Causal Reasoning

Drawing and testing cause-effect inferences

CAUSAL CONTROVERSIES

Do “earbuds” cause hearing loss?Is marijuana a “gateway” drug?Does pornography cause an increase in sexual assaults and rapes?Is intelligence hereditary?Is the U.S. government actually responsible for 9/11?What makes people gay, nature or nurture? Does sex education increase teen promiscuity?Do violent cartoon shows make children more aggressive or violent?Does drug interdiction reduce drug demand, or merely drive up the price of drugs?Do police use racial profiling to decide which motorists to pull over?Does the “three strikes law” deter criminals?

Did hurricane Katrina cause an increase in teen smoking?

Teenagers were more likely to smoke cigarettes if they or their family members were affected by Hurricanes Katrina or Rita.A study by the University of Texas Health Science Center surveyed more than 5,100 middle school and high school students 6-9 months after the hurricane.Almost 38 percent of students who had a family member hurt or killed in the 2005 hurricanes also reported that they now were smoking. In comparison, 13 percent who did not endure a death or injury in the family said they smoked.

Does Poverty Cause Crime?

Direct theories– Poverty makes crime pay; illegal activity is the only

way to succeed

Indirect theories– Poverty creates unstable communities– Unemployment creates frustration and despair

Bursik, R. J., Jr., & Grasmick, H. G. (1993). Economic deprivation and neighborhood crime rates, 1960-1980. Law and Society Review, 27, 263-268. Pp. 263-268

Who was responsible for the terrorist attack on the World Trade Center?

September 14, 2001 Jerry Falwell blamed gays and feminists for the terrorist attack on World Trade Center – "I really believe that the pagans, and the

abortionists, and the feminists, and the gays and the lesbians who are actively trying to make that an alternative lifestyle, the ACLU, People For the American Way, all of them who have tried to secularize America. I point the finger in their face and say 'you helped this happen.'"

– NOTE: he subsequently issued a formal apology for his remarks

Is MTV responsible for teens’ imitating Johnny Knoxville? 13 year old Jason Lind poured gasoline on his legs and set them on fire at a friend’s house after watching the “human barbecue” segment of “Jackass”, in which Knoxville donned a flame retardant suit, strapped steaks to his body, and rolled around on a grill to cook them. Another boy also set himself on fire after watching a different episode in which Knoxville, again wearing a fire retardant suit, was set ablaze under the supervision of a pyrotechnics expert.

McLawsuit: Is McDonalds to blame for childhood obesity? U.S. District Judge Robert Sweet dismissed a lawsuit that blamed the McDonald's Corp. fast-food chain for obesity in children.The said the plaintiffs, including a 14-year-old girl who stands 4-foot-10 and weighs 170 pounds, failed to show that customers were unaware that eating too many Big Macs, Chicken McNuggets and Egg McMuffins could be unhealthy. Or are Oreos the real

culprit? (A similar lawsuit was filed against Kraft foods)

CAUSAL REASONING

definition: one condition or event (the “antecedent”) contributes to or brings about another condition or event (the “consequent”).

– example: studying hard (antecedent) leads to good grades (consequent)– example: passive smoke causes lung cancer in nonsmokers

causal relationships are inferred, not directly observed– One can observe that B follows A, but not that B is caused by A.– An eye witness might see an assailant shoot a victim, but a coroner would

still have to determine the cause of death

a cause must precede its effect– Does TV violence cause kids to be violent, or are kids who are predisposed

toward violence drawn to watch violent TV shows?

Everyday cause-effect reasoningMost people have a good, common sense understanding of causation:

– “If I turn on the burner, the water will boil.”– “Turning the key starts my car.”– “When I exercise, I sweat.”

Common sense understandings of causation only go so far.– People often makes erroneous cause-effect inferences

• example: Superbowl Sunday and claims of increased spouse abuse

• example: superstitions, like Ground Hog Day• example: “lucky” lottery strategies• example: internal attributions for success, external

attributions for failure

Types of Causal Reasoningpartial or contributory cause

– example: driver inattention and a car crash on a freeway– example: coral reefs are declining due to global warming,

water pollution, and human contactnecessary cause: a condition that must be present in order for the effect to occur

– example: a college degree is a prerequisite for certain jobs– example: to be eligible for social security benefits one must

be a certain age.sufficient cause: a condition capable of bringing about the effect in and of itself

– example: a blood alcohol level > .08 is sufficient for a DUI conviction

– example: having unprotected sex one time is sufficient for contracting HIV

necessary versus sufficient: the distinction– A necessary condition for the occurrence of an effect is a

state of affairs without which the effect cannot occur, while a sufficient condition is a state of affairs that guarantees the effect will happen.

MORE TYPES OFCAUSAL REASONING

sole cause (both necessary and sufficient)– extremely rare in public, social controversies– beware of arguers who use “scapegoating” by pinning all of society’s problems

on a single cause• example: recent lawsuits alleging McDonald’s was the sole cause of a

person’s obesity• example: global warming isn’t the sole cause of the decline of coral reefs• example: As a condition of the Versailles treaty, Germany was required

to accept sole responsibility for causing World War I. effect-to-cause reasoning (a form of “sign” reasoning)

– looking at effects or symptoms and inferring back to their cause• example: You have a fever, so you may have an infection.• example: All the flags are flying at half mast, so it must be due to a

national tragedy.• example: Jake slammed the door when he came in so he’s probably in a

bad mood.

MORE TYPES OF CAUSAL REASONING

reciprocal causation: two things are both causes and effects of each other

– example: stuttering and shyness– example: the United States’ policy toward Mexico and Mexico’s policy

toward the U.S.– example: couples’ conflicts “I read the paper because you never stop

talking.” “I talk because you won’t stop reading the paper.”

causal “chain” or multi-step causation– Will Viagra help save endangered species? (Associated Press, December

26, 2002)– Does media reporting about famous people who commit suicide produce

“imitation” suicides? (New England Journal of Medicine, September 11, 1986)

– 1% increase in unemployment “causes” 10,000 fatalities (Annual Review of Public Health, 1996, 17:449-65. )

ERRORS IN CAUSAL REASONING

confusing correlation with causation

– example: ice cream sales and drownings

– example: chewing tobacco and playing in the major leagues.

“post hoc” fallacy (post hoc ergo proptor hoc)

– example: superstitions based on coincidence

alternative causation– example: Was the recent economic

recession caused by Clinton, Bush, or Bin Laden?

MORE ERRORS INCAUSAL REASONING

oversimplification or reductionism: reducing a complex problem to a single, simple cause

– example: the decline of the family unit is responsible for all of society’s woes (poor school performance, gang violence, drug and alcohol abuse, etc.)

– example: illegal immigrants are to blame for all of California’s economic problems

associations in advertising: equating and associating products with effects

– linking products with favorable images and lifestyles.• example: Beer = Fun, Good Times

– buying a product doesn’t confer happiness, sexiness, friendships, etc.

• example: wearing a particular fragrance doesn’t guarantee sexual attraction, allure, etc.

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TESTS OF CAUSAL REASONING

is the cause necessary to produce the effect?– Is it necessary to smoke marijuana to be cool?– Are computer skills a must in today’s job market?– Does everyone need a cell phone?

is the cause sufficient to produce the effect?– Is having a “cool ride” sufficient for getting dates?– If someone is religious, does it guarantee she/he is

honest?– Does “being in love” ensure that a couple will be happy

together when married?

MORE TESTS OF CAUSAL REASONING

Are there cumulative (additional, contributory) causes?

– example: Urban density, plus unemployment, plus poverty lead to crime.

– example: The collapse of the dot.com industry, plus Sept. 11, plus the Enron scandal all damaged the economy.

Are there alternative causal explanations?– example: Can “backward masked” song lyrics make someone

commit suicide?– example: What was the cause of the school shootings in Littleton,

Colorado? Are there countervailing causes? Would other factors or circumstances prevent the effect from occurring?

– example: a person’s computer keeps freezing up, so the person suspects a virus. However, the person recently updated her/his anti-virus software.

– example: an arguer claims that pornography is linked to sexual assaults, but evidence shows that Sweden--a country with lots of porn--has low rape and sexual assault rates.