- Shea, Timothy Michael
- Advisor(s): Noelle, David C
The science of decision-making is dominated by tasks which constrain decisions to occur
in fixed intervals of time with minimal movement of the body or environment. While these
constraints have proven useful for understanding perceptual and response competition, they do
not reflect the natural temporal structure of decision-making. To understand how we make
decisions, we must understand how the environment, the body, and the brain interact in time.
The environment both affords and constrains choice. The body reifies choice through movement,
or the lack thereof. The brain maps the dynamics of the environment onto the dynamics of the
body. From the interactions between brain, body, and environment, decisions emerge. This poses
a challenge for understanding decision-making: does one fix the environment and body to study
the mechanisms of the brain? Ignore the body and brain to study the nature of the environment?
Or even cut away the brain and environment to study the movement of the body? The challenge
is how to ground an understanding of decisions without reducing the essential complexity of the
subject. Although no response to this challenge will be fully satisfying, in this dissertation I will
describe a variety of research spanning the disciplines of cognitive and computational
neuroscience, behavioral psychology, ecology, and artificial intelligence with the goal of
generating new insights into decision-making.
The research presented in this dissertation broadly falls under a perspective I refer to as
dynamic decisions. The dynamic decisions perspective is informed by the following two
observations. 1) The consequences of decisions often demand high accuracy, yet neural
processes tend to be fairly noisy. This is reflected by speed-accuracy tradeoffs for many kinds of
decisions, where longer delays reduce errors. Delaying or stopping undesirable actions is
therefore an essential component of accurate decision-making. 2) Decisions are reified through
actions of the body, rather than purely mental or neural commitments. Thus, the relationships
between decision alternatives and ongoing actions, or even simulated actions, of the body are an
important influence on decision-making. Given these two principles, I argue that the outcome of
a decision is determined by when the decision is executed, and the study of decision dynamics
offers viable routes to integrate environment, body, and brain.
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