“There is no hope unmingled with fear, and no fear unmingled with hope.” ― Spinoza
Interpersonal trust is of enduring interest because it presents a dilemma of choice which can bring great happiness but also deep disappointment. This dilemma can be mitigated, but not eliminated (Krueger et al., in press). If the uncertainty about what the trusted party will do – honor our trust or betray it – were completely removed, trust would not be necessary or even be defined. This is rarely the case, however, and further inquiries into the nature of trust are instructive.
The experimental trust game is designed to capture the essential dynamics of interpersonal trust. Let us briefly review this game. A trustor, let’s call him Atouf, has an endowment of, say, 100 dirham (the currency in Kenitra). Atouf can exit the game by doing nothing. If so, he will keep the endowment. This risk-averse strategy and its outcome are represented by the letter P, the “Penalty” for not trusting. If, however, Atouf invests the money by sending it to the trustee, let’s call him Basam, its value will increase thanks to the magic by which investments appreciate. Now Basam chooses between keeping all the money and thus betraying Atouf, and sharing the appreciated investment evenly. In the case of betrayal, Atouf ends up with nothing, an outcome represented by the letter S, for “Sucker.” If Basam is trustworthy and reciprocates, Atouf ends up with 200 dirham, a handy profit represented by the letter R for “Reward.” The image below shows these payoffs.
Notice that in this game, trust is not a unitary psychological construct. It can be broken down into two separate motives. On the one hand, there is the Hope that the trustee will reciprocate; on the other hand, there is the Fear that he might not. This distinction between a motive to pursue a success (the R outcome in the trust game) and the motive to avoid a failure (the S outcome) has long been recognized in the psychological literature, notably in the theory of achievement motivation (Atkinson & Litwin, 1960). In the trust game, this distinction has been overlooked – as best as I can tell – so far.
In other interpersonal games, researchers have asked which of the two motives plays a greater role in driving decisions. In the prisoner’s dilemma, Dawes et al. (1986) found that greed plays a greater role as a determinant of defection than does fear. Kim et al. (2018) reported similar results for the volunteer’s dilemma. The trust game is slightly different in the important regard that only the trustor, but not the trustee, makes a choice under uncertainty, and the trustor cannot sucker the other player; hence we refer to the motive to obtain the best outcome as Hope and not greed.
As shown in the image, Hope is quantified by the difference between the Reward outcome and the Penalty outcome, whereas Fear is quantified by the difference between the Penalty outcome and the Sucker’s outcome. When the degree of appreciation of the trustor’s investment is increased, both Hope and Fear increase, that is, they are perfectly confounded with each other. Hope and Fear are, as Spinoza put it, intermingled. This means we cannot know if Hope or Fear play differential roles in the trustor’s motivated choice. With the outcomes assigned in this game, Hope and Fear are in a state of balance, so that a trustor who is equally sensitive to both, will be in a state of ambivalent indecision.
To see if Hope and Fear have differential effects on trust, we need to experimentally vary Hope (R – P) and Fear (P – S) separately. The two images below show what this intervention might look like. The left panel shows a game in which the numerical size of Hope has been increased from 100 to 150, and the right panel shows a game in which the numerical size of Fear has been reduced from 100 to 50. The net result on trust is the same. Trust is now appealing with a prospective value of +50 dirham in both new variants of the game. Notice that the trustee’s outcomes are not listed, which simplifies the treatment. A full exploration, of course, would require the manipulation of the trustee’s outcomes as well.
It should be recognized that this proposed experiment is but a rough sketch. Hope and Fear are expressed only in terms of differences between outcomes, whereas in ordinary psychological experience, both are bound up with expectations, that is, with the subjective probabilities that various outcomes will occur.
Can we make predictions about the likely findings in such an experiment? Risk-averse individuals will favor the reduced-fear game because here, the worst possible outcome is still positive (50), whereas risk-tolerant individuals will prefer the increased-hope game because it offers the maximum gain. The grand outcome of the experimental comparison will depend on whether there are more risk-averse than risk-tolerant participants. Since research with other social dilemmas suggests that greed is stronger than fear, we can also speculate that Hope will carry the day in games of trust.
The image at the top of this essay shows the Chinese ideograph representing the concept of trust. This ideograph comprises two elements. The left vertical line refers to the concept of “person.” The complex on the right refers to the concept of “word.” The idea is that trust is placed in persons to keep their word. The typical experimental trust game does not involve promises of reciprocation made by the trustee. When such promises are made, both trust and trustworthiness are likely to increase (Dawes et al., 1986), but promises do not eliminate the dilemma. The Hope of trustworthiness may increase, but the sting of betrayal will be far worse, if betrayal should occur. That is, a promise may only affect the balance of probabilities and outcomes, but not affect much the subjective expected value of the game.
