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Psychology 485 March 30, 2010 Introduction & Philosophy of Morality Group Living & Cooperation • Altruism • Game Theory Moral Instinct? • Ultimatum game • Fairness and empathy in animals “the difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind” • Darwin, The Descent of Man "Of all the differences between man and the lower animals, the moral sense or conscience is by far the most important" • Darwin, The Descent of Man Some Traditional Answers: • Reason • Experience • Religion/God A newer answer: • Moral Instinct Morality springs from reason Categorical Imperative • Only acts that can be universally permissible (and thus expected) can be taken Morals (or moral problems) excite emotion Emotions cause behaviour • Reason has nothing to do with it How are ethics grounded in the natural world? • Evolution & Biology? • e.g. Westermarck effect Need to avoid naturalistic fallacy • What is in nature is what “ought” to be • e.g. eugenics In psychology, general perspective has been to break morality into stages Successively more sophisticated reasoning • Piaget: 3 stages • Kohlberg: 6 stages Downsides: • More conspicuous to predators • Foraging competition Upsides: • Shared vigilance for predators • Group defense • Cooperation and Reciprocation • Information sharing Does living in a group require a code of ethics? Functional definition: • Acting in a way to reduce individual personal fitness, but increase overall fitness of group Examples: • Alarm calling • Food sharing • Adoption/sharing parenting • Grooming Altruism explained through genetic relatedness • Inclusive fitness “Selfish Gene” • Helping out family members helps your genes get passed on Rescue behaviour in ants Altruism in non-kin Expectation of ‘returning the favour’ Detection of cheaters? • Would behaviour evolve cheating was common? Tit-for-Tat strategy Mathematical approach to multi-agent interaction • Specifies what agents should do to maximize their payoffs against rational agents Nash Equilibrium • Stable solution to game theoretic problems • Evolutionary stable solution (ESS) 2 suspects caught by police • Cooperate (stay silent) • Defect (testify against other guy) Players should always defect Nash equilibrium does not equal globally optimum solution Can cooperation be elicited if game is played multiple times? If total number of trials is known, continue to defect • Should defect on last trial, since no opportunity for other player to “punish” • If both will defect on last trial, should defect on 2nd last… etc. If total number of trials is not known, defection may not be dominant strategy • Tit-for-Tat: Cooperate, then copy Studies show that animals tend to defect, even in iterated problems • Temporal Discounting? Stephens, McLinn & Stevens (2002) • IPD with blue jays • Food held in ‘accumulator’ to reduce discounting • Cooperate in Tit-for-Tat strategy Moral values change with cultural & lifestyle • e.g. smoking, working mothers, divorce, homosexuality Vegetarian lifestyles: • Health vegetarians – don’t eat meat for practical, health reasons • Moral vegetarians – don’t eat meat for ethical reasons More likely to see meat as ‘contaminant’, believe other people should be vegetarians, associate vegetarianism with other virtues (less aggressive) But “instinct” or gut-feelings seem to have control: Moral Dilemma 1a: • A surgeon walks into the hospital as a nurse rushes forward with the following case. “Doctor! An ambulance just pulled in with 5 people in critical condition. Two have a damaged kidney, one a collapsed lung and one a completely ruptured liver. We don’t have time to search for possible organ donors, but a healthy young man just walked in to donate blood and is sitting in the lobby. We can save all five patients if we take the needed organs from this young man. Of course, he won’t survive, but we will save all five patients.” Is it morally permissible for the surgeon to take this young man’s organs? Moral Dilemma 1b: • A train is moving at a speed of 150 mph. All of a sudden, the conductor notices a light on the panel indicating complete brake failure. Straight ahead of him on the track are five hikers, walking with their backs turned, apparently unaware of the train. The conductor notices that the track is about to fork, and another hiker is on the side track. The conductor must make a decision: He can let the train continue on its current course, thereby killing the five hikers, or he can redirect the train onto the side track and thereby kill one hiker, but save five. Is it morally permissible for the conductor to take the side track? Most people: • “no!” to question 1 (organs) • “yes!” to question 2 (trains) Parallel structure, same calculus • What’s the difference? Hints at moral intuition Search for Universal Moral Grammar • Parallel to language Cross-cultural similarities Julie is traveling in France on summer vacation from college with her brother Mark. One night they decide that it would be interesting and fun if they tried making love. Julie was already taking birth-control pills, but Mark uses a condom, too, just to be safe. They both enjoy the sex but decide not to do it again. They keep the night as a special secret, which makes them feel closer to each other. What do you think about that — was it O.K. for them to make love? Haidt (2001) Broken down into 5 main themes: • Harm/Empathy • Fairness/Reciprocity • Community • Authority/Hierarchy • Purity If morality is “built-in”, based on instinct, parts of human morality may have precursors in animal behaviour • Moral building blocks? Focus on 2 dimensions: • Harm/Empathy • Fairness/Reciprocity Rhesus monkeys trained to pull a chain for food reward • Now response leads to another monkey getting shocked (in addition to food) Monkeys will go hungry for days Masserman et al (1964) Rats trained that pressing a lever lowered a styrofoam block Tested with “suspended rat” • All rats worked to lower the other rat Rice & Gainer, 1962 Player 1 is given $100, must offer a split to Player 2 Player 2 can accept or reject offer • If reject, neither player gets any money Rational: Accept anything • But, offers less that 20% are often rejected • Why? Violates principle of ‘fairness’ Chimp version of ultimatum game Jensen, Call & Tomasello (2007) Must work together to pull in food reward Chimps rarely refused offers • Rational response Design problems? “Any animal whatever, endowed with well-marked social instincts, the parental and filial affections begin here included, would inevitably acquire a moral sense or conscience, as soon as its intellectual powers had become as well developed, or nearly as well developed, as in man.” • Darwin, The Descent of Man