How to criticize a theory                     Tutorial Week 4 - Application of Theories                                  B...
What do we know until now?Connection between the lectures
Lave & March model:                                              Charles A. Lave     James G. March                       ...
Hempel & Oppenheim model:      Explanans   General Law (L1)                  Antecedent Condition (C1)    Explanandum   Si...
Hempel & Oppenheim model:     Sentences used                                                      2    Speculate      to e...
Hempel & Oppenheim model:              Explanans            General Law (L1)                                    Antecedent...
Formal Logic: How to test it? 1   Star test       Find the distributed letters and underline them:         Immediately aft...
ClassworkConnection of the models (from Logic)
The case of Social Identity       In Lecture 4 with the case social identity theory, we       extracted from a text an exp...
Example from last tutorial            Ceausescu’s ban on abortion was designed to            achieve one of his major aims...
Any premise can be translatedinto a wff        A boost to the population (B) strengthens a country (S)        A ban on abo...
Explanations (syllogisms) aretestable                            Star test                           All B* is S          ...
Connection of two explanations:Deriving laws.  A boost to the population (B) strengthens a country (S) *(Imp. Assump.)*  A...
4 cases: Your turn   Government agents sardonically known as the Menstrual Police regularly rounded up women in their work...
Empirical ContentCondition 3: The explanans must have empirical content
Empirical content  Our theories must be testable. It must be possible to derive at least one testablestatement from the th...
How much empirical content?                            We want a lot of empirical content    The empirical content of a st...
Empirical content of implicationsWhich of the following statements have a higher empirical content? A      If a person is ...
Let’s recall implications from logic.Operator 4: Implication Symbol:        ⊃ (horseshoe) or → Read:          “if p then q...
When is a disjunction false?        A   If a person is frustrated or hurt, then she will be aggressiveOperator 2: Disjunct...
When is a conjunction false?        B   If a person is frustrated and hurt, then she will be aggressiveOperator 3: Conjunc...
Empirical content of implications (2) Which of the following statements have a higher empirical content? C       If a pers...
When is a disjunction false?        C    If a person is frustrated, then she will be aggressive or sadOperator 2: Disjunct...
When is a conjunction false?       D     If a person is frustrated, then she will be aggressive and sadOperator 3: Conjunc...
In sum:              The empirical content of a statement is the higher the more                     possible states there...
Rational Choice Theory
The theory of rational action:This is a good example of a wrong theory     What do we do when, after testing a     theory,...
The theory of rational action:This is a good example of a wrong theory    A core assumption in RCT is that individuals max...
People have preferences             RCT assumes agents have preferences  Can we test this? Does this implication has empir...
Preferences are hard to test        Think: What if I gave you the 1000 euros and ask          you to donate them right awa...
So, are we assuming non-empiricalimplications?              RCT assumes other things about preferencesCompleteness: for an...
GAmE ThEOry              i              n              t              r              o
stability               learning                        expectations       Selfish                     strategies          ...
Strategic           HISTORY                        Borel (1938)Interaction Theory    Applications aux                     ...
StraTegiC   StraTegiC   StraTegiC   eXtenSivEStraTegiC   eXtenSivE   StraTegiC   StraTegiCeXtenSivE   StraTegiC   eXtenSiv...
Battle of Sexes         Battle of Sexes  They want different things, but   can’t live without the other...                ...
ThiS is a seQueNTial        GAME                      B     (3 , 2)                        B                              ...
Solution Concepts   Dominance                     IDSDS                    Nash Eq.                    pure               ...
Strictly Dominant Strategy        No matter what others        do, you will ALWAYS          use this strategy      Strictl...
P     Q       R               RA   2,7   2,0     2,2        B    3,2B   7,0   1,1     3,2                             P   ...
HOW               possible?                   Common Knowledge       Is            thisI know that you know, that I know, ...
Nash Equilibrium NO unilateralincentives to change    my action...                         BEST                       RESP...
B     S                   B    3,2   1,1                    S   0,0   2,3                If you choose BB    B    3,2     ...
N       B     S                    E    B   3,2   1,1    S   0,0   2,3
PrObleMs M U L T I P L I CI T YSoLutiOn            refinements
SubgameBackward Induction            Perfect                            Equilibrium Start at the END       B    (3 , 2) an...
Prospect TheoryA famous experiment                      Amos Tversky   Daniel Kahnemann                       1937-1996   ...
Condition 1:  Imagine that the US is preparing for the outbreak of an unusual Asian disease, whichis expected to kill 600 ...
Condition 1: Answer    A   If program A is adopted, 200 people will be saved        If program B is adopted, there is a on...
Condition 2:  Imagine that the US is preparing for the outbreak of an unusual Asian disease, whichis expected to kill 600 ...
Condition 2: Answer    C   If program C is adopted, 400 people will die        If program D is adopted, there is a one-thi...
Explanations  The decision problems are identical. Still, the different framing (save lives vs. loosethem) of the effects ...
Currently, is there something better?  A theory (good model), according to Lave and March, should be fertile, simple andsu...
Upcoming SlideShare
Loading in …5
×

T4 Slides

303 views

Published on

Slides Tutorial 4. Course: Application of Theories

Published in: Health & Medicine
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
303
On SlideShare
0
From Embeds
0
Number of Embeds
6
Actions
Shares
0
Downloads
3
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

T4 Slides

  1. 1. How to criticize a theory Tutorial Week 4 - Application of Theories Block A 2012/2013Andreas FlacheManu Muñoz-Herrera http://manumunozh.wix.com/apptheories
  2. 2. What do we know until now?Connection between the lectures
  3. 3. Lave & March model: Charles A. Lave James G. March 4 Steps Observe Speculate Deduce Ask result of are implications Facts other results unknown process empirically correct?Phenomenon Process Implications Modify
  4. 4. Hempel & Oppenheim model: Explanans General Law (L1) Antecedent Condition (C1) Explanandum Singular Statement (E)
  5. 5. Hempel & Oppenheim model: Sentences used 2 Speculate to explain E. Explanans General Law (L1) process (model) Antecedent Condition (C1) Other resultsExplanandum Singular Statement (E) 3 Deduce Phenomenon to be explained 1 Observe
  6. 6. Hempel & Oppenheim model: Explanans General Law (L1) Antecedent Condition (C1) Explanandum Singular Statement (E) This is not enough: Conditions of adequacy. 1 Explanandum follows logically from the explanans Explanans must contain general laws and conditions (any kind?) (what 2 else?) 3 Explanans must have empirical content 4 ???
  7. 7. Formal Logic: How to test it? 1 Star test Find the distributed letters and underline them: Immediately after all Anywhere after no or Star the distributed letters in the premises and the non-distributed in the conclusions If all capital letters are stared exactly once and there is exactly one star on the right hand side - VALID 2 Venn Diagrams Color the areas that do not belong to the premises Mark with an x the are in which some is present in the premises If the conclusion is observed by drawing the premises - VALID
  8. 8. ClassworkConnection of the models (from Logic)
  9. 9. The case of Social Identity In Lecture 4 with the case social identity theory, we extracted from a text an explanation and criticized it by testing its validity Rewrite the arguments verbally Translate your arguments into wff’s Come up with a conclusion that is valid (include implicit assumptions if necessary)
  10. 10. Example from last tutorial Ceausescu’s ban on abortion was designed to achieve one of his major aims: to rapidly strengthen Romania by boosting its population A boost to the population (B) strengthens a country (S) *(Imp. Assump.)* A ban on abortion (A) gives a boost to the population of a country (B) Therefore, a ban on abortion (A) strengthens a country (S)
  11. 11. Any premise can be translatedinto a wff A boost to the population (B) strengthens a country (S) A ban on abortion (A) gives a boost to the population of a country (B) Therefore, a ban on abortion (A) strengthens a country (S) All B is Sall boosts to the population (B) are country strengtheners (S) All A is Ball bans on abortion (A) are population boosters (B) -----------------Therefore, all bans on abortion (A) are country strengtheners (S) All A is SHypothetical Syllogism: A implies B, B implies S,then A implies A.
  12. 12. Explanations (syllogisms) aretestable Star test All B* is S All A* is B ? ----------------- All B is S All A is S* All A is B ----------------- Venn Diagram All A is S A B S
  13. 13. Connection of two explanations:Deriving laws. A boost to the population (B) strengthens a country (S) *(Imp. Assump.)* A ban on abortion (A) gives a boost to the population of a country (B) Therefore, a ban on abortion (A) strengthens a country (S) A ban on abortion (B) strengthens a country (S) In Romania, the dictator Ceausescu, made a ban on abortion (B) ----------------------------------------------------------------------------------------------- In Romania, the dictator Ceausescu, strengthened his country (S) Modus Ponens: If B implies S, and I observe B, then I should observe S A ban on abortion (B) strengthens a country (S) In Romania, the dictator Ceausescu, issued a law (l) that banned abortion (B) ----------------------------------------------------------------------------------------------- In Romania, the dictator Ceausescu, issued a law (l) that strengthened the country (S)
  14. 14. 4 cases: Your turn Government agents sardonically known as the Menstrual Police regularly rounded up women in their work places to administer pregnancy tests: If a woman repeatedly failed to conceive, she was forced to pay a steep “celibacy tax”. On Christmas day of 1989 crime was at its peak in the United States... experts were predicting darker scenarios. The evidence linking increased punishment with lower crime rates is very strong. Harsh prison terms have been shown to act as both deterrent (for the would-be criminals on the street) and prophylactic (for the would-be criminals who are already locked up). Researchers found that in the instances where the woman was denied an abortion, she often resented her baby and failed to provide it with good home... The researchers found that these children were more likely to become criminals. (for the solution you could generalize this example from MORE LIKELY to ALL and focus it in the case of unwanted children)
  15. 15. Empirical ContentCondition 3: The explanans must have empirical content
  16. 16. Empirical content Our theories must be testable. It must be possible to derive at least one testablestatement from the theory The most straightforward way to make a theory testable is to find a way to measurethe variables in its premises (i.e., X and Y in “all X is Y”) and investigate whether thereis the proposed relationship. This would mean that you directly test the assumptions of the theory. BUT... Social scientific theories often include concepts which are very difficult to measure.For two reasons: The concept is not defined properly. The concept is latent in the sense that it cannot be observed directly.
  17. 17. How much empirical content? We want a lot of empirical content The empirical content of a statement is the higher the more possible states there are which would falsify the statement.Minimal Maximalempirical empirical content Empirical content scale contentstatements All bachelors are James is a statements which are not married vegetarian and which arealways true eat stakes always falseTautological Contradictory Statements should have high informational content (not maximal)
  18. 18. Empirical content of implicationsWhich of the following statements have a higher empirical content? A If a person is frustrated or hurt, then she will be aggressive B If a person is frustrated and hurt, then she will be aggressive The empirical content of a statement is the higher the more possible states there are which would falsify the statement. We need to study under which conditions the statements are false.
  19. 19. Let’s recall implications from logic.Operator 4: Implication Symbol: ⊃ (horseshoe) or → Read: “if p then q” p q p⊃q 1 1 1 1 0 0 The implication of p and q is false 0 1 1 only if p is true and q is false 0 0 1 A If a person is frustrated or hurt, then she will be aggressive B If a person is frustrated and hurt, then she will be aggressive A and B are implications: statements which are false if the if-part is true and the then-part is false.
  20. 20. When is a disjunction false? A If a person is frustrated or hurt, then she will be aggressiveOperator 2: Disjunction Symbol: ⋁ (vee) or || or + Read: “or” p q p⋁q 1 1 1 The disjunction of p and q is 1 0 1 false if both p and q are false 0 1 1 0 0 0 There are three possible states where the if-part is true
  21. 21. When is a conjunction false? B If a person is frustrated and hurt, then she will be aggressiveOperator 3: Conjunction Symbol: ⋅ (dot) or & or ⋀ Read: “and” p q p⋅q 1 1 1 The conjunction of p and q is 1 0 0 true if both p and q are true 0 1 0 0 0 0 There is only one possible state where the if-part is true
  22. 22. Empirical content of implications (2) Which of the following statements have a higher empirical content? C If a person is frustrated, then she will be aggressive or sad D If a person is frustrated, then she will be aggressive and sad C and D are implications: statements which are false if the if-part is true and the then-part is false.
  23. 23. When is a disjunction false? C If a person is frustrated, then she will be aggressive or sadOperator 2: Disjunction Symbol: ⋁ (vee) or || or + Read: “or” p q p⋁q 1 1 1 1 0 1 The disjunction of p and q is 0 1 1 false if both p and q are false 0 0 0 There is one possible state where the then-part is false
  24. 24. When is a conjunction false? D If a person is frustrated, then she will be aggressive and sadOperator 3: Conjunction Symbol: ⋅ (dot) or & or ⋀ Read: “and” p q p⋅q 1 1 1 1 0 0 The conjunction of p and q is 0 1 0 true if both p and q are true 0 0 0 There is are three possible state where the then-part is false
  25. 25. In sum: The empirical content of a statement is the higher the more possible states there are which would falsify the statement. Implications are false if the if-part is true and the then-part is false More possible states More possible states when the if-part when the then-part contains a disjunction contains a conjunction than a conjunction than a disjunction The empirical content of a statement is the higher when the if-part contains a disjunction and the then-part contains a conjunction.
  26. 26. Rational Choice Theory
  27. 27. The theory of rational action:This is a good example of a wrong theory What do we do when, after testing a theory, we find it is wrong? Do we discard it? Do we fix it?
  28. 28. The theory of rational action:This is a good example of a wrong theory A core assumption in RCT is that individuals maximize utility What is maximize? What is utility? Unless something is said about it, the concepts are not properly defined There are other implicit assumptions!
  29. 29. People have preferences RCT assumes agents have preferences Can we test this? Does this implication has empirical content? Think: If you had enough money would you donate 1000 euros help a poor hospital in Asia? Yes No
  30. 30. Preferences are hard to test Think: What if I gave you the 1000 euros and ask you to donate them right away. Would you answer the same? Yes No People lie! Even if they don’t want to... Even to themselves
  31. 31. So, are we assuming non-empiricalimplications? RCT assumes other things about preferencesCompleteness: for any two lotteries, either A≼B, A=B, or A≽BTransitivity: if A≽B and B≽C, then A≽CContinuity: if A≼B≼C, then there is a probability p between 0 and 1, such thatthe lottery pA + (1-p)C is equally preferred to B.Interdependence: if A=B, then pA + (1-p)X= pB + (1-p)X With this, preferences (latent variables) are not observable, but choices are: people choose what they prefer
  32. 32. GAmE ThEOry i n t r o
  33. 33. stability learning expectations Selfish strategies players dominance Nash signaling Distrustpayoffs simultaneous Rational common knowledgetypes Equilibrium information preferences subgame matrix tree sequential repetition games backward induction
  34. 34. Strategic HISTORY Borel (1938)Interaction Theory Applications aux jeux des Hazard von Neumann - Morgenstern (1944) Theory of Games and Economic Behavior John Nash (1950) Equilibrium points in n-person games
  35. 35. StraTegiC StraTegiC StraTegiC eXtenSivEStraTegiC eXtenSivE StraTegiC StraTegiCeXtenSivE StraTegiC eXtenSivE StraTegiC GamesStraTegiC eXtenSivE StraTegiC eXtenSivEStraTegiC eXtenSivE StraTegiC eXtenSivEStraTegiC eXtenSivE StraTegiC eXtenSivEStraTegiC eXtenSivE StraTegiC eXtenSivE
  36. 36. Battle of Sexes Battle of Sexes They want different things, but can’t live without the other... B S B 3,2 1,1 S 0,0 2,3 oneSIMULTANEOUS STRATEGIC this is a game shot
  37. 37. ThiS is a seQueNTial GAME B (3 , 2) B S (1 , 1) Players B (0 , 0) Timing S Available Actions S (2 , 3) Payoffs Rules & Consequences
  38. 38. Solution Concepts Dominance IDSDS Nash Eq. pure mixed ? Backward Backward Induction Induction
  39. 39. Strictly Dominant Strategy No matter what others do, you will ALWAYS use this strategy Strictly Dominated Strategy No matter what others do, you will NEVER use this strategyDOMiNANcE (solvable games)
  40. 40. P Q R RA 2,7 2,0 2,2 B 3,2B 7,0 1,1 3,2 P RC 4,1 0,4 1,3 B 7,0 3,2 IDSDS P Q R P RA 2,7 2,0 2,2 A 2,7 2,2B 7,0 1,1 3,2 B 7,0 3,2
  41. 41. HOW possible? Common Knowledge Is thisI know that you know, that I know, that you know, that I know, that you know, that I know, that you know, that I know, that you know,that I know, that you know, that I know, that you know, that I know, I KNOW I KNOW that you know, that I know, that you know, that I know, that youknow, that I know, that you know, that I know, that you know, that I know, that you know, that I know, that you know, that I know, that you know, that I know, that you know, that I know, that you know,that I know, that you know, that I know, that you know, that I know, that you know, that I know, that you know, that I know, that youknow, that I know, that you know, that I know, that you know, that I know, that you know, that I know, that you know, that I know, that you know, that I know, that you know, that we are both... RaTiONaL
  42. 42. Nash Equilibrium NO unilateralincentives to change my action... BEST RESPONSE
  43. 43. B S B 3,2 1,1 S 0,0 2,3 If you choose BB B 3,2 S 1,1 I will choose B B B 3,2 S 1,1S 0,0 2,3 If you choose S S 0,0 2,3 I will choose S B S B 3,2 1,1 S 0,0 2,3
  44. 44. N B S E B 3,2 1,1 S 0,0 2,3
  45. 45. PrObleMs M U L T I P L I CI T YSoLutiOn refinements
  46. 46. SubgameBackward Induction Perfect Equilibrium Start at the END B (3 , 2) and move to the BEGINNING B S (1 , 1) B (0 , 0) S S (2 , 3)
  47. 47. Prospect TheoryA famous experiment Amos Tversky Daniel Kahnemann 1937-1996 1934 Nobel Prize 2002
  48. 48. Condition 1: Imagine that the US is preparing for the outbreak of an unusual Asian disease, whichis expected to kill 600 people. Two alternative programs to combat the disease havebeen proposed. Assume that the exact scientific estimates of the consequences of theprogram are as follows: A If program A is adopted, 200 people will be saved If program B is adopted, there is a one-third probability B that 600 people will be saved and a two-third probability that no people will be saved Which of the two programs would you favor?
  49. 49. Condition 1: Answer A If program A is adopted, 200 people will be saved If program B is adopted, there is a one-third probability B that 600 people will be saved and a two-third probability that no people will be saved 72% of the subjects chose A (N=152) WHY?
  50. 50. Condition 2: Imagine that the US is preparing for the outbreak of an unusual Asian disease, whichis expected to kill 600 people. Two alternative programs to combat the disease havebeen proposed. Assume that the exact scientific estimates of the consequences of theprogram are as follows: C If program C is adopted, 400 people will die If program D is adopted, there is a one-third probability D that nobody will die and a two-third probability that 600 people will die Which of the two programs would you favor?
  51. 51. Condition 2: Answer C If program C is adopted, 400 people will die If program D is adopted, there is a one-third probability D that nobody will die and a two-third probability that 600 people will die 78% of the subjects chose D (N=155) WHY?
  52. 52. Explanations The decision problems are identical. Still, the different framing (save lives vs. loosethem) of the effects leads to different decisions Kahnemann and Tversky concluded that there is more risk seeking in the secondversion of the problem than there is risk aversion in the first. The framing effect Kahnemann and Tversky demonstrated contradicts the idea thathumans form decisions based on utility maximization. Their results contradict the assumption of completeness - the theory of rational choice is wrong According to the fourth condition of adequacy, explanations which assume utility maximization are not adequate What do we do when, after testing a theory, we find it is wrong? Do we discard it? Do we fix it?
  53. 53. Currently, is there something better? A theory (good model), according to Lave and March, should be fertile, simple andsurprising. As long as we don’t have a better theory, we will have to elaborate the theory ofrational choice Different decision rules (bounded rationality) Social preferences (fairness) Include further assumptions about the perceptions of risk So, we fix it!

×