11 January 2011
Psych 178 – Lecture 3
The Person as a Machine
Altruism – why does it exist?
• It is not the survival of the self but the survival of the gene pool.
• You would sacrifice yourself to save your offspring if there is more genetic gain than cost in doing so.
Characteristics that reduce survival chances – 2 challenge of classical theory
• Peacock feathers are not in service of individual survival.
Nature Video – Triumph of Life
• One sex often pays a higher price than others in reproduction.
o Females have to bring up the offspring but the males are only involved in the sex act itself.
• Females instinctively make sacrifices to breed. This is built into their genes.
• Some males sacrifice their life so that they can father more offspring with the female. He will die eventually,
so he might as well sacrifice it to increase his chances of passing on his genes.
• Sockeye salmon migrate back to where they were hatched, despite the dangers on the way. Although they
are exhausted, they have to fight for mates.
• Cloning is a way of reproducing without having sex. This means that both the offspring are genetically
identical. It is quick and there is no risk in looking for a mate.
• Some geckos can do this too: the female can lay eggs without needing to mate and they will all be
genetically identical to the mother. However, this is not always the best strategy because of predators and
o If one gecko falls ill, the entire genetically identical population will also get sick.
o Geckos that have sex with others means that the offspring are unique and parasites and disease
cannot spread as easily through this population, even though this method of expansion is half as
• What are the sexual/reproductive advantages of being a male?
o Less investment
o No time out for pregnancy
o Potentially limitless opportunities
• What are the sexual/reproductive advantages of being a female?
o Does not need to compete for mates. Ultimate choice is given to the female. Male has to win
o Female always knows the offspring is theirs
• Disadvantage of being a male?
o Have to compete for mates
o Unsure of parenting
• Disadvantage of being a female?
o Cruel bind of being a mother. She cannot leave her offspring or they might not survive and pass on
her genes. This means she may not survive. More investment. Risk during childbirth.
o Time out during pregnancy
o Less opportunities, fewer potential offspring Experiment 2
• When the death of a child occurs, more people think that the mother will mourn more because she had
more investment and may not be abl