Monday, March 26, 2012

classical conditioning and placebo effects

Classical conditioning is a form of learning or physiological change. It is based on forming an association between a stimulus and a response. The association is remembered and affects future similar experiences. Some physiological responses to stimuli are unconditioned: they happen naturally and involuntarily, like blinking, flinching, or the salivation response to the taste or odor of food. Other physiological responses are conditioned: for example, a dog can be conditioned to salivate when a bell is rung because the dog has been taught to associate the bell with food (Pavlov's famous experiment). Dogs injected with morphine begin to salivate and can be conditioned to salivate from any injection, whether with morphine or not.

Relief from pain is often attributed to the placebo effect when no active pain-killer has been administered and the patient reports that the pain has lessened. A more accurate description in some such cases, however, might be that the patient has learned to associate pain reduction with pushing a button that releases morphine or with getting a morphine injection. I know from experience that self-monitored morphine injection devices are designed to prevent an unsafe amount of morphine from being taken. The patient may push the button and feel relief but after a certain amount of morphine has been released, pushing the button does not release morphine despite what the patient might think. People who have been injected with saline solution but think they are getting morphine may feel relief from pain because they are conditioned to expect relief after the injection.

Conditioning and associative learning--along with owner or practitioner expectation and self-deception--might explain why some animals appear to get relief from reiki, homeopathy, or acupuncture. A woman who does reiki on horses wrote me: "Animals have no preconceived ideas about Reiki; no expectations about a treatment. There is no placebo effect with animals." Those who think animals can't respond to placebos should consider that what is sometimes called the placebo effect is actually a conditioned response to a stimulus and it is a well-known fact that animals respond to conditioning. Conditioning does not have to be done consciously, nor does it have to involve acts like clapping or ringing a bell. Nor does it have to involve belief. The rituals a vet or pet owner goes through with an animal when it is injured or ill can have a conditioning effect.

Conditioning can involve much more than obvious factors like getting an injection, taking a pill, or being touched where it hurts. Conditioning can involve the theater of the medical setting and medical rituals, including the medical uniforms worn, medical jargon spoken, and medical gadgetry used. These conditions affect the patient's expectation of relief from the treatment, as does the manner of the healer. Patient expectation, it turns out, plays a significant role in the effectiveness of many kinds of treatment. Classical conditioning is "hypothesized to be the primary triggering mechanism for the placebo effect ... which must be learned before it can manifest itself...." (Bausell 2007: 131). When conditioning is combined with desire and motivation for relief, the placebo effect is boosted for both active and inert substances.

A common misunderstanding regarding placebos is that a placebo must be an inert substance that tricks the patient into thinking he's been given an active substance. Many people think that the placebo effect is "all in the head," but that is no more true than that people's physiological and behavioral responses to what they think is alcohol or a drug are only in their head. People can be conditioned to respond physiologically and behaviorally "to placebos through repeated administrations of active drugs" (Bausell 2007: 132) and to hypnosis through learned expectation.

Antonella Pollo et al. demonstrated that placebos can help people with serious pain and Martina Amanzio et al. (2001) demonstrated that "at least part of the physiological basis for the placebo effect is opioid in nature." That is, we can be conditioned to release such chemical substances as endorphins, catecholamines, cortisol, and adrenaline. One reason, perhaps, that people report pain relief from both acupuncture and sham acupuncture is that both are placebos that stimulate the opioid system.

Donald D. Price, an expert on pain, has demonstrated that conditioning and expectation significantly affect the experience of pain and pain reduction. R. Barker Bausell speculates that since complementary and alternative medicine (CAM) practitioners' greatest asset is their nourishment of hope, "such therapies may be engendering nothing more than the expectation that they will reduce pain by elaborate explanations, promises, and ceremonies" (2007: 149). He also notes that the analgesics prescribed by our physicians receive a boost in efficacy based on our past experience and expectations. Many advocates of energy medicine mistake the effects of classical conditioning, expectation of relief that leads to reduction of anxiety and stress, and beliefs about the effectiveness of energy medicine as being consequences of manipulating a mythical subtle energy.

In her book, Women Aren't Supposed to Fly: The Memoirs of a Female Flight Surgeon, Dr. Harriet Hall tells the story of a vasectomy patient who underwent the surgery without anesthesia because he was mistakenly injected with saline solution rather than lidocaine. She also tells the story of a woman whose severe headaches went away after being injected with saline. The latter swore that only Demerol worked for her, but she had been conditioned to feel relief when she got a shot.

So, the next time you are wondering how healers can cure people with a simple touch or by waving their hands in the air over a body part or by uttering some ineffable incantation, think that maybe, just maybe, some sort of conditioned response is going on. You don't have to call it a placebo response, but if you do, don't assume that classical conditioning is the only explanation for placebo effects. There may be other explanations for some placebo responses and the issue may be more complicated than you think. It is unlikely that the "healer" unblocked chi, evoked the assistance of a supernatural being, transferred her animal magnetism, unleashed a vital force in the memory of water, or erased memories of pain by tapping your tummy. Remember the old saying: when you hear hoof beats, think horses not zebras. Well, when you hear of magical healing, think classical conditioning, natural regression, misdiagnosis, symptom fluctuation, patient politeness and subordination, or a host of other things. Your first inclination might be to think magic or miracle, but first inclinations may be responses to the availability bias. If it's truth you're after, you might want to consider alternative explanations to what your intuition tells you.

Monday, March 19, 2012

false implication

What do each of the following products have in common?

    Berry Berry Kix
    Country Time® Lemonade Flavor Drink
    Cap'n Crunch with Crunch Berries
    Dannon Danimals XL (Strawberry Explosion)
    Froot Loops
    Fruity Cheerios
    Juicy Fruit Gum
    Life Savers (Wild Cherry)
    Nestle Nesquik milk and drink mix (strawberry)
    Post Fruity Pebbles
    Push Pop (cherry)
    Ring Pop (cherry)
    Tang
    Trix cereal
    Trix yogurt (strawberry kiwi)
    Yoplait Go-Gurt yogurt (Strawberry Splash)
      They contain no fruit. But the labels and ads used to attract consumers to these products falsely imply that fruit is one of their ingredients.

      What does "no cholesterol" mean when printed on a bag of carrots or on a soft-drink can? (You might get some cholesterol with your carrot if it's fried in animal fat and your soda might contain cholesterol if it's made with pork rinds.) "No cholesterol" printed on a bag of potato chips may falsely imply that the fat used to fry the potatoes won't be turned into cholesterol when you eat the chips. For some people, I suppose, the words might even falsely imply that potato chips are a healthy food.

      A package of Healthy Choice lunch meat says that it is 97% fat-free, which is true if measured by weight, but 25% of its calories come from fat. That right, a product that implies it is very low in fat actually provides a healthy amount of fat with each serving. The dairy industry also cleverly expresses fat content as a percentage of weight rather than percentage of calories. Otherwise, it would tell you that the milk it now calls 2% is actually 31%.

      Advertisers and those who market commercial products aren't the only ones who try to use false implications to their advantage. When Sandra Fluke, a third-year law student at Georgetown University, spoke out in favor of the Obama administration's Patient Protection and Affordable Care Act, especially the requirement that insurers cover preventive care services, including contraception, she was attacked by popular conservative radio entertainer Rush Limbaugh. Limbaugh said: "If we’re going to pay for your contraceptives and thus pay for you to have sex, we want something for it. We want you to post the videos online so we can all watch."

      Besides expressing himself in his familiar vulgar way, Limbaugh falsely implied that Fluke wanted the taxpayer to pay for her birth control. This implication was false on two counts. The issue had nothing to do with taxpayers covering the cost of anything. It was about what insurers would be required to cover by the government. And, more important, Fluke spoke in support of contraception as basic health care for several reasons and not one of those reasons involved her desire to have sex and not get pregnant. She said:

      Last month, students from several Catholic universities gathered to send a message to the nation that contraception is basic health care. I was among them, and I was proud to share the stories of my friends at Georgetown Law who have suffered dire medical consequences because our student insurance does not cover contraception for the purpose of preventing pregnancy.

      I joined these students in speaking at a media event because I believe that stories of how real women are affected are the most powerful argument for access to affordable, quality reproductive health care services....

      They are women with polycystic ovarian syndrome, who need contraception to prevent cysts from growing on their ovaries, which if unaddressed can lead to infertility and deadly ovarian cancer. They are sexual assault victims, who need contraception to prevent unwanted pregnancy.

      They are Catholic women, who see no conflict between their social justice -based faith and family planning. They are new moms whose doctors fear that another pregnancy too soon could jeopardize the mother's health and the potential child's health too. They are mothers and grandmothers who remember all too well what it was like to be called names decades ago, when they were fighting for a job, for health care benefits, for equality.

      They are husbands, partners, boyfriends and male friends who know that without access to contraception, the women they care about can face unfair obstacles to participating in public life. And yes, they are young women of all income levels, races, classes and ethnicities who need access to contraception to control their reproduction, pursue their education and career goals and prevent unintended pregnancy. And they will not be silenced.
      Another person who won't be silenced is Republican presidential candidate Rick Santorum. On the ABC program "This Week," Santorum said “62 percent of kids who enter college with some sort of faith commitment leave without it.” He admitted that he might not have the exact statistic. “I suspect it may even be worse,” he said. One implication of his claim seems to be that had these kids not gone to college, they'd still be religious, which is false. PBS earlier this month tracked down the study Santorum refers to, but it actually suggests that people who have not enrolled in college are even less religious than those who do. “64 percent of those currently enrolled in a traditional four-year institution have curbed their attendance habits,” said the study, published in the journal Social Forces. “Yet, 76 percent of those who never enrolled in college report a decline in religious service attendance.”
      Another study, published last year in the Review of Religious Research, found that for each year of education after 7th grade, seemingly contradictory trends emerge: people become more likely to attend religious services and to believe in a “higher power” but at the same time they are less likely to say the Bible is the “actual word of [a] god” and become more open to believing there is truth in more than one religion.

      Anti-vaxxers and abortion

      One argument presented by some anti-vaxxers is that vaccines contain cells from aborted fetuses. A charitable interpretation of this claim is that it is a false implication based on the fact that:
      The rubella vaccine virus that is included in the MMR (measles, mumps and rubella) shot is cultured using human cell lines. Some of these cell lines were started from fetal tissue that was obtained in the 1960s from legal abortions.*
      However, the anti-vaxxers, such as Joe Mercola, fail to mention that no new fetal issue is required to generate rubella vaccine.

      Monday, March 12, 2012

      availability bias

      When I read that Judy Collins would be performing at the Freight and Salvage Coffehouse in Berkeley, I didn't hesitate to order tickets. After I'd shelled out more than $100 for two tickets, I began to question my judgment. Judy Collins was born in 1939. This is 2012. My memories of her are of recordings I own, most of them dating from the 1960s and '70s. She had a beautiful voice and wrote some fantastic songs. My impulsive act is an example of the availability bias at work. The first thing that popped into my mind on reading about her upcoming appearance at The Freight was of her singing songs like "Both Sides Now," "My Father," and "Someday Soon." (Those memories are very pleasant; there was affect bias involved in this decision, as well.) My decision to drive 150 miles (round trip) to see and hear Judy Collins was not based on any knowledge I had of what her voice or her performances are like now. I should have investigated a bit before investing time and money that I might later regret. After the fact, I checked out TicketMaster fan reviews. The first one goes like this:
      Not only did we enjoy the show entirely. The non-stop performance that she did was just unbelievable. She did not even drink water. Judy is 71, and her voice has remained the same for all these years! She did a vast array of songs ranging from Christmas Carols to children's lullabies and, of course, the standard favorites. I would go and see her again. Audience participation was great! 
      Favorite moment: When she replaced the pianist, who was extraordinary, and played six songs back to back without stopping. She is just an amazing pianist herself!
      Wonderful! Now confirmation bias can kick in! The glowing review was a couple of years old, however. The next review on the list was dated just a few days ago and it read: "Beautiful, talented and ever elegant. I saw Judy in 1969 and she is just as good now. It was a terrific night all around." There were six more highly positive reviews, all dated within the last couple of weeks. (There were over 150 reviews and very few were totally negative.) Now I think I've made a good decision, but not for a very rational reason. I based my decision to go to a Judy Collins concert on the first thing that popped into my mind and the pleasantness of the memories aroused. Other things should have been considered before making the decision. I've heard other singers performing past their prime and it wasn't pretty. She's over 70 and her voice is unlikely to be what it was forty years ago. I feel better now that I've found some recent positive reviews. However, for all I know these positive reviews are written by shills or people who are easily pleased. I don't think that's likely, but it's possible. If I were a thorough investigator I'd seek out reviews by professional reviewers, but one of them might be really negative and say things about her recent performances that would make me second-guess my decision. Since I've already made the decision, why look for a wound and some salt to rub into it? (When I told a friend that I had tickets to see Judy Collins, he told me that he had heard her on a PBS program recently and her voice was cracking. She was no longer a solid soprano and her voice was cigarette-rough. But he's old and his hearing is going and ....)

      The availability bias is a cognitive bias involving making quick judgments based on the speed with which memories are aroused and become available to the conscious mind. The main factors influencing the speed with which memories present themselves are recent frequency of similar experiences or messages, or the salient, dramatic, or personal nature of experiences. In our culture, the mass media play an important role in affecting what comes to mind quickly when we think of the frequency, importance, or causes of things. Rational judgments should be made on the basis of a consideration of all the relevant evidence, but many judgments we consider rational are made based on the ease with which they come to us. For example, a person might decide not to take a cruise to Alaska that she was about to book when she heard about the cruise ship Costa Concordia striking a reef near the Tuscan island of Giglio, killing more than 20 passengers. The safety of a cruise to Alaska has not diminished because of what happened off the coast of Italy, but the news reports and videos immediately bring to mind the horror of dying on a capsized cruise ship. The decision not to take the planned cruise has been biased by the news of the Costa Concordia. Likewise, many people refuse to fly on a commercial airliner because someone they love died in an airplane crash, yet these same people will drive thousands of miles every year rather than fly, even though they are more likely to be killed in an automobile crash than in an airliner crash.

      When asked for your opinion on teenage drug use, premarital sex, morals of politicians, good stocks to invest in, the incidence of violent crime, or any other subject that mass media outlets are likely to cover, the odds are that your answer will be based on what comes immediately to mind and that will be heavily influenced by what you've read, seen, or heard recently in the mass media. Or, your answer will be heavily influenced by personal experience. What is unlikely is that your opinion will be based on objective or scientific knowledge of the subject. This tendency to make judgments by the ease with which ideas come to mind is called the availability heuristic.

      Consider, for example, how people think of violent crime in the United States. During a five-year period in the 1990s, the homicide rate nationwide dropped by 20 percent, but coverage of murders on the national evening news programs at ABC, CBS, and NBC went up by 721 percent.  (Vincent Schiraldi, the Justice Policy Institute, 1998, cited in Carroll, Becoming a Critical Thinker, 2005, p. 62.) What do you think had more influence on people's perception of the incidence of homicide in our country? The crime rate decreased all through the 1990s, and for the last decade crime rates have remained steady. Yet, between 52% and 89% of Americans every year since 1990 have thought that crime is on the rise.* It's not just the excessive coverage of crime by the news media that influences our judgments about crime; entertainment programs also play a part in contributing to our misinformed minds. Consider this press release from Purdue University:
      People who watch forensic and crime dramas on TV are more likely than non-viewers to have a distorted perception of America's criminal justice system, according to new research from Purdue University.

      "These kinds of shows, such as 'CSI: Crime Scene Investigation,' 'Law & Order,' 'Cold Case,' and 'The Closer' are some of the most popular programs on television today, so it's important that we understand how they might influence people," says Glenn Sparks, a professor of communication who studies mass media effects. "We know they have inspired people to pursue careers in forensic science and law enforcement, but what are some of their other effects? We found that people who watch these shows regularly are more likely to overestimate the frequency of serious crimes, misperceive important facts about crime, and misjudge the number of workers in the judicial system."

      Heavy TV-crime viewers estimated two and a half times more real-world deaths due to murder than non-viewers. Lawyers and police officers each make up less than 1 percent of the work force, but those surveyed estimated the percentage of the work force in those professions at more than 16 percent and 18 percent, respectively.

      Saturday, March 3, 2012

      straw man fallacy

      The straw man fallacy is a common rhetorical tactic whereby one gives the impression of attacking a position or argument that another has taken while actually attacking a false, distorted, misleading, weakened, or exaggerated version of that position or argument. For example, President Obama is regularly called a socialist by conservative pundits and politicians whenever he proposes any government action, but they are attacking a straw man. Obama's proposals on health care, bailouts, and other government interventions in public life are not part of a socialist agenda. Obama is no more a socialist than Rick Santorum is an agent of the Vatican. Obama's defenders also attack a straw man when they characterize his critics as claiming that "Obama wants to seize the money of hardworking Americans and redistribute it to single mothers and jobless crackheads ... until we resemble the Soviet Union." Obama's critics have distorted his proposals, but to say they're portraying him as wanting to redistribute the wealth to support jobless crackheads is a bit of an exaggeration.

      An important consequence of attacking straw men instead of real arguments in their strongest form is that doing so prevents serious discussion of whatever issue is at stake. The bar for moral, social, and political discourse in this country isn't that high to begin with, but attacking straw men lowers the bar even further.

      Republican presidential candidate Rick Santorum provided us with some examples of the straw man fallacy in his attacks on President Obama's position on education and John F. Kennedy's position on separation of church and state. Here is what Santorum said regarding Obama's views on college education:
      President Obama said he wants everybody in America to go to college. What a snob! There are good, decent men and women who go out and work hard every day and put their skills to test that aren’t taught by some liberal college professor trying to indoctrinate them. Oh, I understand why he wants you to go to college. He wants to remake you in his image. I want to create jobs so people can remake their children into their image, not his.
      Obama did not say he wants everybody in America to go to college, so attacking him for holding this position is irrelevant to either proving Obama's position is wrongheaded or for proving any of the other claims Santorum makes about getting a college education, creating jobs, or indoctrination. What Obama actually said was:
      I ask every American to commit to at least one year or more of higher education or career training. This can be community college or a four-year school; vocational training or an apprenticeship. But whatever the training may be, every American will need to get more than a high school diploma. And dropping out of high school is no longer an option. It’s not just quitting on yourself, it’s quitting on your country — and this country needs and values the talents of every American.
      Santorum's straw man ploy was matched by others who characterized Santorum's position as being against education, which it isn't. Comedian Jon Stewart, for example, asked of Santorum: “You’re against people educating their kids because it’s fancy?” We can forgive Stewart, since exaggeration is an expected part of comedy. But others who distorted Santorum's position are as guilty of the straw man fallacy as he is.

      Regarding JFK's position on separation of church and state, Santorum said:
      To say that people of faith have no role in the public square? You bet that makes you throw up. What kind of country do we live [in] that says only people of non-faith can come into the public square and make their case?

      That makes me throw up and it should make every American who is seen from the president, someone who is now trying to tell people of faith that you will do what the government says, we are going to impose our values on you, not that you can’t come to the public square and argue against it, but now we’re going to turn around and say we’re going to impose our values from the government on people of faith, which of course is the next logical step when people of faith, at least according to John Kennedy, have no role in the public square.
      I admit that it is difficult to follow what Santorum is saying, but it seems clear that he is characterizing Kennedy's position on the separation of church and state as meaning that people of faith have no role to play in our political life. In actuality, Kennedy's position was put forth to defend the position that a person's faith should not disqualify him from public office. Kennedy never said that he wanted people of faith to have no role in the public square. I remember the speech well and Kennedy's point was clear: if elected I will not be taking orders from the Vatican. Here's what Kennedy actually said:
      I believe in an America where the separation of church and state is absolute, where no Catholic prelate would tell the president (should he be Catholic) how to act, and no Protestant minister would tell his parishioners for whom to vote; where no church or church school is granted any public funds or political preference; and where no man is denied public office merely because his religion differs from the president who might appoint him or the people who might elect him.

      I believe in an America that is officially neither Catholic, Protestant nor Jewish; where no public official either requests or accepts instructions on public policy from the Pope, the National Council of Churches or any other ecclesiastical source; where no religious body seeks to impose its will directly or indirectly upon the general populace or the public acts of its officials; and where religious liberty is so indivisible that an act against one church is treated as an act against all.
      Nothing in this speech comes close to Santorum's distortion.