Intro & Predictions: Sean, Billy, Rivers, Alex S. don't worry about the formulas! Study 1: Alex K., Clove, Josh, Dominic don't worry about the stats, i.e., skip Tables 2 and 3, just focus on Tables 1 and 4 Study 2: Katherine, Tianran, MarLa, Kate General Discussion: Robert, Perryn, Angel, Jen

…if a law is to have moral force, i.e., to be the basis of an obligation, it must carry with it absolute necessity… Immanuel Kant (1785) Fundamental Principles of the Metaphysics of Morals

Kurzban et al: Hamilton vs. Kant: pitting adaptations for altruism against adaptations for moral judgment. EHB Dilemma: Parent can either kill one of its offspring, which will allow five others to live or it can do nothing, in which case five of its offspring will die. Hamilton's (1964) theory of kin selection predicts what? Consequentialist means what? Kant predicts what? How are humans and animals thought to be different in this regard? Trolley Problem Siblings vs. strangers: what does Hamilton predict? What does it mean to say that rule-based moral strictures such as do not kill are heuristics caused (in the ultimate sense) by altruism systems shaped by kin selection or reciprocity?

Fig. 1. Two models of decision- making in moral dilemmas. In moral dilemmas, there is a tension between maximizing inclusive fitness, the greater good, and adhering to moral rules such as do not kill. In one model (panel A), evolutionary processes leading to altruism, such as kin selection or reciprocity, cause moral systems which implement simple heuristics for welfare, and these mechanisms push individuals to adhere to moral rules. In another model (panel B), moral cognition pushes behavior toward adherence to simple rules, but altruism systems counteract moral cognition, pulling behavior toward maximizing aggregate welfare. What does altruism mean here?

Trolley Dilemma – Footbridge Version (Strangers) Imagine that one day you are all walking near some trolley tracks. You are on a footbridge over the tracks. One person walks over and stands next to you. He is wearing a large, heavy backpack. Suddenly, a trolley is quickly approaching. You see that five other people are standing on the tracks. The only way to save them is to push a heavy object in front of the trolley. The only available heavy object is the man with the backpack (you are not heavy enough). There is not enough time to take off the backpack, and the people on the track are too far away to hear if you yell a warning. So, you have only two choices. If you push the man onto the tracks, then the trolley will be slowed and the five other people will be unharmed. You are forced to decide whether to push the man in front of the trolley, killing him, or to do nothing, allowing the five other people to die.

Trolley Dilemma – Switch Version (Brothers) Imagine that one day you are walking near some trolley tracks with six of your brothers. Suddenly, a trolley is quickly approaching. You see that five of your brothers are standing on the tracks in the trolleys path. However, you are standing next to a switch that will divert the trolley onto a side track. Your sixth brother is standing on the side track, wearing a heavy backpack. If you switch the trolley, the trolley will be slowed when it hits your brother with the backpack, and the five brothers on the main track will be unharmed. There is not enough time for your brother to take off the backpack, and the people on the track are too far away to hear if you yell a warning. So, you have only two choices. If you pull the switch, then the trolley will be slowed and the five brothers on the main track will be unharmed. You are forced to decide whether to pull the switch, killing your brother on the side track, or to do nothing, allowing the five other brothers to die.

Counterweight Dilemma (Strangers) Imagine one day you are out, and you see three people trying out a new past-time, in which they use ropes to ascend from valley floors onto a bridge. You are on a bridge along with one of these three people, who has already climbed up. This person, who is wearing a very heavy backpack, is on one side of the bridge, looking into the distance. Suddenly, you see that the valley is about to be consumed by a flash flood. You see that the two other people are still on the floor of the valley, directly in the path of the flood waters, and they will die if the water hits them. You notice that a safety rope is still attached to them, and the other end is firmly attached to the man with the backpack. Because of the extra weight of the backpack, you realize that if you push him off the bridge, he and the pack will act as a counterweight, and the two people below will be lifted above the level of the water. However, the fall will cause him to hit a large outcropping of sharp rocks on that side of the bride, and he will certainly die. So, you have only two choices. If you push the man with the backpack off of the side of the bridge, the other two will be pulled above the water and will be able to make it onto the bridge unharmed. You are forced to decide whether to push the man with the backpack off the bridge, killing him, or do nothing, allowing the other two people to die.

Windstorm Dilemma (Strangers) Imagine that you are bird-watching in one of your favorite parks. You see that three men have brought a ladder to climb high up in the trees. Two of them are in one tree about 50 yards away, and the third is nearby where you are standing. Suddenly, a fierce wind begins to blow and everyone starts to lose their grip. If the men dont climb down the ladder soon, then they will fall from the branches and will break at least a few bones (although they will survive). The trees are too tall to climb down without a ladder, and the man by himself nearby begins to climb down the ladder he recently climbed up. You see that you can carry the ladder from where it is to rescue your other two men, but there isnt enough time to get everyone out of the trees. So, you yell up to the man on the ladder to get off so that you can move the ladder, but he continues to climb down. So, to help the other two, you will have to shake the man off the ladder so that you can move it, and he will fall to the ground. You are forced to make a decision. You can do nothing, in which case the man will finish climbing down safely but the other two will suffer injuries. Or, you can shake the man off the ladder causing him to fall and suffer injury, and take the ladder to the other tree, in which case the two men will safely climb down.

Footbridge Dilemma – push 1 to save 2 Push to save Brothers Strangers Would you push? 39% **15% Is it wrong to push? 83% 87% Is it wrong not to push? 61% 44% How wrong is pushing? 5.1 *5.9 How wrong is not pushing? Want someone else to push? 57% **22%

Counterweight Dilemma – push 1 to save 2 Push to save Brothers Strangers Would you push? 40% *21% Is it wrong to push? 82% 86% Is it wrong not to push? 57% 43% How wrong is pushing? How wrong is not pushing? Want someone else to push? 51% *35%

How is the theory of Kurzban et al similar to Haidts?