The Economic Reductionism and Trust (Ir)rationality - Trust Theory: A Socio-Cognitive and Computational Model - page 239

to trust this medical doctor, but I continue to be anxious and to focus on risks and worries, and
to be very pessimistic about the results'.
However, optimists are obviously more trustful and more open to trust . This is well predicted
and explained in our model. They are all for the 'non-impossible' (plausible) eventualities; so
they have better expectations; they perceive less risk or do not focus on risks and thus have a
lower acceptance/trust threshold; they ascribe to people a pro-social attitude, common values,
non-hostility; they appreciate the gains, what has been obtained, and do not focus on what
they 'didn't achieve', so they are positively confirmed in their optimism and trust-decision.

When Trust Is Irrational
As we have seen in Section 3.7 it is possible to distinguish between rational and irrational
trust. One particularly interesting case, also linked with the optimism concept, is the following
one, where we really have an irrational form of trust; even 'subjectively' irrational. Let's call
'anti-rational' trust a decision to trust while subjectively going against our evidences. This is
not a 'spontaneous' outcome of a trust evaluation and choice; this requires an act of will; it is
a decision against our evaluation. This is when we say: 'I have decided to trust him anyway,
although I know that

, although I'm sure he will betray me'.
This decision and attitude is quite remarkable because it violates the usual relation between
trust as attitude-evaluation ( e-T ) and trust as decision ( d-T ). The usual (and rational) relation
is that: since I e-trust Y enough , I (decide to) d-trust Y .AndifI d-T Y this means that I e-T Y .
On the contrary, when I take that attitude and force myself to trust Y , I do not really trust Y .
That is, I d-trust him, without really e-trusting him. These 'subjectively' not so rational trust
attitudes are not necessarily 'objectively' irrational and dysfunctional. As we said, optimism
can in fact be a self-fulfilling prophecy; it can influence the chances of success.
For example, as we said, even a decision to trust against evidence and beyond the current
level of evaluation and expectation, can be objectively rational just because X 's act of trusting
Y can influence Y 's trustworthiness, can increase the chances of success: Trust creates trust
(see Chapter 6).
If X takes into account such an influence of her attitude and decision on Y , and predicts and
calculates this effect (see Section 6.3.3. on the dynamic of trust) her decision will also become
'subjectively' rational, since her degree of e-trust and her certainty in expectation has been
increased. Moreover, the 'decision' to trust can 'locally' be irrational, but it could be part of a
more general or overall decision. In saying this, X should have some additional reason (goal)
beyond the delegated one. For example, X wants to publicly demonstrate courage, or persuade
someone to risk and invest (be a model), etc., and this higher goal also increases the need to
cover and compensate the (probable) loss on

...

τ . So at the global level the risky trust act is part

of a rational decision.

Trust Versus Faith

As we have repeatedly explained, we accept the idea that, sometimes, trust is subjectively
irrational, not based on justified evidences, not grounded (or going beyond evidences), or
that it is just feeling-based and intuitive (but, perhaps, grounded on analogy and experience).
However, we deny that trust is necessarily and by definition only this. There is also a trust