The Somatic Marker Hypothesis: Human Emotions in Decision-Making Presented by Lin XiaoBrain and Creativity InstituteUniversity of Southern California Most of us are taught from early on that :-logical, rational calculation forms the basis of sound decisions.-Emotion has no IQ.-Emotion can only cloud the mind and interfere with good judgment. But what if we were wrong?!What if sound, rational decision making in fact depends on prior accurate emotional processing?I will make the case that:Decision-making is a process critically dependent on neural systems important for the processing of emotions. Conscious knowledge alone is not sufficient for making advantageous decisions. Emotion is not always beneficial to decision-making; sometimes it can be disruptive.A Brief HistoryPhineas Gage was a dynamite worker, and survived an explosion that blasted an iron-tamping bar through the front of his head.Before the accident, Phineas Gage was a man of normal intelligence, responsible, sociable, and popular among peers and friends.He survived this accident with normal intelligence, memory, speech, sensation, and movement. However, his behavior changed completely:He became irresponsible and untrustworthy.Impatient of restraint or advice when it conflicted with his desires.A Brief HistoryA Brief HistoryPatients with Ventral Medial/Orbital Prefrontal Cortex damaged Before brain damage: Normal intelligence. After the damage: Normal intelligence.But Difficulties making good decisions in real-life. Their choices are no longer advantageous, and are remarkably different from the kinds of choices they are known to make in the pre-morbid period:  Their decisions and actions often lead to losses of diverse order, including:-losses in financial status-bankruptcies.-losses in social standing-involvement with unscrupulous people.-Break-up of family and distancing from friends.Patients with Ventral Medial/Orbital Prefrontal Cortex damaged This particular class of patients presented a puzzling defect: difficult to explain their disturbances in terms of defects in knowledge, general intellectual compromise, language comprehension or expression, or in memory or attention. However, their ability to express emotion and to experience feelings in appropriate social situations becomes compromised. Along with normal intellect, these patients show: 1. Abnormalities in emotion and feeling. 2. Severe impairments in judgment and decision-making in real-life.Patients with Ventral Medial/Orbital Prefrontal Cortex damaged Especially this latter observation was what led Antonio R. Damasio to propose what has become an influential neural theory of decision-making, the Somatic Marker Hypothesis (SMH).  The central feature of this theory is that emotion-related signals (somatic markers) assist cognitive processes in implementing decisions.  A further aspect of this theory is that these somatic markers can be non-conscious: they can bias behavior even when a person is not really aware of them.Somatic Marker Hypothesis (SMH)Definitions:EMOTION as a collection of physiological changes in body and brain states triggered in response to an event: Some changes are non-perceptible to an external observer, e.g., heart rate, skin conductance, endocrine release.Some changes are perceptible to an external observer (e.g. skin color, body posture, facial expression). The signals generated by these changes towards the brain itself produce changes perceptible to the individual and are ultimately perceived as a FEELING .Emotion= What an outside observer can see, or at least can measure.Feeling= What the individual senses or subjectively reports.Somatic Marker Hypothesis (SMH)Testing the Somatic Marker Model:-The Iowa Gambling Task (IGT) paradigm for measuring decision-making.Iowa Gambling Task (IGT)Iowa Gambling Task (IGT)Iowa Gambling Task (IGT)DD Gain per Card $100 $1250 -$250$100 $1250 -$250$ 50 $250 +$250$ 50 $250 +$250AABBCC“Bad” Decks “Good” DecksLoss per 10 CardsNet per 10 Cards5 secOnset of Card SelectionANTICIPATORY SCR(Before Choice)REWARD/ PUNISHMENT SCR(After Choice)(a)(b)The Iowa Gambling Task (IGT)Skin Conductance Response (SCR)Bechara A, 19940 second 10 second 20 secondCard SelectionCard Selection Card SelectionR/P R/P R/PAnticipatory AnticipatoryDo these somatic (emotional) signals have to be conscious?No!1. Somatic signals may bias decisions covertly.2. Conscious knowledge alone is not sufficient for making advantageous decisions.Number ofChoicesFrom DecksAnticipatory SCR LevelSequence of Card SelectionControlsDid not ReachConceptualPeriodVMPCDid ReachConceptualPeriodBad DecksGood DecksBad DecksGood DecksKnowledge Level(a)(b)(c)A Diagrammatic Summary of the Results of Bechara et al. (1997) Study(d)(e) Anticipatory SCRs represent unconscious biases that are linked to prior experiences with reward and punishment. Deprived of these biases, conscious knowledge of what is right and what is wrong may become available. However, by itself, this conscious knowledge is not sufficient to ensure an advantageous behavior. Therefore, frontal patients may be fully aware of what is right and what is wrong, but they fail to act accordingly: These patients can say “the right thing”, but they do “the wrong thing”.Modulating Factors 1.Time: information conveying immediacy (e.g. getting a heart disease tomorrow) exerts a stronger influence on decisions than information conveying delayed/future outcomes (e.g. getting a heart disease 20 years from now). 2.Probability: people prefer a sure gain over a probabilistic one, or they avoid a sure loss and prefer a probabilistic one instead. 3.Tangibility: people have an easier time spending money on credit cards as opposed to spending real money.-ReflectiveOrbitofrontal /VentromedialSystemTimeimmediatedelayedFrequencyhigh lowMagnitudehigh lowRelationconcreteabstractTriggering somatic statesStrong Weak+--++-Summation:Strong dominates WeakFeedback:Net Positive or Negative Somatic StateImpulsiveAmygdala System+-Information conveying immediacy (near future), high probability (certainty), or tangibility engages more posterior VMPC, whereas information conveying delay (distant future), low probability, or abstractness engages more anterior VMPC cortices (Bechara, 2005).-ReflectiveOrbitofrontal /VentromedialSystemTimeimmediatedelayedFrequencyhigh lowMagnitudehigh lowRelationconcreteabstractTriggering somatic