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Nathaniel Daw

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https://www.readbyqxmd.com/read/28653668/reminders-of-past-choices-bias-decisions-for-reward-in-humans
#1
Aaron M Bornstein, Mel W Khaw, Daphna Shohamy, Nathaniel D Daw
We provide evidence that decisions are made by consulting memories for individual past experiences, and that this process can be biased in favour of past choices using incidental reminders. First, in a standard rewarded choice task, we show that a model that estimates value at decision-time using individual samples of past outcomes fits choices and decision-related neural activity better than a canonical incremental learning model. In a second experiment, we bias this sampling process by incidentally reminding participants of individual past decisions...
June 27, 2017: Nature Communications
https://www.readbyqxmd.com/read/28483979/chronic-and-acute-stress-promote-overexploitation-in-serial-decision-making
#2
Jennifer K Lenow, Sara M Constantino, Nathaniel D Daw, Elizabeth A Phelps
Many decisions that humans make resemble foraging problems in which a currently available, known option must be weighed against an unknown alternative option. In such foraging decisions, the quality of the overall environment can be used as a proxy for estimating the value of future unknown options against which current prospects are compared. We hypothesized that such foraging-like decisions would be characteristically sensitive to stress, a physiological response that tracks biologically relevant changes in environmental context...
June 7, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28298555/low-lifetime-stress-exposure-is-associated-with-reduced-stimulus-response-memory
#3
Elizabeth V Goldfarb, Grant S Shields, Nathaniel D Daw, George M Slavich, Elizabeth A Phelps
Exposure to stress throughout life can cumulatively influence later health, even among young adults. The negative effects of high cumulative stress exposure are well-known, and a shift from episodic to stimulus-response memory has been proposed to underlie forms of psychopathology that are related to high lifetime stress. At the other extreme, effects of very low stress exposure are mixed, with some studies reporting that low stress leads to better outcomes, while others demonstrate that low stress is associated with diminished resilience and negative outcomes...
April 2017: Learning & Memory
https://www.readbyqxmd.com/read/28230848/computational-approaches-to-fmri-analysis
#4
Jonathan D Cohen, Nathaniel Daw, Barbara Engelhardt, Uri Hasson, Kai Li, Yael Niv, Kenneth A Norman, Jonathan Pillow, Peter J Ramadge, Nicholas B Turk-Browne, Theodore L Willke
Analysis methods in cognitive neuroscience have not always matched the richness of fMRI data. Early methods focused on estimating neural activity within individual voxels or regions, averaged over trials or blocks and modeled separately in each participant. This approach mostly neglected the distributed nature of neural representations over voxels, the continuous dynamics of neural activity during tasks, the statistical benefits of performing joint inference over multiple participants and the value of using predictive models to constrain analysis...
February 23, 2017: Nature Neuroscience
https://www.readbyqxmd.com/read/28100748/independent-neural-computation-of-value-from-other-people-s-confidence
#5
Daniel Campbell-Meiklejohn, Arndis Simonsen, Chris D Frith, Nathaniel D Daw
Expectation of reward can be shaped by the observation of actions and expressions of other people in one's environment. A person's apparent confidence in the likely reward of an action, for instance, makes qualities of their evidence, not observed directly, socially accessible. This strategy is computationally distinguished from associative learning methods that rely on direct observation, by its use of inference from indirect evidence. In twenty-three healthy human subjects, we isolated effects of first-hand experience, other people's choices, and the mediating effect of their confidence, on decision-making and neural correlates of value within ventromedial prefrontal cortex (vmPFC)...
January 18, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28046006/suboptimal-criterion-learning-in-static-and-dynamic-environments
#6
Elyse H Norton, Stephen M Fleming, Nathaniel D Daw, Michael S Landy
Humans often make decisions based on uncertain sensory information. Signal detection theory (SDT) describes detection and discrimination decisions as a comparison of stimulus "strength" to a fixed decision criterion. However, recent research suggests that current responses depend on the recent history of stimuli and previous responses, suggesting that the decision criterion is updated trial-by-trial. The mechanisms underpinning criterion setting remain unknown. Here, we examine how observers learn to set a decision criterion in an orientation-discrimination task under both static and dynamic conditions...
January 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28004960/self-evaluation-of-decision-making-a-general-bayesian-framework-for-metacognitive-computation
#7
Stephen M Fleming, Nathaniel D Daw
People are often aware of their mistakes, and report levels of confidence in their choices that correlate with objective performance. These metacognitive assessments of decision quality are important for the guidance of behavior, particularly when external feedback is absent or sporadic. However, a computational framework that accounts for both confidence and error detection is lacking. In addition, accounts of dissociations between performance and metacognition have often relied on ad hoc assumptions, precluding a unified account of intact and impaired self-evaluation...
January 2017: Psychological Review
https://www.readbyqxmd.com/read/27940996/independent-neural-computation-of-value-from-other-people-s-confidence
#8
Daniel Campbell-Meiklejohn, Arndis Simonsen, Chris D Frith, Nathaniel D Daw
Expectation of reward can be shaped by the observation of actions and expressions of other people in one's environment. A person's apparent confidence in the likely reward of an action, for instance, makes qualities of their evidence, not observed directly, socially accessible. This strategy is computationally distinguished from associative learning methods that rely on direct observation, by its use of inference from indirect evidence. In twenty-three healthy human subjects, we isolated effects of first-hand experience, other people's choices, and the mediating effect of their confidence, on decision-making and neural correlates of value within ventromedial prefrontal cortex (vmPFC)...
December 9, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27618944/reinforcement-learning-and-episodic-memory-in-humans-and-animals-an-integrative-framework
#9
REVIEW
Samuel J Gershman, Nathaniel D Daw
We review the psychology and neuroscience of reinforcement learning (RL), which has experienced significant progress in the past two decades, enabled by the comprehensive experimental study of simple learning and decision-making tasks. However, one challenge in the study of RL is computational: The simplicity of these tasks ignores important aspects of reinforcement learning in the real world: (a) State spaces are high-dimensional, continuous, and partially observable; this implies that (b) data are relatively sparse and, indeed, precisely the same situation may never be encountered twice; furthermore, (c) rewards depend on the long-term consequences of actions in ways that violate the classical assumptions that make RL tractable...
January 3, 2017: Annual Review of Psychology
https://www.readbyqxmd.com/read/27387647/taking-psychiatry-research-online
#10
Claire M Gillan, Nathaniel D Daw
Psychiatry is in need of a major overhaul. In order to improve the precision with which we can treat, classify, and research mental health problems, we need bigger datasets than ever before. Web-based data collection provides a novel solution.
July 6, 2016: Neuron
https://www.readbyqxmd.com/read/27175984/reduced-model-based-decision-making-in-schizophrenia
#11
Adam J Culbreth, Andrew Westbrook, Nathaniel D Daw, Matthew Botvinick, Deanna M Barch
Individuals with schizophrenia have a diminished ability to use reward history to adaptively guide behavior. However, tasks traditionally used to assess such deficits often rely on multiple cognitive and neural processes, leaving etiology unresolved. In the current study, we adopted recent computational formalisms of reinforcement learning to distinguish between model-based and model-free decision-making in hopes of specifying mechanisms associated with reinforcement-learning dysfunction in schizophrenia. Under this framework, decision-making is model-free to the extent that it relies solely on prior reward history, and model-based if it relies on prospective information such as motivational state, future consequences, and the likelihood of obtaining various outcomes...
2016: Journal of Abnormal Psychology
https://www.readbyqxmd.com/read/27171199/instructed-knowledge-shapes-feedback-driven-aversive-learning-in-striatum-and-orbitofrontal-cortex-but-not-the-amygdala
#12
Lauren Y Atlas, Bradley B Doll, Jian Li, Nathaniel D Daw, Elizabeth A Phelps
Socially-conveyed rules and instructions strongly shape expectations and emotions. Yet most neuroscientific studies of learning consider reinforcement history alone, irrespective of knowledge acquired through other means. We examined fear conditioning and reversal in humans to test whether instructed knowledge modulates the neural mechanisms of feedback-driven learning. One group was informed about contingencies and reversals. A second group learned only from reinforcement. We combined quantitative models with functional magnetic resonance imaging and found that instructions induced dissociations in the neural systems of aversive learning...
2016: ELife
https://www.readbyqxmd.com/read/27110917/reward-and-choice-encoding-in-terminals-of-midbrain-dopamine-neurons-depends-on-striatal-target
#13
Nathan F Parker, Courtney M Cameron, Joshua P Taliaferro, Junuk Lee, Jung Yoon Choi, Thomas J Davidson, Nathaniel D Daw, Ilana B Witten
Dopaminergic (DA) neurons in the midbrain provide rich topographic innervation of the striatum and are central to learning and to generating actions. Despite the importance of this DA innervation, it remains unclear whether and how DA neurons are specialized on the basis of the location of their striatal target. Thus, we sought to compare the function of subpopulations of DA neurons that target distinct striatal subregions in the context of an instrumental reversal learning task. We identified key differences in the encoding of reward and choice in dopamine terminals in dorsal versus ventral striatum: DA terminals in ventral striatum responded more strongly to reward consumption and reward-predicting cues, whereas DA terminals in dorsomedial striatum responded more strongly to contralateral choices...
June 2016: Nature Neuroscience
https://www.readbyqxmd.com/read/27105903/motivational-context-modulates-prediction-error-response-in-schizophrenia
#14
Jenna M Reinen, Jared X Van Snellenberg, Guillermo Horga, Anissa Abi-Dargham, Nathaniel D Daw, Daphna Shohamy
BACKGROUND: Recent findings demonstrate that patients with schizophrenia are worse at learning to predict rewards than losses, suggesting that motivational context modulates learning in this disease. However, these findings derive from studies in patients treated with antipsychotic medications, D2 receptor antagonists that may interfere with the neural systems that underlie motivation and learning. Thus, it remains unknown how motivational context affects learning in schizophrenia, separate from the effects of medication...
November 2016: Schizophrenia Bulletin
https://www.readbyqxmd.com/read/27099987/the-expanding-role-of-dopamine
#15
COMMENT
Bradley B Doll, Nathaniel D Daw
Evidence increasingly suggests that dopaminergic neurons play a more sophisticated role in predicting rewards than previously thought.
April 21, 2016: ELife
https://www.readbyqxmd.com/read/27084852/from-creatures-of-habit-to-goal-directed-learners-tracking-the-developmental-emergence-of-model-based-reinforcement-learning
#16
Johannes H Decker, A Ross Otto, Nathaniel D Daw, Catherine A Hartley
Theoretical models distinguish two decision-making strategies that have been formalized in reinforcement-learning theory. A model-based strategy leverages a cognitive model of potential actions and their consequences to make goal-directed choices, whereas a model-free strategy evaluates actions based solely on their reward history. Research in adults has begun to elucidate the psychological mechanisms and neural substrates underlying these learning processes and factors that influence their relative recruitment...
June 2016: Psychological Science
https://www.readbyqxmd.com/read/26928075/characterizing-a-psychiatric-symptom-dimension-related-to-deficits-in-goal-directed-control
#17
Claire M Gillan, Michal Kosinski, Robert Whelan, Elizabeth A Phelps, Nathaniel D Daw
Prominent theories suggest that compulsive behaviors, characteristic of obsessive-compulsive disorder and addiction, are driven by shared deficits in goal-directed control, which confers vulnerability for developing rigid habits. However, recent studies have shown that deficient goal-directed control accompanies several disorders, including those without an obvious compulsive element. Reasoning that this lack of clinical specificity might reflect broader issues with psychiatric diagnostic categories, we investigated whether a dimensional approach would better delineate the clinical manifestations of goal-directed deficits...
March 1, 2016: ELife
https://www.readbyqxmd.com/read/26818509/variability-in-dopamine-genes-dissociates-model-based-and-model-free-reinforcement-learning
#18
Bradley B Doll, Kevin G Bath, Nathaniel D Daw, Michael J Frank
UNLABELLED: Considerable evidence suggests that multiple learning systems can drive behavior. Choice can proceed reflexively from previous actions and their associated outcomes, as captured by "model-free" learning algorithms, or flexibly from prospective consideration of outcomes that might occur, as captured by "model-based" learning algorithms. However, differential contributions of dopamine to these systems are poorly understood. Dopamine is widely thought to support model-free learning by modulating plasticity in striatum...
January 27, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/26752158/coherent-neuronal-ensembles-are-rapidly-recruited-when-making-a-look-reach-decision
#19
Yan T Wong, Margaret M Fabiszak, Yevgeny Novikov, Nathaniel D Daw, Bijan Pesaran
Selecting and planning actions recruits neurons across many areas of the brain, but how ensembles of neurons work together to make decisions is unknown. Temporally coherent neural activity may provide a mechanism by which neurons coordinate their activity to make decisions. If so, neurons that are part of coherent ensembles may predict movement choices before other ensembles of neurons. We recorded neuronal activity in the lateral and medial banks of the intraparietal sulcus (IPS) of the posterior parietal cortex while monkeys made choices about where to look and reach...
February 2016: Nature Neuroscience
https://www.readbyqxmd.com/read/26685155/dopamine-selectively-remediates-model-based-reward-learning-a-computational-approach
#20
Madeleine E Sharp, Karin Foerde, Nathaniel D Daw, Daphna Shohamy
Patients with loss of dopamine due to Parkinson's disease are impaired at learning from reward. However, it remains unknown precisely which aspect of learning is impaired. In particular, learning from reward, or reinforcement learning, can be driven by two distinct computational processes. One involves habitual stamping-in of stimulus-response associations, hypothesized to arise computationally from 'model-free' learning. The other, 'model-based' learning, involves learning a model of the world that is believed to support goal-directed behaviour...
February 2016: Brain: a Journal of Neurology
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