Sure or unsure: How is confidence in perceptual decisions generated?

• Applicants: Manuel Rausch, Ph.D.; Professor Dr. Michael Zehetleitner
• Subject Area: General, Cognitive and Mathematical Psychology
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 414076635

Human observers are frequently faced with the need to respond to external objects although perception of these objects is incomplete or distorted. In these cases, it is necessary to use the percept of the object to make a decision which of several possible objects is present at the moment. In general terms, these decisions are characterized by three properties: First, humans can make a correct or an incorrect decision which of the objects is present. Second, it may take varying periods of time until a decision is accomplished. Finally, humans may feel a greater or lesser degree of confidence about having made the correct decision about the object. However, the existing mathematical theories of decision-making are not able to provide a satisfactory explanation for accuracy, decision time, and confidence at the same time: Our preparatory studies suggested that confidence in incorrect decisions increases with the physical quality of stimulation, which is an observation that cannot be reconciled with any of the existing theories. At a consequence, the goal of the present project is to provide a mathematical theory of choice, confidence, and decision time. For this purpose, we plan to extend a theory we proposed earlier, the weighed evidence and visibility model, in the temporal domain. The main idea is that a decision is made by accumulating sensory evidence about the identity of the object until a decision threshold is reached. Confidence is generated from two inputs, including the sensory evidence about the identity of the object, as well as sensory evidence about the physical quality of stimulation. The main purpose of the present project is to test this new dynamical version of the weighed evidence and visibility model, which is why an independent sample of participants, extended mathematical modelling, as well as a series of control experiments are required. As a second step of the project, we aim to investigate the consequences of that theory for research fields that use confidence ratings to measure observers’ ability to differentiate between different stimuli.

• DFG Programme: Research Grants