, the
winnings were totaled up and the winner was declared. Surprisingly, the winning
strategy was the most ingenious and simplest of all – Tit for Tat Strategy. It is the
strategy where COOPERATE is played first and thereafter, whatever is played by the
opponent is repeated. If Tit for Tat is playing against Tit for Tat, both end up
cooperating throughout the game. If Tit for Tat plays Naïve Prober, which is similar to
Tit for Tat except once in a while it plays defect. After the Naïve Prober defects, Tit for
Tat retaliates and imitates defect and Naïve Prober copies Tit for Tat’s move and
cooperates. This leads to a situation where: Both Tit for Tat and Naïve Prober do worse
in comparison than Tit for Tat playing Tit for Tat. Other strategies Tit for Tat is played
against is Remorseful Prober who is similar to Naïve Prober but feels remorse and tries
to correct itself back to cooperate, however, Tit for Tat playing Tit for Tat is still at the
top of the game. Tit for Tat is considered to be a nice strategy; one that is never first to
defect. Tit for Tat is the nice guy.
Now translating this game in terms of evolution, money is replaced by offspring.
In nature, all living beings engage in the Prisoner’s Dilemma and it is proven that
playing nice helps. However, playing too nice doesn’t (Tit for Two Tats). We go back to
the Grudger birds, who help each other in an altruistic way but don’t help the birds that
have refused to help them before. Grudgers dominated the population by passing more
genes to the future generations than Cheats(who took favors and didn’t return them
bringing both of them down- bad guys) and Suckers (who helped others
indiscriminately , and were exploited – too nice). Prisoner’s Dilemma is not a zero sum
game, meaning that both parties can win at the expense of the banker. In evolutionary
terms this translates to the fact that both parties can win by surviving better at the
expense of the nature if they cooperate with each other and help each other. Therefore,
by maintaining the selfish gene at the helm, nice guys can finish first by availing the
advantage of reciprocal altruism and the bad guys are generally driven out of the
environment and become extinct.
However, it is also interesting to note that a strategy works well in a climate
dominated by that strategy. For example: Tit for Tat works well in a climate that is
dominated by Tit for Tats, as all cooperate. Now, Tit for Tat is a robust strategy, which
means that it works well with most of the strategies present in the climate. Therefore, in
a climate filled with diverse strategies, Tit for Tat is your best bet. It is important to note
that Tit for Tat never wins a game, as it never scores more than it’s opponent. It’s benefit
results from a mutually shared high score. This is how living being help each other and
mutually benefit each other to share a high score(pass on to the future the most number
of genes). This goes back to how the strategy is not a zero sum strategy where only one
player needs to win but rather a nonzero sum strategy where both players can enjoy a
position of high score without one player having to be higher than the other. The idea
even applies to many real life modern world scenarios surrounding humans. Consider a
couple getting a divorce. It makes sense for the couple to share the same lawyer instead
of find two separate lawyers to represent each of them as it saves on money. Although it
is a financially better for the couple to share a lawyer, the lawyers don’t represent
couples together and the resulting benefit is enjoyed by the lawyers alone. The hapless
couple is sucked into a zero sum game whereas they could have played a nonzero sum
game by mutually cooperating with each other to reach a common ground without
having to involve lawyers. Another example is that of men involved in a war. Mutual
cooperation with the particular enemy soldiers facing you across no man’s land most
definitely affects your fate and it is greatly better than mutual defection. This situation is
a true Prisoner’s Dilemma. Alternatively, the soldier could choose to mutual defection
(DC) if he is patriotic and he could get away with it. This behavior could also be seen in
fishes that have no gender and switch as they prefer between the two genders. In a fish
couple, if the fish that was supposed to play the female defects, the other fish starts to
defect too and this eventually leads them to break up. It can be seen in vampire bats,
who display a great deal of altruism or favoritism, sharing blood with those bats from
their same cave in comparison to those from outside. Altruism and being nice helps in
carrying forward a living being’s selfish gene in the process of helping other living
beings carry forward their genes as well.
Social behavior
 Social or solidarity ways of life depends on the costs and benefits to the individual
1. Cost/ benefit:
a. Increased competition
b. Availability of resources
c. Attraction of predators
 Patch size refers to how food is distributed
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a. Sociality would be costly for animals with small, scattered patch sizes
b. Sociality is good for animals with large, scattered patch sizes
Sociality in a species
1. Good for sociality
a. Sociality can be used as a defense
b. Scattered but rich patches
2. Bad for sociality
a. Diseases
b. More likely higher predation
c. Eaten more animal prey
Societies are focused around kinship
1. Kin=highly reliable source of aid
a. Biological kinship inhibits lethal violence
 doesn’t include step siblings or spouses
2. Kinship weighs more in situations where fitness is challenged
Reproductive value curve
1. represents age-specific expectation of future off spring
a. Peaks at sexual maturity
Effects of living with non-kin
1. has measurable physiological and health consequences
a. Higher levels of cortisol in kids living with a step parent than a
biological
b. Higher rates of sickness
High reciprocity
1. happens when cost is low and benefit is high
a. Inability to reciprocate causes individuals to shy away from asking for
help
Cheater detection
1. enhances the chances of facial detection
a. People are able to recognize cheaters in advance
b. allows people to minimize altruistic behavior
2. Altruism spreads when withheld from cheaters
How we guard our reputation
1. Non-iterated games results in people being nicer than the game theory
would predict
2. People are nicer when they are being watched
a. Anonymity reduces niceness
In-group bias
1. How we treat people in our group as compared to those we view as part of
another group
2. Alliances for mutual gain were important to reproductive success
a. Such behavior pays off in the form of reproductive fitness
3. In-group and out-group bias becomes more intense when the distinctions
are more obvious
4. We categorized people
a. Race is a misread of a coalition alliance
 Encoding race results from a misfiring of adaptions for detecting
alliances
 Historically most large scale conflicts are based on religion and
ethnicity which can be accounted for as our in-group/ out-group
perception
In the chapter on social behavior the textbook begins with the cost and benefit
relationships in regards to living a social lifestyle. Animals take into account the increase
or decrease in competition (reproductively), the availability of resources, and whether or
not the increased size will be more attractive to predators. Animals will also take into
account the environment and distribution of food, which is called the patch size. With a
small, scattered patch size sociality would be costly for a species; but when the patch size
is large and scattered sociality would help a species. The large, scattered patch size
works well with a social population because they can spilt up to find food and once
found can signal others in the group. Being social is also good in a sense that it can be
used as a weapon of protection. On the other hand diseases, higher predation, and (if
needed) an increase in the amount of prey needed to feed the group. Societies in the
animal kingdom are built around kinship. Kin are thought of as a highly reliable source
of aid. It has been shown that biological kinship inhibits lethal violence, however this
inhibition of violence is not shared with spouses or stepsiblings. The true importance of
kinship comes when fitness of an animal is tested. The effects of living with non-kin
have show high correlation with physiological and health consequences such as high
levels of cortisol and high rates of general illness when children live with no relational
guardians. In lieu of kinship high reciprocity is shown when the benefit outweighs the
cost. Interestingly enough when people fell they are less likely to be able to reciprocate
they will not ask for help. Connected to kinship and reciprocity is the idea of altruism.
Altruism is shown throughout the animal kingdom and has evolved along side cheater
detection. We are programmed to detect certain facial characteristics of cheaters. When
detected we are naturally programmed to withhold acts of altruism from such people. As
a species our level of niceness to others seems to be influenced by the scenario. When
anonymous levels of niceness become reduced and when we are being watched our
niceness increases. Being social creatures we unconsciously create in-group and out
group categories. We treat those that are not in our certain in-group differently than we
do those that are, and the more of a distinction the between the two causes a wider
chasm. An example of in-group bias is race; this is a misfiring of our ancestral adaptions
that detected alliances. In conclusion we are a social species because the benefits
outweigh the costs leading to the occurrence of altruism and reciprocity.
Questions:
1. All of the following are costly to being a social species except…
a. Increased competition
b. Small, scattered patch sizes
c. Higher predation
d. Large, scattered patch sizes
Living with non-kin has no negative effects on a child as compared to one who is living
with kin. False
Tit for Tat Strategy in game theory is a robust strategy. True
Which of the following is not a nasty strategy?
a. Tit for Tat
b. Naïve Prober
c. Remorseful Prober
d. Random Strategy
Altruism can be seen in zebras, bees, ants, fungi, and aphids. True
Which role in a society notes which individuals do not reciprocate and discriminate
against them?
A. Sucker
B. Cheater
C. Grudger
D. Queen
E. Worker