Probabilistic and Dynamical Models of Belief Update: Effects of Experimentally Induced Implicit Bias

Organisms undertake actions on the basis of perceptions. Perceptions serve as the basis for what an agent takes to be the case; that is, for the agent’s beliefs. However, the idea of belief is freighted with notions of fallibility and subjectivity, since belief is often considered insofar as it is distinct from knowledge. Here, an attempt is made to link belief more closely with perception and action. This linkage is shown by considering the role belief plays in determining behavior, which is distinct from the role belief plays in language-based philosophical accounts of content and intention. These two notions of belief, and the separation between them, are the subjects of four experiments in which a method of introducing bias in participant responses is employed. In a perceptual task based on the Asch line-length judgment paradigm, participants showed a propensity to respond in keeping with the induced bias rather than with stimulus properties. In a cognitive task based on the Monty Hall Dilemma, participants’ responses were consistent with the induced bias but were less consistent with the best MHD strategy. Experiment 1 established the line-length methodology, which was extended in Experiment 2. Experiment 3 employed the MHD paradigm. Experiment 4 brought the current line-length paradigm into closer contact with the classic Asch paradigm. The overall results were consistent with the claim that belief-as-action and belief-as-assent can, theoretically and methodologically, be treated separately