Socio-Cognitive Model of Trust: Quantitative Aspects - Trust Theory: A Socio-Cognitive and Computational Model - page 90

no real definition and cognitive characterization of trust is given; so, the quantification of trust
is quite ad hoc and arbitrary, and the introduction of this notion or predicate results in being
semantically empty. 1
On the contrary, in our studies we try to understand and define the relationships between
the cognitive definition of trust, its mental ingredients, and, on the one hand, its value. On the
other hand, its social functions and its affective aspects (Chapter 5). More precisely the latter
are based on the former.
In this chapter we will show our efforts to ground the degree of trust of X in Y in the cognitive
components of X 's mental state of trust. 2 In particular, given our belief and evaluation based
model, we predict and claim that the degree of trust is a function:

on the one hand, of the estimated degree of the ascribed 'quality' of Y on which the positive
expectation is based;
on the other hand, it is a function of the subjective certainty of the pertinent beliefs.

Let us be more specific: the first component describes the quantitative level of Y 's quality under
analysis: for example, if X is evaluating Y 's ability (about a given task ) she has to select

among different discrete or continuous values the one (or ones) she considers the more adequate
to attribute to Y . These values could be either directly numerical or described by linguistic
categories referable to a set of numerical attributions ('very good', 'good', 'sufficient', 'poor',
just to give some examples). X could have, for example, a main (prevalent) belief that Y is
either with ability 0.7 or 0.8 (in the scale (0,1)) and a secondary (less relevant) belief that Y is
not so able (ability included in the 0.2-0.3 interval). See Figure 3.1 as an example.
At the same time, X also has a meta-belief, 3 about the subjective certainty of these beliefs
(the second component indicated above): how much is X sure of her evalutative beliefs about
Y 's quality?
These meta-beliefs in fact translate the strength of the reasons that produced the first-level
beliefs. Are they based on a consistent (or just superficial) set of experiences, reasoning,
facts, deductions, a priori judgments, and so on? There is, of course, a correlation between
the construction of the first kind of belief and the building of the second kind, but we can
distinguish (and it is useful to do this for analytical reasons) between the different semantic
and functional roles of the two categories. In any case, for simplicity, in the following part of
the chapter we will consider the integration of beliefs and meta-beliefs.
We will use the degree of trust to formalize a rational basis for the decision of relying and
betting on Y . We will also consider - for the 'decision' to trust - the quantitative aspect of
another basic cognitive ingredient: the value or importance or utility of the goal g X .
As we said, trust always implies risks, and frequently 'perceived' (evaluated) risks (Sec-
tion 2.8.2). So we will also introduce the evaluation of the risk (depending on the potential

τ

1 As reported also in other parts of this topic Williamson (Williamson, 1993) claims that 'trust' is an empty and
superfluous notion - used by sociologists jn a rhetorical way - since it is simply reducible to subjective probability/risk
(Chapter 8).
2 Precisely the 'affective' trust in part represents an exception to that; since its 'degree' is not based on arguable
'reasons' but it is due to the 'intensity' of the feeling or of the evocated 'somatic markers'.
3 An 'explicit' belief about other beliefs, or an 'implicit' one; that is, just some index of the belief strength or
certainty; like the one we have introduced in the analysis of 'expectations' and of their 'strength' (Chapter 2).