Trust is a psychological factor that can gate channels of communication, persuasion, and collaboration. Here, I offer an overview of some of the neural and psychological mechanisms involved in coding for trust and coding for distrust. Trust can be conceptualized as two types of functions. The first is a factor in a relationship with another agent that is often socially developed through one or more interactions. The second is as an individual perception that contributes to certainty or confidence in the face of uncertainty. My research relates to the latter, and how people use incomplete information to handle uncertain or ambiguous decisions. I will show how the relationship between information and feelings of certainty is important for persuasion, and can lead to both optimistic and pessimistic biases in individual decision-making.