The Economic Reductionism and Trust (Ir)rationality - Trust Theory: A Socio-Cognitive and Computational Model - page 235

Extreme optimists and extreme pessimists have two opposite default assumptions and two
opposite views of the 'onus of proof': does the onus lie on the prosecution side or on the
defense side?
Given this (partial) characterization of optimism, when trust is not based on evidence it
is an 'optimistic' attitude, since it assumes a favorable unproved outcome. Is this attitude
necessarily counterproductive, too risky, or is it subjectively irrational? It seems that non-
optimistic people (the more depressed ones) have a better (more realistic) perception of
reality in some dimensions. For example, they have a more adequate (realistic) perception of
the probability of the positive/negative events, and of their own control over events. While
optimists would distort both the probability of favorable events, and the control they have on
them. If something like this is true, optimism should be a disadvantage, since a distorted view
of reality should lead to failures. However, a lot of studies on 'thinking positively' have shown
that in several circumstances and tasks optimists fare better and that an optimistic attitude is
an advantage (Scheier and Carver, 1985), (Scheier et al., 1986), (Taylor and Brown, 1988).
How can we explain such an apparent contradiction: a distorted view of the world being more
adaptive? We will answer this in the following paragraph.

Trust and Distrust as a Self-Fulfilling Prophecy

In sum, if the trustee knows that X trusts him so seriously that she is relying on him and
exposing herself to risks - as we have explained - he can, for various reasons, become more
reliable and even more capable, that is, more trustworthy. This is due to different possible
psychological processes (Chapter 5).
The fact that X appreciates Y , has esteem for him, can make Y more proud and sure in his
actions. He can either feel more confident, can increase his self-esteem or determination. Or
Y can feel some sort of impulse in reciprocating this positive attitude (Cialdini, 2001). Or he
can feel more responsible and obliged not to disappoint X 's expectation and not to betray her
trust. He would bring harm to X, which would be unfair and unmotivated. In other words,
X 's perceived trust in Y can both affect Y 's motivation (making him more reliable, willing,
persistent,..) or his effort and competence (attention, carefulness, investments, ... ) (see also

Section 8.6 on Reciprocity).
Given this peculiar dynamic of trust one may say that trust can in fact be a self-fulfilling
prophecy. Trust in fact is - as we know- an expectation, that is, a prediction. However, this
(optimistic) prediction is not just the evaluation of an apriori probability that is independent
and indifferent to the subject evaluation.
If X plays the roulette game and feels sure and trustful about the fact that the next result will
be 'Red', this doesn't have any affect on the probability (50%) of it being Red. But there are
a lot of 'games' in human life that are not like roulette, and where an optimistic attitude can
actually help.
Consider, for example, courting a woman, or competing with another guy, or preparing for
an exam; in this kind of 'game' the probability of success is not predetermined and independent
from the participant's attitude and expectations. Self-esteem, self-confidence, trust, etc. that is,
positive expectations, make the agent more determined, more persistent, less prone to give up;
and also more keen to invest in terms of effort and resources. This does change the probability
of its success. Moreover, a positive, confident and self-confident attitude as perceived by the