Appearing suspicious may come at a cost

Suspicion by Gültekin Bilge

How do you trust others? What makes you become suspicious when working with other people? Though we rely on collecting information about others when making decisions, the ways we collect that information may change how others perceive us. People may be less likely to trust others when they inquire about their behavior in a way that appears suspicious, a new study shows.

Decisions of whether to trust other people can vary based on risk and uncertainty. In simulating how people trust one another using a game between trustees and investors, researchers studied social context, monetary cost, and the trustee’s trustworthiness to show that an investor appearing suspicious may lessen trust and appearing averse to betrayal, increase trust.

Using computational models of how individuals collecting information before making an investment decision, the researchers examined the intuitive patterns behind why participants made the decisions they did. They tested participants under conditions of whether collecting information cost money and whether the trustee would know the investor was collecting information. Participants gathered less information when it came at a cost and when they could find conclusive results from the information about others.

The researchers tested various model to determine which one fit the experimental results best. When the difference between outcomes that would favor investing was different enough from those that wouldn’t, participants stopped collecting information. To test how strong of a role suspicion played in these decisions, they compared the Cost of Appearing Suspicious (CAS) model against a Sample Cost model, an Uncertainty model, and a discrete Drift Duffusion Model (dDDM). For the CAS, Sample Cost, and Uncertainty models, the participants’ decisions are Bayesian in the sense they determined how likely they are to invest based on their previous beliefs about either the trustee or the investor.

The CAS model used a suspicion factor, that gathering information decreases the probability of investment. The Sample Cost model does not use this suspicion factor, and, under the Uncertainty model, participants would stop when the posterior belief distribution width dropped below a tolerance threshold. Under the dDDM, on the other hand, participants would collect information until their evidence for trustworthiness or untrustworthiness met a certain criteria. After determining how well models fit various conditions on the individual level, they found the CAS model predicted better than the others, and it even fit well to investment decisions after collecting information.

When individuals choose to invest or not, scientists have proposed various models for decision-making across different contexts. They come into play as people choose whether to work with or trust others. One study in the Proceedings of the National Academy of Sciences showed, when people work together, they care about whether their partner gathers information about how much they would profit if they defected. They instead engage in blind cooperation cooperate among trustworthy and untrustworthy people, but don’t collect information to make themselves appear suspicious. This is further shown that people are perceived as selfish when they gather information for their own profit in a study in the Journal of Behavioral and Experimental Economics.

The work has practical applications in information collection and use for psychiatric disorders. Biases in collecting information when information is uncertain or scarce has been associated with weighing negative information heavily in depression and compulsivity. How well we model the moral character of other individuals are central to disorders like borderline personality disorder and autism.