Darko Odic

The human mind represents information in many domains and formats. Perceptual representations of number, space, and time integrate into a holistic conscious experience, while abstract representations (e.g., morality, justice, meaning, etc.) shape our collaborative and individual behaviours. To accomplish this, perceptual and non-perceptual representations must interface, allowing us to use abstractions to describe our perception, and using perceptual experience to help us choose specific instances of potentially infinite categories. What mechanism supports the interface between perceptual experiences, especially those which are universally shared across human and non-human animals alike, and language, a distinctly human psychological phenomenon? To explore this puzzle, I focus on one case study in particular: the link between number words and perceptual magnitudes (e.g., number, space, time). Across 5 studies and distinct developmental groups (e.g., children, adults), I examine (1) what supports the acquisition of the logical, generative interface that underlies this link (Chapter 2), (2) how this interface can be extended once it’s acquired (Chapter 3) and (3) what the representational format is that allows number words to be linked to perceptual magnitudes in the first place (Chapter 4 & Chapter 5).This dissertation provides several insights into how the human mind integrates perceptual and non-perceptual formats. I demonstrate that once this interface is achieved between number words and one perceptual magnitude (i.e., number) early in development, it can be logically and flexibly extended across perceptual experiences, including to different units (e.g., labelling a set of 3 dots as “one”; Chapter 3) and magnitudes (e.g., length: judging that a line is “eight” units long; Chapter 2). Then, by exploring differences in how this interface is implemented across numeric vs. non-numeric magnitudes (Chapter 4), I get at the very format of perceptual representations, themselves (Chapter 5).Understanding how this interface is achieved is not only important for getting at the broader relationship between language and perception but is even more important from the perspective of development. Children have access to perceptual magnitude representations from birth but slowly acquire culturally-specific tools for reasoning about these magnitudes in abstract ways (e.g., number words, measurement units, mathematics, etc.).

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In a noisy world filled with confusion, humans need a toolkit of skills to help discern fact from fiction. In this dissertation, I explore one such tool and its development in childhood: metacognitive reasoning about confidence. In 7 studies, I investigate how children reason about the strength of subjective information, uncovering the properties of childhood metacognition and using its development as a tool to learn about metacognition more broadly.Fueling this research are two families of theoretical accounts: one which conceptualizes confidence as a direct readout of decision noise (Direct accounts), and one where confidence is a combination of information from multiple sources (Inferential accounts). These two accounts make divergent predictions about two properties of metacognition: (1) how tightly bound confidence is to the underlying decisions it evaluates, and (2) how broadly is confidence represented in the mind. I investigate these questions using a developmental lens for testing between these theories.These studies present a force-choice method of measuring children’s sensitivity to confidence by asking how closely they can tell apart two states of confidence. This method of assessing confidence allows me to narrow in on the properties of metacognition that develop independently of children’s overconfidence biases and developing linguistic knowledge. In Chapter 2, I use this measure to look for developmental change associated with confidence judgments when controlling for decision noise, finding age-related change consistent with the Inferential accounts. In Chapter 3, I test whether children reason about confidence using encapsulated systems or a broader metacognitive system, and probe whether these judgments share a unit of representation, finding evidence for both within the domain of perceptual judgments as predicted again by Inferential accounts. In Chapter 4, I investigate whether confidence is processed so broadly as to include reasoning about others’ abilities, but do not find strong evidence of this, suggesting a limit on the generality of confidence processing.All together, this dissertation shows that far from being subject to the whims of others, children possess a sense of confidence that combines multiple sources in information to create broadly-usable assessments of truth in the world.

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Our ability to reason about the perspectives of others is associated with many positive life outcomes (e.g., better interpersonal relationships). Unfortunately, when reasoning about the perspectives of others, we are often biased by our own knowledge (i.e., the curse of knowledge). The curse of knowledge is a cognitive bias that limits our ability to reason about less- knowledgeable perspectives. It leads to overestimations of what others know and clouds our judgements about their beliefs. Critically, this bias is prevalent across various contexts, and it affects our social reasoning across the lifespan. Previous research demonstrated the effects of the bias on children’s social reasoning, however there are several critical theoretical questions that remain unanswered. For instance, is the bias universal among children? I find support for the universality of the bias, in Chapter 2, by showing that even children of a nomadic pastoralist tribe, the Turkana, show the bias. Furthermore, in Chapter 3, I examine how age-related changes in the bias can affect young children’s performance on a widely used measure of Theory of Mind—a false belief task. I examine this question in two experiments; one showing that younger children are more accurate at reasoning about other perspectives when the curse of knowledge is minimized. The other experiment showing that children’s inferences are biased by their knowledge but that minimizing the bias does not improve performance. I discuss potential reasons for the discrepancy between experiments. Finally, I examine two accounts on the mechanisms underlying the curse of knowledge. In Chapter 4, I provide evidence that fluency misattribution (i.e., the tendency to attribute the fluency in processing a stimulus to an inaccurate source) is necessary for the bias to occur. Chapter 5 summarizes my findings, discusses their implications, and highlights avenues for future research.

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