class #5 Flashcards
Describe an experiment for decisions under risk
BART: Balloon Analogue Risk Task (Thibaut’s experiment)
Participants who received the transcranial stimulation on the DLPFC were more risk-seeking and impulsive compared to the sham group.
The DLPFC, in the ‘No-Go’ circuit, is essential to adequately suppress impulsive and risk-taking behaviors.
Risk taking behaviors are associated with activity in the ventral striatum & nucleus accumbens and the VMPF
Describe delay discounting and its neural correlates
DELAY DISCOUNTING: Decisions in the distant future are generally made more rationally. Near-term decisions are generally made more irrationally.
GO PATHWAY: Medial areas of the VPF are more active when choosing rewards that are smaller and occur sooner
NO GO PATHWAY: Lateral, and more dorsal areas of the PF are more involved when choosing rewards that are larger and occur later
Describe individual differences in the way we deal with delay discounting decisions.
Present Hedonism (PH) and Future Orientation (FO).
- The higher the participants’ score on FO, the more patient they were in their choices
- The higher the participants’ scored on PH, the higher their discount rate
Neural correlates:
The more we are ‘willing’ to delay our rewards, the ‘denser’ the connections between the striatum and the dorsal and ventral lateral aspects of the prefrontal cortex.
The more we are impatient to get our reward sooner, the ‘denser’ the connections between the striatum and the limbic system + the medial aspects of the prefrontal cortex
Describe framing effects with experiment and neural correlates
Experimental manipulation where people imagine a scenario where a firemen has to choose between certainty and risk in the amount of saving people. This is either framed as a gain or loss but outcomes are the same! Yet people choose differently!
Amygdala activation is significantly higher when subjects decided to choose the Sure option in the Gain frame, and the Gambling option in the Loss frame
Results: The more engaged the VMPFC, the higher the ‘rationality index’ in this task.These subjects were less susceptible to the framing effect.
Describe prospect theory and its relation to the somatic marker hypothesis
concave function: risk aversion for gains
Convex function: risk-seeking for losses
Loss aversion: The negative effect of a loss is larger than the positive effect of a gain
Diminishing sensitivity: 100-200 is felt more than 900-1000 dollars.
The brain likely uses some form of ‘common currency’ (dopamine, which computes reward value) when comparing different options
THE SOMATIC MARKER HYPOTHESIS: We move away from disadvantageous options
because our emotional system is warning us about potential losses
Describe experiment to test PT and somatic marker hyp.
The Iowa Gambling Task: bad decks and good decks reward per card
Skin conductance results:
Healthy (control) participants showed elevated skin conductance responses (i.e., a sign of high stress) in anticipation of a potential large loss (i.e., bad decks)
The amygdala ‘codes’ for rewards and punishment: patients with an intact amygdala (including those with VMPFC damage) do show a meaningful skin conductance response following both gains and losses
One of the next ‘brain-relay’ within the circuit is the VMPFC: patients with lesions in this part of the brain are unable to generate anticipation of potential losses.
Describe the conflict between system 1 and system 2. Give an example.
Dual-process accounts propose that although participants attempt to reason logically in accordance with the instructions, the influence of prior beliefs is extremely difficult to suppress (inhibit), and effectively competes for control of the responses made.
System 1:
Works at an intuitive, non-conscious level
Uses parallel processing
Independent of intelligence and attention
System 2:
Works at an explicit, conscious level
Uses sequential (integrative) processing
Depends on intelligence and attention
The bat and ball problem: A bat and a ball together cost $1.10. The bat costs $1 more than the ball. How much does the ball cost? System 1 says 10 cents but System 2 says 5 cents.
Describe an experiment to test the conflict between system 1 and system 2
Experimental procedure: logical reasoning task using syllogisms!
Participants tested in fMRI scan; brain activation measured during the task (i.e., the belief-bias task). Asked whether the conclusion is correct or not.
Content congruent: In these trials, the truth value of the conclusion is consistent with the validity judgment.
Content incongruent: In these trials, the truth value of the conclusion conflicts with the validity of the argument.
To correct for intuitive response:
Our brain deactivates the Ventral (medial) Prefrontal Cortex (‘Go pathway’) AND And activates the Dorsolateral Prefrontal Cortex (‘No-Go pathway’)!
Ventromedial prefrontal cortex (VMPFC) System 1 (intuitive) Belief-based
Dorsolateral prefrontal cortex (DLPFC) System 2 (rational) Deductive reasoning.
