B&C - Decisionmaking

Satisficing heuristic

You choose the first option that meets your criteria

Anchoring heuristic

Occurs when you focus on one piece of information when making a decision or solving a problem.

Diminishing marginal utility

A small increase in utility will not make you significantly more happy when you already have a lot of utility. The more you have, the more you need

Framing effects (brain part)

You actually do a risky choice in a loss frame and a safe choice in a gain frame.

Dorsomedial prefrontal cortex involved in this decisionmaking

Prospect theory

Losing is harder than winning. 2 aspects:

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1. Reference points
2. People are not entirely rational. What causes less loss is often chosen more frequently

Endowment effect

People ask a higher price for something they own than they are willing to pay in order to buy it

Reward systems

* Ventral tegmental area (VTA)
* Nucleus accumbens (part of ventral striatum)
* Rest of brain
* All use dopamine as neurotransmitter!

VTA (ventral tegmental area) projects to…?

* Nucleus accumbens
* Amygdalae
* Hippocampus
* Medial parts of prefrontal cortex

Where can drugs be linked to regarding rewarding?

Virtually all drugs can be linked to change dopamine activity in the reward circuit

NA in humans is more active when…

Unexpected reinforcement takes place.

Intrinsic motivation

You do it because you like to do it.

Extrinsic motivation

You do it because you get something.

Reward undermining experiment

1. Participants played a game in which they had to stop a timer at exactly 5 minutes.
2. Half of the participants received a reward during the first session only, while the other half did not get a reward.

Finding: activation in the ventral striatum dissapeared in session 2 in people who were rewarded first. → loss of motivation

What information do dopamine neurons encode?

It’s not about the reward itself, but about how to get it.

Monkey motivation paradigm

1. Monkeys with an electrode in the VTA record single neuron activity
2. Monkeys are learned to press a pedal to get juice


1. Operant conditioning!
3. Then only when a light came on monkeys got the juice


1. Discrimination training

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Finding:

First trials, increased VTA response at reward.

Later increased VTA response at cue.

In the absence of the reward, dip in VTA response.

Reward prediction errors

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As long as our predictions meet our experiences = nothing

But, when something happens we do not expect, we become alert.

VTA activation is larger when a prediction is false

Unexpected rewards trigger…

ACC

Effects of rewards can be seen…

Throughout the whole brain

Risk (meaning & brain part)

The estimated variance in possible outcomes

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Prefrontal cortex:

* Dorsolateral and dorsomedial prefrontal cortex
* Posterior parietal lobe
* Anterior part of insula

More activity in anterior insula when….

confronted with standard economic decisions and gain/loss anticipation

* Monitoring of aversive signals & away from risky options

More activity in dorsomedial prefrontal cortex when…

confronted with limited information about what decisions should be made

If you do not know the probability of an outcome, a decision involves …

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More activity in ….

Ambiguity, dorsolateral prefrontal cortex → more control is needed

Uncertainty due to delay

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Temporal discounting

When you have to wait for the reward.

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The further in the future, the less the same reward will be worth. Reversed for choices in far future

Dual system model

1. System 1: fast, parallel, automatic, context-dependent and emotionally controlled
* ventral stratium and medial prefrontal cortex and posterior cingulate cortex
2. System 2: slower, serial, cognitively controlled (cost-benefit analyses)
* lateral prefrontal cortex (makes sense: the more lateral the more involved in higher functions)

Social reward monkey experiment

1. Monkeys looked at a fixation point, after this they got presented with two targets.
2. If monkey looked at target T1, they got juice.
3. If monkey looked at target T2, they got juice + an image to look at.
4. Experimenters could manipulate the amount of juice for both T1 and T2 outcomes.
5. Worth of images can be expressed in the amount of juice

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Finding: Male monkeys wanted to pay to look at certain pictures. They had to perceive payment to look at other pictures.

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Payment for: Gray squares and low-ranking monkeys

Less payment: High-ranking monkeys and female mating displays

In humans, attractive faces activate…

ventral striatum

ventromedial prefrontal cortex

Prosocial behavior correlates with activity in…

ventral striatum

* a warm glow

also in network involved in social cognition

* i.e. regions for perspective taking (superior temporal sulcus) and and medial PFC

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Social cooperation (why, brain parts)

Why?

* Self interest, interest in the group, altruism
* Nucleus accumbens (& caudate nucleus)

Iterative prisoners dilemma

* Consistent cooperation is the best strategy, leading to more confindence and more profit in the future

Cooperation itself correlated with increased activity in…

Nucleus accumbens

Reciprocity

When you give something, you get something back.

Caudate nucleus related to

trust

Ultimatum games

Research the role of fairness

Unfair offers relate to activation in…

Insula

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The more unfair the more activity in insula

Altruistic punishment

Punishing others for violating social norms, even at the cost of your own benefit!

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Activation of ventral striatum (including NA)