RESEARCH STATEMENT
Julia Haas
I. Dissertation Research
Why do people do things they know they shouldn’t do? For example, Euripides’ Medea
knows she must protect her children’s lives, but a desire to harm her husband leads her to
murder them instead (Euripides, 2008). Philosophers call this phenomenon ‘akrasia’ or
‘weakness of will,’ and typically rely on the common-sense notions of reason, intention, and
desire to explain why it occurs. My doctoral dissertation, “Weakness of Will: A Case Study
for Moral Philosophy and the Cognitive Neurosciences,” provides a naturalistic theory of
why agents act against their better judgment. Converging evidence from computer science,
psychology, and neuroscience indicates that the human brain employs three dissociable
mechanisms to make choices. The ‘Pavlovian’ mechanism corresponds to ‘hard-wired’
approach and withdrawal responses. ‘Goal-directed’ behaviors map out different options and
assess them in light of specific goals. ‘Habit-based’ behaviors learn the value of actions over
time and choose the most consistently valuable option. I argue that suboptimal interactions
between these three decision-making mechanisms generate two different categories of
weakness of will, which are etiologically but not psychologically distinguishable.
My dissertation project stands at the intersection of philosophical analysis and computational
neuroscience. Chapter 1 of the dissertation situates the problem and significance of
weakness of will in Western philosophy, suggesting that philosophers have generally adopted
one of two basic conceptions of decision-making and weakness of will: i) deductive or
syllogism-based accounts and ii) valuation-based accounts, where the latter focus on how the
mind attributes values to external objects and experiences. Chapter 2 analyzes the
traditionally more dominant deductive theories of practical reasoning and presents evidence
from cognitive psychology demonstrating that these theories fail to account for real-life
aspects of deliberation and choice. Chapter 3 considers how reinforcement learning in
computer science investigates optimal decision-making systems, focusing on the
computational models that characterize the Pavlovian, goal-directed, and habit-based
decision-making mechanisms. I argue that although weakness of will is traditionally
identified as a single phenomenon, it in fact consists of a suite of discrete behaviors that
include ‘habit-based’ and ‘Pavlovian’ categories of weakness of will. In ‘habit-based’
weakness of will, agents rely on familiar actions to navigate everyday situations, only to
realize in some cases that the circumstances have changed and their actions are no longer
appropriate. In ‘Pavlovian’ weakness of will, agents’ ‘hard-wired’ responses to threatening
stimuli limit their ability to contemplate alternative courses of action. Chapter 4 integrates
emerging behavioral and neurological evidence to demonstrate that the human brain
systematically employs these three decision-making mechanisms in actual deliberation. I
propose two sets of computational and behavioral/fMRI experiment to test my hypotheses
(see below). In Chapter 5, I contend that my pluralistic, empirically-informed approach to
weakness of will transforms philosophical debates about weakness of will in particular, and
the nature of practical reasoning more broadly construed.
A component of this research has been recognized as one of the top 25 poster abstracts at
the International Neuroethics Society 2013 Annual Meeting. My poster, “Revising Weakness
of Will,” critiqued the theory of ego depletion as an explanation of weakness of will and
outlined my own neurocomputational account. I am currently revising this presentation as a
target article for publication in Neuroethics. I will present a second poster, “A Valuation
Theory of Practical Reasoning and Weakness of Will,” which considers the debate regarding
weakness of will and rational action in the contemporary philosophy of action, at the
American Philosophical Association Pacific Division Annual Meeting in April 2014, before
revising it for publication in Philosophical Psychology in July 2014.
II. Immediate Research Goals
Following the completion of my PhD, I plan to continue my research into the computational
and psychological underpinnings of weakness of will. In January 2014, Peter Dayan, the
Director of the Gatsby Computational Neuroscience Unit at the University College London,
invited me to present a paper entitled “Recruiting Computational Neuroscience to Explain
Weakness of Will” to his research group and fellow colleagues. Working with Dr. Dayan and
post-doctoral researchers Andreas Hula and Molly Crockett, I was able to design two
avenues for advancing my doctoral research. The first line of research uses computer-based
modeling to test my hypotheses regarding the computational foundations of weakness of
will. The second line of research uses behavioral and neuroimaging data to complement my
computation-based hypotheses.
1. Computational Research
Building on my visit to the Gatsby Computational Neuroscience Unit, my immediate
research goal for Summer and Fall 2014 is to develop computational models simulating my
two proposed categories of weakness of will. Upon completing a two-week Neural
Engineering Object (Nengo) training program at The Centre for Theoretical Neuroscience at
the University of Waterloo in June 2014, I will use the Nengo software package to exhibit
the flow of currents in different, interconnected populations of neurons. The first model will
represent the neural circuits involved in the complementary habit-based and goal-directed
decision-making controllers. The second model will represent the neural circuits involved in
the conflicting Pavlovian and goal-directed decision-making systems. Based on my doctoral
research, I predict that my simulations will generate two behavioral patterns analogous to the
habit-based and Pavlovian categories of weakness of will.
2. Behavioral/Neuroimaging Research
My second line of research will analyze a behavioral and neuroimaging data set assembled by
Read Montague’s Computational Psychiatry & the Neuroscience of Social Behavior group at
the Wellcome Trust Center for Neuroimaging at the University College London. My general
objective will be to determine whether the group’s behavioral and neuroimaging data
complement my hypotheses regarding the computational mechanisms causing weakness of
will. Specifically, I propose to analyze the group’s data on participants’ responses to a
sequential investment task (Lohrenz et al. 2007), in which participants must learn to make
improved decisions over time. I hypothesize that incorporating an aversive, Pavlovian
stimulus into the investment task will elicit the Pavlovian type of weak-willed behavior.
III. 18-month Research Goals
Over the next 18 months, my goal will be to revise my dissertation as a book manuscript
entitled Explaining Weakness of Will. This would include writing up the supplementary
computational and neuroimaging research outlined above, as well as preparing an additional
chapter on the associated psychological mechanisms underlying weakness of will. This latter
chapter will focus on the theory of ‘intention-action gaps’ (Ajzen et al. 1985, Hooft et al
2005). Upon completing this project, in September 2015, I plan to join Molly Crockett’s
group at Jesus College, Oxford University as a Junior Research Fellow, examining the neural
underpinnings of decision-making.