How we decide

Who knows what I want to do? Who knows what anyonewants to do? How can you be sure about something likethat? Isn't it all a question of brain chemistry, signals goingback and forth, electrical energy in the cortex? How do youknow whether something is really what you want to do orjust some kind of nerve impulse in the brain? Some minorlittle activity takes place somewhere in this unimportantplace in one of the brain hemispheres and suddenly I wantto go to Montana or I don't want to go to Montana.—DON D E L I L L O , White Noise

Overview

The brain has two "halves", the rational left hemisphere and intuitive, emotional right hemisphere

Good decision making requires judicious use of both

Use Emotional brain when no time to make a decision (or if there are too many variables)

Use Rational brain when faced with completely unfamiliar situation

Plato’s horses

Reason

Emotion

Plato – Successful person – Reason horse is more in control

Do we need emotions

Plato - Emotions not requiredDescartes - Human beings are rational

David Hume -Scottish philosopher - Reason is the slave to passions - is right

Seat of emotion - Orbitofrontal cortex (orbito=eye socket in latin)

Antonio Damasio - – Elliots Tumour When OFC is removed, people cannot make simple decisions (parking car, what to eat, use blue or black pen)

Emotions in decision making

Making quick decisionsPilot with engine on fire, Quarter back in american footballReason for flight simulator training is to train in lot of situations

Too many variables in decisions

Making daily soaps - no luxury of retakes Most important decision - casting

Deciding on a house

When the mind makes a choice (good food, romantic prospect etc) it has already considered the alternatives - the analysis takes place outside conscious awareness

Consciousness is a small part of the brain, it is slave to everything that works underneath

Feelings and behavior

• Charlie track scenario – kill 1 or 5– Two scenarios– Why does one feel very wrong ?

• Feeling drives moral behavior

Emotions and Dopamine

• Gulf war - Commander had to decide whether radar blip was friendly jet or Iraqi silkworm missile

• Olds and Milner – 1954 – discovery of dopamine

• Nucleus Accumbens – generates pleasurable feelings

• Experiment- Electrodes in NaCC - Too much pleasure - excess dopamine - fatal to rats – can die of overhappiness

Role of Dopamine

• Wolfram Schultz - Neuroscientist• Gave monkeys apple juice, dopamine neurons fire• More apple juice, dopamine neurons started to fire less

– Same with ipad, ipod etc, after a week the dopamine doesn’t fire (maybe little longer for a house)

• Prediction neurons (if juice not given, error correction – learning)

• Brain learns by making mistakes

Dopamine neurons fire here

O-shit circuit, alerts to some abnormal thing

Learning and the ACC

• Experiment – Monkeys with Joystick - Lifting or turning would provide reward - switched after every move.

• Monkeys with ACC removed had problems learning from their mistakes.

• People with genetic defect that reduces dopamine receptors in ACC are less likely to learn from negative sequences, more addicted to drugs/alcohol

• ACC - has spindle neuron - long and slender - other neurons are short and bushy - for communicating effects of dopamine quickly to the rest of the brain

Emotions versus logic

• Iowa gambling task - four card decks, each card told player whether he had won or lost money. Two were rigged (reward 100, penalty 1250), the other had lower reward (50) but no penalty. It took about 80 cards to learn the logic of drawing from the second pack but after 10 cards, the emotions detected the wrong packs

• Logic is slow

• Neurologically impaired people who could not feel emotions were never able to learn the rules.

• Stocks you feel good about - emotional brain can identify the best stocks

Fooled by feeling

• Parkinsons disease - of dopamine system - neurons start to die in part of brain that controls body movements

• Treatment - requip - increases effectiveness of remaining neurons to transmitting dopamine - lead to gambling

Metacognition

• Cant remember a name but we know that we know it (tip of tongue)

• Aware of being aware

Dopamine and overconfidence

• Hot hand in baseball• T-shaped maze - food with 60% probability at left, rats

discovered this and always went to left of maze, got accuracy of 60%. Yale undergraduates got 50% on the same experiment

• Dopamine can make random processes seem like patterns (e.g. stock market successes can lead to feeling of infallibility)

• Regret can induce wrong decisions (overcompensate for a bad past decision)

Loss aversion

• Kahnemann and Tversky• $1.75 to $2 for a bet of $1• For every critical thing you say to someone (e.g. spouse)

you have to say 5 nice things to make up for it– Nice things don’t last that long in memory

• People more likely to sell a stock that has gone up– The brain doesn’t want to take a loss– Leads to a portfolio of loss making stocks

Deal or no Deal

• Briefcases with various amounts ($1, $10000, $500000)

• Participants made offers by banker• Best strategy – accept anything above mean of

the remaining money

Pre-frontal cortex – The seat of reason

Damage to PFC – People are driven entirely by emotions

Cannot contain self-destructive behavior

The uses of reason

• Firefighting incident• DC-10 with stabilizer

gone (UA flight 232)

• Need to keep emotions in check sometimes

Framing problem

• Brain avoids something framed as loss – Example – Rs 100000

• Surgery– 80% chance of surviving instead of 20% dying

Delayed gratification

• Marshmallow test - 4 year olds– Students who could delay

gratification did better academically (12 years later)

• Adolescents are less rational– Engage in more risky and

impulsive behavior– Max number of car

accidents in teen groupsMarshmallows

Stroop task

Green Red BluePurple Blue Purple

Stroop test

Blue Purple RedGreen Purple Green

Choking on thought

• Opera singers, Golf players - Thinking about performance degrades the performance at the expert level

• Jam test – when asked to explain why they preferred jams, students did badly– Thinking too much leads us to focus on all sorts of

variables and degrades decision making

Choking on thought

• Baba Shiv - Stanford - Energy drink - one at 30% discount, people who drank the discounted drink solved fewer puzzles than the ones who paid full price.

• Cake vs fruit salad - people who were asked to remember seven digits chose cake and people who were asked to choose two digits chose fruit salad, a mind trying to remember lots of information is less able to exert control over impulses

• Last two numbers of social security number- those with higher last two digits bid more

• Stocks - people who saw only the prices made better decisions

Functional magnetic resonance imaging

• Tool for brain research• Enables visualization of blood

flow (closely linked to neural activity)

• For a typical fMRI scan, the 3D volume of the subject's head is imaged every one or two seconds, producing a few hundred to a few thousand complete images per scanning session

Final takeaways

• Brain is “buggy”, evolution has had less time to shape rational decision making

• There is a “swiss army of tools” in the brain• Good decisions need to make use of these tools

(emotion, reason, meta-cognition)– How we think depends on what we are thinking upon