Evolution & Rationality

Evolution & Rationality Intro to Psych 3/4/2014

Evolution & Rationality Where mental life comes from • Morality • Consciousness • Our decisions • Our judgments

Evolution & Rationality • The “Astonishing Hypothesis” • Theorizes that all of the parts of our mental life come from a “material, physical brain” • A foundational idea of modern psychology developed by Francis Crick But what is the ORIGIN of mental life?

Evolution & Rationality • Think about it this way: • You’re walking down a beach and you stub your toe on a rock • You wonder, “Where did this rock come from?”, but you know the answer won’t be interesting because it’s just a boring rock • But what if you stubbed your toe on a watch? • The answer to “Where did this watch come from?”is probably WAY more interesting • “It came here as an accident”………………AND? • But why do you want to hear the story so bad? • Because a watch is an interesting and complex thing. You want to know its ORIGIN

Evolution & Rationality • The Human Eye vs A Camera • How are they alike? • They both have lenses that bend light to create an image • Eye: Retina • Camera: Film • They can both focus • Eye: muscles that control focus • Camera: part that controls the amount of light coming in • An eye & a camera are a lot alike • A camera was BUILT by intelligent beings to fulfill a purpose • But an eye is so much more complicated than a camera

Evolution & Rationality • Eye vs Camera • An eye is more complex and detailed than a camera will ever be • But an eye is biological, not man-made • Some suggest this complexity in the biological world shows that a high power, a designer, smarter than any human, must have created these intricate, physical things

Evolution & Rationality GOD

Evolution & Rationality • The argument that God is the creator of the biological world is a perfectly logical explanation for where these complex objects come from • It’s compatible with Scripture and religious beliefs • The point also stands on its own • If you find a complicated object, you assume it didn’t just show up out of thin air • You assume it was created by an intelligent being • This view is often called “creationism”

Evolution & Rationality • Problems with the Creationism argument • It pushes back the argument • If it was created by an intelligent being, then where did that intelligent being come from?? • This is a big issue from a psychology viewpoint • We ask “How did creatures come to be on the earth with the ability to reason and plan and do things?” • The creationist answer is “Another creature with those same abilities made us” • This isn’t necessarily a wrong answer, but it is an unsatisfying answer • You immediately want an explanation on where that OTHER creature comes from

Evolution & Rationality • There has always been evidence for evolution • Example: the eyeball • It didn’t just happen all of a sudden • Has parallels with other existing animals across human & biological history • Fossils! • Some fossils show evidence of earlier versions of body parts we now have • Vestigial Structures • Parts of the human body that don’t serve a purpose, but we have them anyway

Evolution & Rationality Some veins Tonsils A fish that could walk on land Spleen Appendix Your tailbone

Evolution & Rationality • Evidence for Evolution • Parallels with other animals, especially from a psychology view • A human brain is different from a rat, cat, monkey • But you also see similarities in structure and plan • This could be because of evolution • Poor Design • Sometimes, things just don’t work so well • Your eye: has a blind spot because of nerve wiring • Male urinary system: the urethra goes through the prostate instead of around it • This leads to many physical issues later in life • Now you have to argue these flaws are actually good things, or that God is incompetent or mean

Evolution & Rationality • Creationsim: for a long time, the only argument around • 100 – 150 years ago it was what everyone believed because it was a good argument from a design perspective • Darwin changed all of that • Darwin showed how you can get these complicated biological structures through a completely physical process • Some argue the theory of natural selection is the most important idea in the sciences. Period.

Evolution & Rationality • Natural Selection • Variation • Creates different degrees of survival and reproduction that gets passed on from generation to generation • These different degrees become “adaptations” • Example: Camouflage • Before Darwin: Intelligent creator crafted animals to be able to hide from their prey • After Darwin: Animals that were better able to hide lived longer, reproduced more. • Elaborate camouflage evolved over thousands or millions of years

Evolution & Rationality Why are we talking about evolution in Psych class?? Two ideas that relate to psychology: • Darwin: biological forms evolve through a purely physical process • The mind is the product of purely physical things and physical events These together force us to think that we are no less than an eyeball, than camouflage That our minds work only for the purpose of survival and reproduction

Evolution & Rationality • How to apply evolutionary theory to Psychology • 2 Misconceptions we need to remember • If we’re being biological about this, everybody must then run around thinking “I want to spread my genes!” WRONG! A cockroach doesn’trun around thinking “I’m doing this to help survive and reproduce and spread my genes!” The things that make the cockroach do what it does are different from its own mental states

Evolution & Rationality • Why do we eat? “Not one man in a billion when taking his dinner ever thinks of utility. He eats because the food tastes good and makes him want more. If you asked him why you should want to eat more of what tastes like that, instead of revering you as a philosopher, he will probably laugh as you for a fool.” - William James

Evolution & Rationality • Common Sense Answer! • Why are you eating? • Because I’m hungry • Because I love this food • Because it’s dinnertime • Not Common Sense Answer • Why are you eating? • Because I must sustain my body so as to spread my genes in the future.

Evolution & Rationality • These two ideas of why we eat are not alternative • They are different levels of explanation • Evolutionary explanation: eat to sustain our bodies to survive & reproduce • Psychological explanation: eat because I am hungry • Another way to look at it: • Why do people protect their children? • What do you think? (Remember our earlier lectures…)

Evolution & Rationality • Why do people protect their children? Why feed them, clothe them, protect them? • Evolutionary example: Animals who don’t protect their offspring don’t last over evolutionary time. We protect them because they have our awesome genes • Psychological explanation: Because I love my children • The psychological explanation is deeper, more meaningful. It has emotion and feeling

Evolution & Rationality • 2nd Misconception we have to remember • Natural selection assumes that everything is adaptive WRONG! • Natural selection distinguishes between adaptations and accidents • Example: Back pain • Why do you/will you suffer back pain? How does back pain help you survive and reproduce? • It doesn’t • Back pain is a accident of how our backs are shaped • More examples: hiccups, self-pity, bloating after you eat • These don’t have an evolutionary purpose. They are just accidents our body does. • Also true for psychology!

Evolution & Rationality • Psychological accidents • Things that interest or fascinate us in our everyday lives • 3 Main Preoccupations of humans: • Television, Pornography, Chocolate • Why do you like pornography? • “Because my ancestors who liked pornography reproduced more than those who didn’t”?? • NOPE • Your interest in pornography is an accident of evolution

Evolution & Rationality • Assume you are a heterosexual male • You have evolved to be attracted to women • You want to have sex with women because that is the first step to having children • Having children is good from an evolutionary view

Evolution & Rationality • Modern world has created images to substitute for a real woman • Instead of going out and meeting a real woman, you stay home and surf the web • If this happens to everyone, eventually this evolutionary adaption ends • No one mates anymore! • So pornography is not part of evolution, it is an accident

Evolution & Rationality • Why do you like chocolate bars? • Because your ancestors on the savannah who like chocolate bars reproduced more than those who didn’t? • NOPE! • We have evolved a taste for sweet things! • Back in the day of our ancestors, sweet things in the natural environment were good for us (Fruits) • Modern world has created more sweet things, like chocolate • They’re not so good for us, but we eat them anyway

Evolution & Rationality • What is an evolutionary adaptation and what isn’t? • Color vision • An adaptation: gives us advantages in seeing and making visual distinctions • Fear of snakes • An adaptation: our ancestors who weren’t afraid didn’t reproduce as much as those who are afraid • Maybe they were all killed by snakes because they weren’t afraid! • Liking chocolate & NASCAR • Accidents: these are recent creations that evolution couldn’t anticipate

Evolution & Rationality • But what about those things that are harder to figure out? • Music • Everywhere in the world, people like music • Is this an adaptation or an accident? • Language • There is more than one language in the world • Adaptation or accident? • Visual art? Fiction? Stories? • What do we think?

Evolution & Rationality • Evolutionary Psychology • Some people don’t think evolution has any place in psychology • Dualism: reject the idea the mental life is the product of your brain. Brain and mind have nothing to do wit each other. Therefore, evolution is irrelevant • Another rejection: the mind isn’t ruled by the same physical laws as the rest of the physical world • Another rejection!: The mind is physical, but all of the instincts and parts of human nature might exist for animals but not for people. Those things are culturally learned, not biological. • More rejection!: Ok, the mind does contain instincts. But we can study those by studying people. How could evolution tell us anything interesting???

Evolution & Rationality • Evolution & Psychology • What can evolution tell us about psychology? • It can tell us what can be innate and what can’t • It can tell us what’s built in and what’s not • Is there a part of the brain just for writing? For playing chess? • Not according to evolution there’s not • It can help us see and understand human differences, both individual and group • Group differences can be found through evolution • Why are children different than adults? • What does evolutionary theory say about sex differences? Why we like men? Why we like women?

Evolution & Rationality • Evolution & Morning Sickness in Pregnancy • Early in a pregnancy, women often get morning sickness • Nausea, throwing up, etc • Generally thought to be because of excess hormones in a woman’s body • But what if morning sickness is NOT an accident of evolution? • What if it has an actual biological purpose? • Margie Profet: morning sickness is a warning for pregnant women; they get sick toward the kinds of foods that can harm their fetus

Evolution & Rationality • Evolution & Morning Sickness • Predictions: • The time in which a woman gets morning sickness should be the time in which the fetus is most vulnerable • The types of foods to avoid are those that were most deadly to a developing fetus during the periods where humans evolved • Important! Women don’t develop a sickness toward alcohol, but we know it to be harmful to the fetus • Why? Alcohol wasn’t around during our evolutionary history, so we haven’t developed a system to protect ourselves from it • Morning sickness is a sign of a healthy protection going on for the fetus

Evolution & Rationality • Rationality! • Humans have built in capabilities to help us think rationally • Framing Effects • Ex: the US is preparing for an outbreak of a disease that will kill 600 people • There are 2 programs: • Program A: 2oo people will be saved • Program B: 1/3 chance everyone lives, 2/3 chance no one is saved • Who would choose Program A? Program B?

Evolution & Rationality • Most people pick Program A • But what if we say it a different way? • Program A: 400 people will die • Program B: 1/3 no one dies, 2/3 chance everyone dies • Is it harder to pick? Does it sound different? Make you feel different about making a choice? • When flipped like this, most pick Program B • This is the “Framing Effect” • You respond differently to a situation depending on how the options are framed

Evolution & Rationality • The Endowment Effect • I show you a chocolate bar and ask you “How much will you give me for this chocolate bar?” • You offer $2 for the chocolate bar • OR • I hand you a chocolate bar and ask “How much will you SELL me this chocolate bar for?” • You say $2.50

Evolution & Rationality • Why more? • Once you own something, to you the value increases. It’s still the same chocolate bar, but now you’re the owner • When I ask how much will YOU give me, it’s a game. How much will you pay for something • But when I ask how much for me to take it from you, you treat it as a loss. I buy it from you, you lose the chocolate bar • A loss is more valuable

Evolution & Rationality • Availability Bias • What is your risk of being eaten by a shark? • Most people overestimate this • Why? Because shark attacks are widely reported when they happen. You remember them happening and think then that they happen more often than they really do

Evolution & Rationality • What is the risk of being killed by potato salad? • One in 55,000 people die of food poisoning • Potato salad is 1,000 times more dangerous than a shark attack • We get it wrong because we don’t think “OMG, big news story! Someone died from potato salad!” • We tend to overestimate the chance of being killed because of dramatic effect

Evolution & Rationality • Confirmation Bias • You’re in a jury for a custody case • You have to give either the mother or father sole custody • One parent has average income, average health, average working hours, relatively stable social life, good relationship with the child • Other parent has above average income, minor health problems, lots of work travel, active social life, close relationship with the child • Who would you give custody to?

Evolution & Rationality • Parent A? Parent B? • Another jury is asked “Who would you DENY custody to?” • That jury will also say Parent B • When you’re asked to AWARD someone, you think “What is a sign that someone is a good parent?” • When you’re asked to DENY someone, you think “Where is a cue someone is a bad parent?” • The bad parent aspects of Parent B then jump out • When we have a hypothesis, we look for confirmation

Evolution & Rationality