Evaluating the effect of response scale resolution on confidence judgements: A Multiple Threshold Race model approach

We evaluate the metacognitive properties of confidence and how response scales of different resolution affect it. Specifically, we used the Multiple Threshold Race model (MTR; Reynolds et al., 2021) to understand the placement of confidence boundaries and how they change across scales of different resolutions. In two studies, we tested how accurate people's confidence judgements are on a simple perceptual task: participants were asked to evaluate whether there were more blue or orange dots in a dynamic cluster. To understand the impact of response scales, participants rate how confident they are about that judgement. We manipulated the scale resolution so that it had 3, 4, 5, 6, 11, or 21 levels, as well as included a scale with continuous resolution. We also manipulated the difficulty of the task as well as included a speed vs. accuracy manipulation (whether speedier or more accurate responses was encouraged). Results show that reaction times follow Hick’s law under standard conditions but violate the law under time pressure. Difficulty also affected participant responses: people were generally overconfident in high-difficulty conditions, but their overconfidence decreased as the resolution of the response scale increased. By modeling the data with the MTR model, we aim to understand the cognitive processes that constitute confidence judgements.