Monday, June 08, 2009

*** How we decide by Jonah Lehrer

You'll be surprised to discover that many of your decisions come from your subconscious - and that's a good thing. Because if you had to consciously decide about everything, you'd probably never do it in time, and you may end up getting something you'll be unhappy with. In fact, what the book stresses is that in complex areas where you are expert or highly experienced, you should trust your gut (emotions) - not your conscious brain. In areas where you are not expert, or where the decision criteria are not complex, go with the higher brain, and discount the emotions. I hope you decide to read this posting ;)

Think Fast Batter

A typical major league fast ball takes .35s (350ms) to travel the pitcher’s hand to home plate. Unfortunately for the batter, it takes .25s (250ms)for his muscles to initiate a swing. It takes a few milliseconds for the visual info to travel from the retina to the visual cortex, so batter has only about 5ms to perceive the pitch and decide to swing. But people can’t think that fast, even under perfect conditions. It takes the brain 20ms to respond to sensory stimulus. So how does the batter mange to hit a fastball? The answer is that his brain subconsciously picks up data about the pitch long before the ball leave’s the pitcher’s hand. P25

 Motion Sickness is about error correction

Motion sickness is largely the result of a dopamine prediction error; there is a conflict between the type of motion being experienced – the rocking of a boat – and the type of motion expected – unmoving ground. The result in this case is nausea and vomiting. [I’ve heard that the brain suspects food poisoning for this mismatch and hence the nausea. –Ben] It doesn’t take long before the dopamine neurons start to revise their models of motion; this is why seasickness is usually temporary. After a few horrible hours, the dopamine neurons fix their predictions learns to expect the rocking. P42 And then when you get back to shore, you can become landsick too.

When the dopamine neurons are working properly, they are a crucial source of wisdom. The emotional brain effortlessly figures out what’s going on and how to exploit the situation for maximum gain. P42

The brain’s cells measure the mismatch between expectation and outcome. They use the inevitable errors to improve performance; failure is eventually turned into success. P46


Here is an experiment that highlights that the subconscious emotional brain is able to learn before the conscious logical brain.

On average people had to turn over 50 cards before they figured out the pattern to earn more money. But it took 30 cards beyond the 50 – 60% more – before the average person could explain why this pattern worked... What scientists found was that after only 10 cards, a player’s hand got nervous when it reached for negative decks… The emotions had developed an accurate sense of fear… The experiment was repeated with injured patients whose brains were damaged and thus had no emotional response. They never developed the symptoms of nervousness – and they also never figured out the pattern. When the mind is denied the emotional sting of losing, it never figures out how to win. P47

Dopamine neurons automatically detect the subtle patterns that we would otherwise fail to consciously notice; they assimilate all the data that we can’t consciously comprehend. P48

Your gut feelings explained.

Even when we consciously think we know nothing, our brains may know something if we get vague sensations of unease or pleasure. P48 

The most effective way to get better is to focus on your mistakes. You need to consciously consider the errors being internalized by your dopamine neurons. P51

“An expert is a person who has made all the mistakes that can be made in a very narrow field.” – Niels Bohr, physicist


Before your neurons can succeed, they must repeatedly fail. There are no shortcuts for this painstaking process. P54 Many studies now state that it takes about 10,000 hours to become a world class expert in a particular field. At 20 hours a week, that is 10 years of practice.

Why gambling is addictive

13% of patients taking dopamine boosting drugs develop severe gambling compulsions… Why does an excess of dopamine make games of chance so irresistible? The answer reveals a serious flaw in the human brain… Think about a slot machine from the perspective of your dopamine neurons. The purpose of these cells is to predict future events… While putting quarter after quarter into the slot, your dopamine neurons are struggling to decipher the patterns in the machine (which is fruitless since there is not pattern)… But here’s the catch; while dopamine neurons are excited by predictable rewards – they increase their firing when surprised with a reward. Such unpredictable rewards are 3 to 4 more exciting… The purpose of this reward is to make the brain pay more attention to new and important stimuli. P60


Why do we believe in streaky shooters/hitters/scorers,etc.? Our dopamine neurons are to blame… The danger of random processes is that they take advantage of a defect built into the emotional brain. The dopamine neurons get such a thrill from watching a prediction come through that our brains completely misinterpret what’s actually going on. We trust our feelings and perceive patterns, but the patterns don’t actually exist. P65 Would you enter in the last winning lottery number for the next upcoming event? Why not? It has the same chance as any other combo, but most people won’t. This is a flaw of your dopamine system. You’d feel compelled that the system is due to pick a new number. But all sequences are equal.


Harry Markowitz, the Nobel prize winning economist, who invented portfolio diversification theory, couldn’t bring himself to use his own equations. When he divided up his investment portfolio, he ignored the investment advice that had won him the Nobel, and split his portfolio equally between stocks and bonds. P78


Loss aversion causes bad investment decisions. Even hypothetical losses. Say you sell a stock that then goes up 50%. You will perceive that as a loss, even if you nominally profited… This will lead you to chase and invest after a run up, when the risks are now favoring a pullback. This is what inflates and eventually bursts a bubble. Hypothetical losses, compel folks to join the party and profit.

Loss aversion is innate flaw. Everyone who experiences emotion is vulnerable to its effects. Its part of a larger phenomenon known as negativity bias, which means that bad is stronger than good. In marital interactions, it takes 5 kind comments to compensate for 1 critical comment… Investment losses hurt twice as bad as a gain pleases. P81

Want to save more? Only spend your cash

Brain imaging suggest that paying with credit card actually reduces activity in the insula, a region associated with negativity… Spending money with a credit card doesn’t feel bad, so you spend more…  In experiments, the average credit card bid on auction items is twice as high as a cash bid. P85 

Subjects in an MRI were offered a small gift certificate now, or a larger one in 2 to 4 weeks… These 2 options activated very different neural systems… The future gift activated the prefrontal cortex, which is associated with rational planning… But when a subject thought about getting the immediate option, the emotional/dopamine driven brain was turned on. P88

Patients with damaged pre-frontal cortexs can’t hold back their emotions. If they get angry, then they’ll just get in a fight. Even if they know it’s a bad idea – the cognitive knowledge is still there – but that knowledge is less important than what they’re feeling. P104

Would rather buy meat that is 85% lean, or 15% fat? Would rather opt for surgery with an 80% survival rate, or a 20% chance of death? Twice as many favor the former over the latter, but they are equal. Why the difference?... When a person thinks about losing something, the amygdala is automatically activated, generating negative feelings. That’s why people hate losses so much. P106

The scientists were intrigued by the subjects who weren’t swayed by the different frames (85% lean/15% fat, 80% survival/20%death)… They discovered that the amygdalas of these rational people was still just as active… It was the activity of the prefrontal cortex that best predicted decision of the subjects… People who are rational don’t perceive emotion less, they just regulate it better… If the amygdale is simply responding to a loss frame, then it can be discounted. The prefrontal cortex can deliberately choose to ignore the emotional brain.  P107 Did you read that carefully? All those folks whom you think of as cold and calculating, actually are quite emotional, and have active amygdalas causing pain and dopamine neurons causing pleasure just like everyone else. However, they are able to control their emotions with their higher brain. They feel love, hate, loss, sadness, joy just like everyone else – but they may not express it outwardly.

Seems that all you needed to learn wasn't in Kindergarden but before, when you're only 4

There was strong correlation between the behavior of the 4 year old waiting for a marshmallow and that child’s future behavior. The children who couldn’t wait a minute were much more likely to have behavioral problems later on. They got worse grades and were more likely to do drugs. They struggled in stressful situations. Their SAT scores were 210 points lower on avg than those kids who could wait a few minutes. In fact, this small test turned out to be a better predictor of SAT results than the IQ tests given to the same 4 year olds. P112

 Want to get smarter? Increase your short term working memory by memorizing this passage

The brain has a special kind of memory – short term working memory – where data streaming in from all cortical areas can be manipulated and analyzed. This allows the brain to determine what info, if any, is relevant to the problem its trying to solve. Studies show that neurons in the prefrontal area will fire in response to a stimulus and then keep on firing for several seconds after the stimulus disappears. This echo allows the brain to make creative associations as seemingly unrelated sensations and ideas overlap… Numerous studies have shown strong correlations between scores on working memory and tests of general intelligence. Being able to hold more information in the prefrontal cortex, being able to hold onto that info longer, means that brain cells are better able to form useful associations. P131

Novice: Think before you do Expert: Do before you think 

Novice golfers hit better shots when they consciously reflect on their actions… By paying attention to the mechanics of the stroke, the novice can avoid mistakes… When experienced golfers are forced to think about their putts, they hit significantly worse shots… When you are playing at a high level, your skills are automated. You don’t need to pay attention to every step that you’re doing. Researchers believe that this is what happens when you ‘choke’. The part of the brain that monitors behavior starts to interfere with decisions that are normally made without thinking… The worst part about choking is that it tends to be downward spiral. The failures build on one another, and a stressful situation is made more stressful. P138 

Thinking too much can affect your test score. When a group of Stanford sophomores were told that a test was going to measure their intelligence, the white students scored significantly higher than the black ones… But when another group was told the same test was merely preparatory drill and not an intelligence measure, the scores were virtually identical… The discrepancy was caused by stereotype threat in the black students. They start to think ‘I should be careful, and not mess things up.’ The more you do that, the more you’ll get away from your intuitions that help you. They think they did well because they are trying so hard, but they are not. P140

A recent study found that when a person travels more than 1 hour in each direction to work, he/she has to make 40% more in order to be as satisfied with life. P145

Placebo Effect Explained

When people were told they received the pain reliever (a placebo actually), their front lobes responded by inhibiting the activity of their emotional areas that normally respond to pain. Because the people expected to experience less pain, they ended up experiencing less pain. Their predictions became a self fulfilling prophecy. P146

Let’s say you’re given the choice between chocolate cake and healthy fruit. Now let’s say before choosing you’re asked to memorize a 7 digit phone number. One group was asked to choose w/out memorizing, and another with. The 7 digit group overwhelmingly (59% to 37%) chose the cake. Why? The effort to memorize the numbers drew cognitive resources away from the part of the brain that normally controls emotional urges. Because working memory and rationality share a common cortical source – the prefrontal cortex – a mind trying to remember lots of information is less able to exert control over its impulses. P151

The brain runs on glucose, and when it runs low it explains why we get cranky when we are hungry and tired. The exhausted brain is less able to suppress the negative emotions sparked by small annoyances. A bad mood is really just a rundown prefrontal cortex. p152

When the prefrontal cortex is overwhelmed, a person can no longer make sense of the situation... In the latest clinical guidelines, doctors were strongly recommended not to obtain imaging or other diagnostic tests in patients with non-specific back pain. In too many cases, the expensive tests proved worse than useless. All of the extra detail just got in the way. The doctors performed better with less information. p164 Psychiatrists estimate that 25% of the prison population have psychopathic tendencies... whose neurological condition is best defined in terms of a specific brain malfunction: psychopaths make poor moral choices... On most psychological tests, they appear perfectly normal. Working memory isn't impaired, language is fine, they don't have reduced attention spans. They often have higher than average IQs and reasoning abilities. But they have damaged emotional brains... When normal people are shown staged videos of people receiving shocks, their hands sweat and their blood pressure surges. Psychopaths feel nothing... In the most violet types, violence actually lowers their blood pressure. The acts of violence have a calming effect... The main problem is a broken amygdala, the area responsible for propagating fear and anxiety. As a result psychopaths never feel bad when they make others feel bad... Without suffering negative emotional consequences, they never learn from their adverse experiences. They are 4 times as likely to commit crimes after being released from prison. p171 We've assumed that our normal moral decisions are the byproduct of rational thought... But this argument miss the central reality of moral decisions, which is that logic and legality have little to do with anything. p173 The evolution of morality required a whole new set of decision making machinery. The mind needed something that would keep it from hurting other people while it sought pleasure and safety... These new neuaral pathways are a very recent biological adaptation. These moral circuits can be found in only the most social primates. And we of course are the most social primates of all. p176 An assessment of US soldiers from WW2 found that only 20% actually shot at the enemy, even when under attack. It is the fear of killing, rather than the fear of being killed, that is the most common cause of battle failure... At the most vital point of battle, the soldier becomes a conscientious objector... These findings led to new training techniques and tactics which increased the rate to 55% in Korea, and to 90% in Viet Nam... Soldiers no longer felt a surge of negative emotions when they fired their weapons. They had been turned into killing machines. p180 Autism has nothing to do with psychopathy. Psychopaths can readily recognize when others are upset or in pain. Their problem is that they can't generate corresponding emotions and remain preternaturally calm. People with autism don't have a problem generating emotion. Their problem is recognition; they struggle to decipher the mental states of others. p185 The problem with facts and statisitcs is that they don't activate oru moral emotions... This is why we are riveted when one child falls down a well but turn a blind eye to the millions who die every year for lack of clean water. p188 Genetics can alter brain development. But there's another way that the developing brain can be permanently damaged: child abuse... Cruelty makes us cruel. Abuse makes us abusive. Its a tragic loop. p189 In the brain of shopper a crucial part of the dopamine reward pathway is activated when we encounter something we desire. But then comes the price tag, which activates the prefrontal cortex and insula. The insula produces negative feelings like nicotine withdrawal, and seeing pictures of people in pain. We avoid things that make our insulas excited. This includes spending money. The prefrontal cortex is activated to balance these two - pleasure and pain - and to make the final purchase decision... Therefore retailers must not only excite the dopamine pathway with lures of pleasure, but also inhibit the insula. They do this by repeatedly assuring the insula by 'guaranteeing the lowest' or 'wholesale' price, offering sales or hot deals. p202 Paying with plastic literally inhibits the insula, making a person less sensitive to the cost of an item. p202 Experts and pundits often suffer from cognitive errors in that they selectively interpret the data so that it proves them right. They'll distort their thought process until it leads to the desired conclusion. p207 In an experiment, 284 people who make a living offering political and economic advice were polled on their predictions. This led to 82,361 different predictions... They tended to perfrom worse than random chance, and selected the right answer only 3.3% of the time... The most famous in the study tended to be least accurate. Why? False certainty which led the experts to mistakenly impose top down solutions. p209 The best pundits and experts are able to state their opionions in testable form so that they can continually monitor their performance. p209 Conscious deliberation over a host of options doesn't lead to the best decision! In a study, those who carefully contemplated each alternative - chose the ideal option only 25% of the time. They performed worse than random. However, when subjects were distracted for a few minutes - those who were forced to choose with their emotions - found the best option 60% of the time. p234 Following IKEA shoppers, researchers found that the longer people spent analyzing their options, the less satisfied they were with their decisions. Their rational faculties had been overwhelmed by the store and they ended up choosing the wrong couch when IKEA has over 30 choices. The shoppers did best when listening to their emotional brains. p235 Use your consciuos mind to acquire all the info you need for making your decision. But don't try to analyze the info with your conscious mind. Instead take a break while your unconscious digests it. Whatever your intution tells you is almost certainly going to be the best choice. p237 As long as someone has sufficient experience in that domain - he's taken the time to train his dopamine neurons - then he shouldn't spend too much time consciously contemplating the alternatives. p237 It is the mundane math problems of daily life that require conscious thought. These won't overwhelm the prefrontal cortex, and they are so simple that they actually trip up the emotional brain, which can't compare prices or compute odds. p238 The prefrontal cortex can handle only about 4 distinct variables (maybe 5 to 9 with practice), but it can be a useful tool to evaluate simple scenarios rationally. What are best suited problems for it? Ask if the decision can be accurately summarized into numerical terms, or any domain where the details of the product aren't particularly important (then focus on price)... Important decisions about complex items, categorizing by price alone will eliminate alot of essential info. Here is where you should rely on your emotions to guide you... New problems should not rely on emotions, since those rely upon experience. You must stop and think and let your working memory tackle the dilemma. The only way out of a unique mess is to come up with a creative solution. p246 There 2 tricks to help ensure that you never let certainty interfere with your judgment. First, always entertain competing hypotheses (devil's advocate). Second, remind yourself of what you don't know. p247 Colin Powell "Tell me what you know. Then tell me what you don't know, and only then can you tell me what you think." p248 The reason emotions are so intelligent is that they've managed to turn mistakes into educational events... But there are no shortcuts to this painstaking process; becoming an expert takes time and practice. But once you've developed expertise in a particular area - it's important to trust your emotions when making decisions in that domain... And yet it doesn't mean that the emotional brain should always be trusted. Sometimes it can be impulsive and short sighted or oversensitve to patterns. But you should always be considering your emotions when weighing an important decision. p249 .04 aircraft fatalities per 1 million passenger air miles vs. .86 driving. 
OK. Let's do a little math to show the truth about air travel. When the plane goes down, all passengers go down together, so lets see how many deaths happen per hour of flying vs. driving, not using this bogus passenger airmile figure.
Assume each plane can carry 220 passengers on avg, and flies at 500 mph
Assume each car carries 1.1 passengers on avg and travels at 50 mph
That means per HOUR the plane covers 220x500=110,000 passenger miles, and the car 1.1x50=55 passenger miles. This means that the plane per hour is 2000 times higher in passenger airmiles, but in terms of vehicle operation per hour, we need to multiple the fatality rate by 2000 to discover the fatalities per hour of airtravel. That figure is .04 x 2000 = 80. That figure is actually almost 100 times higher than that for an automobile per hour of driving.


1 comment:

Librarian said...

Recently, a close friend whose opinion I value a lot has recommended "How we decide" to me, and I am now about half way through. Suddenly, quite a few things make much more sense, and I am learning a lot (something I truly enjoy).

I think I will follow your blog. It looks interesting.