Socio-Cognitive Model of Trust: Quantitative Aspects - Trust Theory: A Socio-Cognitive and Computational Model - page 96

Resuming the trustor's mental state we have two main subsets:

(a) A set of mental states ( MS-CT X,Y ) -called Core Trust - with these components:
- a set of X's goals and, in particular, one specific of them ( g X ) in order to trust Y ;
- a set of X's competence beliefs ( B-Com X,Y )on Y about

τ ;

- a set of X's disposition beliefs ( B-Dis X,Y )on Y about

and
- a set of X's practical opportunities beliefs (B-PrOp X,Y )on Y about

τ

τ at that given

moment (time) and site (space).
(b) A set of mental states ( MS-REL X,Y ) -called Reliance - that must be added to the 'core trust'
ones and that are strictly linked with the decision to trust; in particular:
- a set of X's dependence beliefs (B-Dep X,Y ) (it is needed or it is better to delegate than
not delegate to Y ((Sichman et al. , 1994), (Jennings, 1993)) and
- a set of X's preference beliefs ( B-Pref X,Y ) for delegating to Y (in fact, although this
notion is related to the dependence notion, we like to mark it).

We can imagine that each one of the above listed beliefs will have a specific value.
In order that X trusts Y about τ , and thus delegates that task to Y , it is not only nec-

essary that the DoT XY τ ),

but also that it constitutes the best solution (compared with other possible and practicable
solutions).
In any circumstance, an agent X endowed with a given goal, has three main choices: 9

exceeds a given threshold (depending on X, Y and the task τ

i) to try to achieve the goal by itself;
ii) to delegate the achievement of that goal to another agent Y ;
iii) to do nothing (relative to this goal).

So we should consider the following abstract scenario (Figure 3.4)
where we call:

U(X) , the agent X 's utility function, and specifically:

U(X) p + , the utility of X 's success performance (directly realized by agent X );
U(X) p − , the utility of X 's failure performance (directly realized by agent X );
U(X) d + , the utility of a successful delegation (utility due to the success of the
delegated action to Y );

U(X) d − the utility of a failure delegation (damage due to the failure of the delegated
action to Y );

U(X) 0 the utility of doing nothing.

9 The choice of collaborating on a given goal implies the agreed delegation of a subgoal (of a subpart of the main
goal) to Y : that means to apply the choice number (ii).