Steven Crane Compiled Section Handouts. Human Behavioral Biology 2012

Kin selection/inclusive fitness

1. 
   Cooperate with relatives, encourage their reproduction.
   
2. 
   Reciprocal altruism, formalized through game theory with the prisoner's dilemma:
   
   1. 
      
      When to cooperate vs. defect
      

What typically characterizes species that demonstrate reciprocal altruism?
1. "Species that are social, long-lived enough and in sufficiently stable groups so that individuals interact with each other more than once (how else can the reciprocity occur?), smart enough to recognize individuals and, critically, smart enough to try to cheat at the reciprocity when it’s possible to get away with it (i.e., to not reciprocate an altruistic act), and smart enough to spot someone trying to cheat against them." -extended notes
What is Axelrod's famous winning strategy? What does even better under some conditions?

1. 
   Tit for tat. Will lose battles but win wars. Will lose to cheaters, but pairs of TfT will win more than cheaters ever will.
   
2. 
   Better with forgiving tit for tat (less prone to signal errors)
   
3. 
   Pavlov can exploit forgiving tit for tat
   

What are five examples of TfT or interesting elaborations?

1. 
   Vampire bats (TfT)
   
2. 
   Stickleback fish (TfT)
   
3. 
   Gender switching fish who defect if the other defected (TfT)
   
4. 
   Cowardly lions who are good hunters (different domains of contribution)
   
5. 
   Huge naked mole rats plugging up holes (different domains of contribution)
   

Related to kin selection: the greenbeard effect. What is it?

1. 
   Not about recognizing kin, necessarily, but instead just one gene that allows for
   
   1. 
      Recognition of the gene in other individuals
      
   2. 
      Cooperation with other individuals that have that gene Related to cooperation: rock-paper-scissors equilibrium
      

1. Actually restraint from competition. Not true altruism. How does cooperation/altruism start?
1. Founder population cooperates on a basis of kin selection. Then when re-integrated into large population, they keep "winning the war" and cooperation crystalizes outward or non-cooperation is driven extinct.

Pair Bonding and Tournament Species

How do we explain imprinted genes?

1. 
   Father's imprinted genes cause a more "selfish" infant that grows a lot, suckles lots of nutrients, etc. at the expense of the female's future reproductive success. Tournament species males are interested in mating with many females until they get kicked out.
   
   1. 
      What happens when these go unchecked? Choriocarcinoma.
      
   2. 
      Mother's imprinted genes do the opposite. Slow down growth and nutrient uptake. She's equally interested in the success of future progeny as much as this one.
      
      1. 
         What happens when these go unchecked? Egg won't implant
         
   3. 
      Exemplify inter-sexual competition via parent-offspring conflict. Higher in tournament species.
      

How do we explain competitive infanticide?

1. 
   Definitely not for the good of the species!
   
2. 
   When the average tenure of the head male is shorter than the average interbirth interval in females.
   
3. 
   Males operating under individual selection: wipe out other infants so mothers can be impregnated (tie to oxytocin
   

- nursing - fertility suppression - endocrinology foreshadowing), plus less competition for his future offspring.

4. 
   Females coping via individual selection principles: smell of new male causes spontaneous miscarriage because it doesn't make sense to have an offspring that will be killed. Save on pregnancy costs and get pregnant with the new male. Female still has 50% genetic interest in her offspring whether it's old male or new.
   
5. 
   Females coping via kin selection: defending their children up to a point (when would they lay down their life?), also faking pseudo-estrus to fool the new head male into not forcing them to spontaneously miscarry from harassment.
   

What are some further behavioral examples explained well by sociobiology?

1.