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Nathaniel Daw

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https://www.readbyqxmd.com/read/29750987/the-opportunity-cost-of-time-modulates-cognitive-effort
#1
A Ross Otto, Nathaniel D Daw
A spate of recent work demonstrates that humans seek to avoid the expenditure of cognitive effort, much like physical effort or economic resources. Less is clear, however, about the circumstances dictating how and when people decide to expend cognitive effort. Here we adopt a popular theory of opportunity costs and response vigor and to elucidate this question. This account, grounded in Reinforcement Learning, formalizes a trade-off between two costs: the harder work assumed necessary to emit faster actions and the opportunity cost inherent in acting more slowly (i...
May 8, 2018: Neuropsychologia
https://www.readbyqxmd.com/read/29681530/more-than-the-sum-of-its-parts-a-role-for-the-hippocampus-in-configural-reinforcement-learning
#2
Katherine Duncan, Bradley B Doll, Nathaniel D Daw, Daphna Shohamy
People often perceive configurations rather than the elements they comprise, a bias that may emerge because configurations often predict outcomes. But how does the brain learn to associate configurations with outcomes and how does this learning differ from learning about individual elements? We combined behavior, reinforcement learning models, and functional imaging to understand how people learn to associate configurations of cues with outcomes. We found that configural learning depended on the relative predictive strength of elements versus configurations and was related to both the strength of BOLD activity and patterns of BOLD activity in the hippocampus...
April 18, 2018: Neuron
https://www.readbyqxmd.com/read/29593300/surviving-threats-neural-circuit-and-computational-implications-of-a-new-taxonomy-of-defensive-behaviour
#3
REVIEW
Joseph LeDoux, Nathaniel D Daw
Research on defensive behaviour in mammals has in recent years focused on elicited reactions; however, organisms also make active choices when responding to danger. We propose a hierarchical taxonomy of defensive behaviour on the basis of known psychological processes. Included are three categories of reactions (reflexes, fixed reactions and habits) and three categories of goal-directed actions (direct action-outcome behaviours and actions based on implicit or explicit forecasting of outcomes). We then use this taxonomy to guide a summary of findings regarding the underlying neural circuits...
May 2018: Nature Reviews. Neuroscience
https://www.readbyqxmd.com/read/29531361/neural-mediators-of-changes-of-mind-about-perceptual-decisions
#4
Stephen M Fleming, Elisabeth J van der Putten, Nathaniel D Daw
Changing one's mind on the basis of new evidence is a hallmark of cognitive flexibility. To revise our confidence in a previous decision, we should use new evidence to update beliefs about choice accuracy. How this process unfolds in the human brain, however, remains unknown. Here we manipulated whether additional sensory evidence supports or negates a previous motion direction discrimination judgment while recording markers of neural activity in the human brain using fMRI. A signature of post-decision evidence (change in log-odds correct) was selectively observed in the activity of posterior medial frontal cortex...
April 2018: Nature Neuroscience
https://www.readbyqxmd.com/read/29507207/how-cognitive-and-reactive-fear-circuits-optimize-escape-decisions-in-humans
#5
Song Qi, Demis Hassabis, Jiayin Sun, Fangjian Guo, Nathaniel Daw, Dean Mobbs
Flight initiation distance (FID), the distance at which an organism flees from an approaching threat, is an ecological metric of cost-benefit functions of escape decisions. We adapted the FID paradigm to investigate how fast- or slow-attacking "virtual predators" constrain escape decisions. We show that rapid escape decisions rely on "reactive fear" circuits in the periaqueductal gray and midcingulate cortex (MCC), while protracted escape decisions, defined by larger buffer zones, were associated with "cognitive fear" circuits, which include posterior cingulate cortex, hippocampus, and the ventromedial prefrontal cortex, circuits implicated in more complex information processing, cognitive avoidance strategies, and behavioral flexibility...
March 20, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29398218/a-perceptual-inference-mechanism-for-hallucinations-linked-to-striatal-dopamine
#6
Clifford M Cassidy, Peter D Balsam, Jodi J Weinstein, Rachel J Rosengard, Mark Slifstein, Nathaniel D Daw, Anissa Abi-Dargham, Guillermo Horga
Hallucinations, a cardinal feature of psychotic disorders such as schizophrenia, are known to depend on excessive striatal dopamine. However, an underlying cognitive mechanism linking dopamine dysregulation and the experience of hallucinatory percepts remains elusive. Bayesian models explain perception as an optimal combination of prior expectations and new sensory evidence, where perceptual distortions such as illusions and hallucinations may occur if prior expectations are afforded excessive weight. Such excessive weight of prior expectations, in turn, could stem from a gain-control process controlled by neuromodulators such as dopamine...
February 19, 2018: Current Biology: CB
https://www.readbyqxmd.com/read/28945743/predictive-representations-can-link-model-based-reinforcement-learning-to-model-free-mechanisms
#7
Evan M Russek, Ida Momennejad, Matthew M Botvinick, Samuel J Gershman, Nathaniel D Daw
Humans and animals are capable of evaluating actions by considering their long-run future rewards through a process described using model-based reinforcement learning (RL) algorithms. The mechanisms by which neural circuits perform the computations prescribed by model-based RL remain largely unknown; however, multiple lines of evidence suggest that neural circuits supporting model-based behavior are structurally homologous to and overlapping with those thought to carry out model-free temporal difference (TD) learning...
September 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28900892/increased-locus-coeruleus-tonic-activity-causes-disengagement-from-a-patch-foraging-task
#8
Gary A Kane, Elena M Vazey, Robert C Wilson, Amitai Shenhav, Nathaniel D Daw, Gary Aston-Jones, Jonathan D Cohen
High levels of locus coeruleus (LC) tonic activity are associated with distraction and poor performance within a task. Adaptive gain theory (AGT; Aston-Jones & Cohen, 2005) suggests that this may reflect an adaptive function of the LC, encouraging search for more remunerative opportunities in times of low utility. Here, we examine whether stimulating LC tonic activity using designer receptors (DREADDs) promotes searching for better opportunities in a patch-foraging task as the value of a patch diminishes...
December 2017: Cognitive, Affective & Behavioral Neuroscience
https://www.readbyqxmd.com/read/28653668/reminders-of-past-choices-bias-decisions-for-reward-in-humans
#9
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
#10
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
#11
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
#12
REVIEW
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
REVIEW
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
#19
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...
August 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
#20
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...
May 12, 2016: ELife
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