Humans can often report a subjective sense of confidence in a decision before knowing its outcome. Such confidence judgements are positively correlated to accuracy in perceptual and memory tasks, but the strength of this relationship (known as metacognitive accuracy) differs across people and contexts. Computationally, confidence judgements are believed to relate to the strength of evidence favouring each option, but it has been suggested that confidence also captures information from other sources, such as response time. This thesis explores the pragmatics of confidence: what factors influence confidence judgements, how accurate confidence judgements are, and how they might influence future behaviour. Our knowledge of the antecedents of confidence is extended by this work in two ways, by introducing novel predictors of confidence and by increasing our understanding of well-known ones. I find that bilinguals have worse metacognitive accuracy than monolinguals. This bilingual deficiency in metacognitive accuracy cannot be explained by response time and stimulus strength, suggesting that there is at least one important predictor of confidence that remains unaccounted for. I introduce such a predictor in a new eye tracking correlate of confidence: Gaze-shift-frequency, the number of saccades between options, negatively predicts subsequent confidence in perceptual and value-based decisions. In the value domain, the total value of the options is shown to positively relate to confidence despite being negatively related to accuracy, the first such dissociation to be recorded, as far as I am aware. The dissertation extends our understanding of response time as a predictor of confidence by showing that it influences confidence more for judgements that are made after a choice, relative to those made simultaneously with the choice. This differential influence of response time explains the higher metacognitive accuracy of sequential confidence reports. I explore the consequences of confidence judgements in the context of value-based choice. Lower levels of confidence are associated with changes of mind when the same options recur in subsequent trials. To test whether these changes of mind are rational, I approximate choice accuracy in the value domain. I propose a novel method based on the transitivity of the full choice set, so that choices that violate the most transitive ordering of the items can be treated as errors. I find that participants who were more metacognitively accurate showed a decrease in transitivity violations over time. These results extend prior work linking confidence judgements to error correction in the perceptual domain.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:744724 |
| Date | January 2018 |
| Creators | Folke, Nils Erik Tomas |
| Contributors | Ruggeri, Kai ; De Martino, Benedetto |
| Publisher | University of Cambridge |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.repository.cam.ac.uk/handle/1810/274961 |
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