Knowledge for the sake of knowledge: Understanding the relationship between curiosity, exploration, and reward

Curiosity has long been a topic of scientific interest, but it encompasses so many potential traits and behaviors that it has been difficult to precisely target the cognitive and neural mechanisms that drive it. Recent work has reinvigorated the scientific approach to this topic by shifting from trait-level questions to a neurobiological perspective that emphasizes behavior, exploration and information-seeking. By viewing information as a reward, this research has leveraged the extensive body of work on reward processing to understand curiosity as a type of intrinsically motivated, goal-directed behavior. However, this information-as-reward framework raises a host of new questions about how curiosity develops and how it drives learning. In this dissertation, I aimed to test this framework and to address a series of questions about how curiosity drives exploration, learning, and memory. Chapter 1 addresses the question of how curiosity changes across the adult lifespan and tests whether these changes mirror well-established declines in dopamine transmission and reward sensitivity. The first study in this chapter found that, rather than showing declines in curiosity, older adults in fact displayed behaviors that reflected increases in curiosity. They were more willing to wait for information than younger adults and were equally able to remember the information they learned. The second study sought to replicate these results and to examine their neural substrates using fMRI. This study found that older and younger adults displayed equal levels of curiosity and memory. Results from fMRI also showed similar effects for both age groups: increased activation in brain regions associated with reward processing, as well as semantic memory, was related to curiosity and to memory. Chapter 2 explored the other end of development and examined changes in curiosity from late childhood into early adulthood. In this study, we focused on two different conceptualizations of curiosity -- willingness to wait (as in Chapter 1) and also a new measure of exploratory visual behavior. Results showed increases in both waiting and visual exploration between childhood and adulthood. These changes in curiosity were also accompanied by improvements in memory. These findings, like those in Chapter 1, provide evidence against the hypothesis that curiosity declines with age, and also expands our understanding of how different measures of curiosity-driven behavior may relate to one another. Chapter 3 addresses a fundamental question about how to evaluate curiosity and how different forms of curiosity cluster together. Using a large online sample, we obtained two separate groups of measures: measures of curiosity-driven behaviors (willingness to wait, ratings of interest about specific questions, curiosity-related memory), and measures of curiosity as a trait. Additionally, we obtained measures of traits and behaviors though to be related to curiosity, including impulsivity, need for cognition and willingness to wait for monetary rewards. Results revealed that different aspects of curiosity-related behavior cluster together, and that while there was a relationship between self-report and behavioral measures, there were also more nuanced differences in the relationships between different behaviors. Overall, the results from these three lines of research advance our understanding of curiosity by examining the extent to which curiosity is similar to reward processing, testing how it changes across the lifespan, and comparing different types of curiosity. The findings also open up new questions about the influence of other cognitive processes on curiosity and suggest ways in which we can better study how curiosity drives exploration and learning