Lecture 7

Question 1

Which psychological systems are involved in trust and which brain networks do they engage? What is the role of each of these systems?

Answer 1

Affective system engages salience network to incorporate aversive feelings associated with risk of treachery by another person.
Motivational system involves reward network to determine the anticipated reward for trusting another person.
Cognitive system involves central-executive network to adopt context-based strategies for trusting a partner and default-mode network to evaluate relationship-based trustworthiness of a partner.

Question 2

Which regions are part of the Salience network?

Answer 2

Amygdala, insula, dACC

Question 3

What is the role of the amygdala?

Answer 3

It uses automatic, emotional processing to evaluate incoming social information. Positive evaluations will enhance trust, while negative evaluations will result in distrust.

Question 4

What is the relationship between activation in the amygdala and face trustworthiness? What if the amygdala is damaged?

Answer 4

The amygdala plays a key role in decisions of trustworthiness based on facial appearance, especially for faces that are normally classified as untrustworthy. The less trustworthy a face, the more active the amygdala as it responds to averse simulations.
In the case of a damaged amygdala, one is unable to process negative faces well, which is why they will assess them as more positive overall.

Question 5

What are the effects of a damaged amygdala in a trust game?

Answer 5

Patients display increased benevolent behaviour. Others increase trust in response to betrayal, whilst amygdala damaged patients will use the benevolent strategy of increasing the amount, if the others do not change.

Question 6

What is the damaged amygdala’s result on trust? How does the BLA influence that?

Answer 6

Amygdala damage results in maladaptive social behaviour due to lack of appropriate and accurate evaluation of social situations and social partners. If you can’t assess the trustworthiness of the other, you can’t adapt your behaviour.
Specific (basolateral) part of the amygdala is crucial in learning from the interactions with the social environment. Damage to BLA causes one to rely on primary impulsive responses to help and cooperate.

Question 7

What is the role of the insula?

Answer 7

It encodes subjective and aversive feelings of unpredictable events evoked by the risk of betrayal while trusting a partner.

Question 8

How did the insula behave in the trust game?

Answer 8

The insula behaved in two different ways, benevolently and malevolently. The insula recognises risk during decision-making and identifies social norm violations.

Question 9

How did the insula behave during the one-shot trust game with a human counterpart or a computer mediator?

Answer 9

Insula reflects heightened negative state associated with betrayal aversion, since trusting a human is safer than a robot. Hence, insular activity is an aversive signal warning to avoid future negative emotions.

Question 10

What is the role of the dACC?

Answer 10

The dorsal anterior cingulate cortex is associated with cognitive and emotional conflict processing and resolving.

Question 11

How did the dACC act during the trust game with an antecedent promise stage.

Answer 11

Dishonest subjects showed increased activation in the dACC because they might have already known that they will break the promise of reciprocating.

Question 12

Which regions are part of the Reward network?

Answer 12

vSTR, dSTR, vmPFC

Question 13

What is the role of the vSTR?

Answer 13

The ventral striatum regulates motivation for rewarding stimuli by predicting and anticipating the outcome of an interaction. It encodes anticipation of reward via error prediction based on differences between expected and observed reward.

Question 14

How did the vSTR behave during the iterative trust game with partners developing different reciprocity reputations?

Answer 14

Activity in ventral striatum represents a signal for actual reciprocity. Hence, it selectively encodes the value of gains from trustworthy partners (based on real-time interactions), anticipated reward.

Question 15

How did the vSTR behave during the iterative trust game with partners with different moral character descriptions?

Answer 15

Ventral striatum activity in the decision phase predicted and anticipated the outcome of risky decisions.

Question 16

What is the role of the dSTR?

Answer 16

The dorsal striatum processes feedback information related to the likelihood of others’ continued cooperative behaviour. Hence belief updates about a partner’s behaviour

Question 17

How did the dSTR behave during the iterative trust game with partners with different moral character descriptions?

Answer 17

Activity in trial and error learning about reciprocity through processing feedback.

Question 18

What is the role of the vmPFC?

Answer 18

It represents an interface between emotional and motivational processes.
It encodes the expected utility/ social value of stimuli and it computes the worth/value of current social state.

Question 19

How did the vmPFC behave during the trust game? Does damage influence its behaviour?

Answer 19

This region is involved in betrayal aversion and sensitivity to guilt, though vmPFC damage leads to lack of betrayal aversion and insensitivity to guilt. This region is involved in valuing social information. Therefore, if damaged we have an incapacity to value social information.

Question 20

How did the vmPFC behave when it was put through tdcs?

Answer 20

Excitation of the vmPFC leads to more repayment in the trust game. Hence, there is a critical role of the vmPFC in cooperative behaviours in economic interactions.

Question 21

Which regions are part of the Central executive network?

Answer 21

dlPFC, vlPFC

Question 22

What is the role of the dlPFC?

Answer 22

It removes uncertainty by accounting evidence contextually. It uses a rule-based selection of responses (being selfish or not) and updates expectation of rewards. Hence, it modulates the relative impact of prosocial motives and self-interest goals. Nevertheless, it enhances goal-directed behaviour and improves long-term outcome.

Question 23

What are the age effects in the trust game for the dlPFC?

Answer 23

The older, the more activation in the dlPFC when investing in cooperative partners. Hence, individuals increasingly consider higher order social rules when making decisions. The dlPFC deals with impulse control to resist immediate urges to realise greater cooperative benefits at a later time.

Question 24

What is the role of the vlPFC?

Answer 24

It removes and eliminates uncertainty by discounting evidence contextually. It inhibits information about the social risk to maintain a positively biassed expectation of a partner’s reciprocity.

Question 25

How does the vlPFC behave in the trust game with prior information on the reputation of the other partner?

Answer 25

The vlPFC contributes to maintaining choices aligned with reliable prior beliefs, when beliefs momentarily conflict with observation. Hence, favours social stability.

Question 26

Which regions are part of the Default mode network?

Answer 26

TPJ, dmPFC

Question 27

What is the role of the TPJ.

Answer 27

The temporo-parietal junction infers and attributes intentions of others on the perceptual level (implicit evaluation) to assess trustworthiness

Question 28

What is the role of the TPJ.

Answer 28

The temporo-parietal junction infers and attributes intentions of others on the perceptual level (implicit evaluation) to assess trustworthiness.

Question 29

What are the age effects of the TPJ in the trust game?

Answer 29

It showed an increased engagement of left TPJ with age, as there is a shift in attention from the self to the world during the stages of life.

Question 30

What is the role of the dmPFC?

Answer 30

It infers and attributes traits of others on a more abstract cognitive level.
It evaluates partner’s trustworthiness also based on priors, conveying information about the social characteristics of partners (explicit evaluation).

Question 31

How does the dmPFC behave in a trust game with prior information on the partner’s reputation?

Answer 31

The dmPFC encodes reputational priors with the first presentation of the counterpart. Hence, the role of the dmPFC is to ascribe attitudes to others and to anticipate their choices.