Lie detection: Cognitive Processes

How do we make decisions when we are uncertain? In more real-world settings there is often a vast array of information available to guide the decision, from an understanding of the social situation, to prior beliefs and experience, to information available in the current environment. Yet much of the research into uncertain decision-making has typically studied the process by isolating it from this rich source of information that decision-makers usually have available to them. This thesis takes a different approach. To explore how decisions are made under uncertainty in more real-world settings, this thesis considers how raters decide if someone is lying or telling the truth. Because people are skilled liars, there is little information available to make a definitive decision. How do raters negotiate the ambiguous environment to reach a decision? Raters show a truth bias, which is to say they judge statements as truthful more often than they are so. Recent research has begun to consider dual process theories, suggesting there are two routes for processing information. They claim the truth bias results from an error-prone processing route, but that a more effortful and analytical processing route may overcome it. I will generate a set of testable hypotheses that arise from the dual process position and show that the theory does not stand up to the test. The truth bias can be better explained as resulting from a single process that attempts to make the most 3 informed guess despite being uncertain. To make the informed guess, raters come to rely on context-relevant information when the behaviour of the speaker is not sufficiently diagnostic. An adaptive decision maker position is advocated. I propose the truth bias is an emergent property of making the best guess. That is, in a different context where speakers may be expected to lie, a bias towards disbelieving should be seen. I argue context-dependency is key to understanding decision-making under uncertainty

A model of trust manipulation: exploiting communication mechanisms and authenticity cues to deceive

A crucial factor when successfully deceiving others is to instill trust in the receiver that the professed scenario and communication are genuine. In order to achieve this, deceivers often manipulate established norms and trust mechanisms to aid in their deception. This chapter explores the role of trust in deceptive communications and the different ways in which trust may be manipulated by deceivers to influence the judgments of message recipients. Following this analysis, we present an initial model of trust manipulation that brings all of these factors together to consider how elements of communication, such as building rapport and the use of authenticity cues, may be used to invoke trust in order to effectively deceive others