The mesostriatal dopamine system is prominently implicated in model-free reinforcement learning, with fMRI BOLD signals in ventral striatum notably covarying with model-free prediction errors. However, latent learning and devaluation studies show that behavior also shows hallmarks of model-based planning, and the interaction between model-based and model-free values, prediction errors, and preferences is underexplored. We designed a multistep decision task in which model-based and model-free influences on human choice behavior could be distinguished. By showing that choices reflected both influences we could (...) then test the purity of the ventral striatal BOLD signal as a model-free report. Contrary to expectations, the signal reflected both model-free and model-based predictions in proportions matching those that best explained choice behavior. These results challenge the notion of a separate model-free learner and suggest a more integrated computational architecture for high-level human decision-making. (shrink)
Although seemingly irrational choice abounds, the rules governing these mis‐steps that might provide hints about the factors limiting normative behavior are unclear. We consider three experimental tasks, which probe different aspects of non‐normative choice under uncertainty. We argue for systematic statistical, algorithmic, and implementational sources of irrationality, including incomplete evaluation of long‐run future utilities, Pavlovian actions, and habits, together with computational and statistical noise and uncertainty. We suggest structural and functional adaptations that minimize their maladaptive effects.
Mallarmé's reputation as a seminal thinker has steadily grown, yet his literary theory has received little attention and the great theoretical articles of his later years have never been properly studied. This book represents the first attempt to examine the later Mallarmé's extraordinary and systematic literary idealism through a careful scrutiny of his work. Dayan makes selective use of the textual approaches of certain post-structuralist theorists, especially Derrida, pointing out the many similarities between their positions and Mallarmé's, but also noting (...) the vital differences. These differences, Dayan argues help to explain not only Mallarmé's continuing elusiveness, but also the failure of modern literary theory to face the question that Mallarmé always considered central: What is good poetry? (shrink)
Modern literature has always been obsessed by music. It cannot seem to think about itself without obsessing about music. And music has returned the favour. The Routledge Companion to Music and Modern Literature addresses this relationship as a significant contribution to the burgeoning field of word and music studies. The 37 chapters within consider the partnership through four lenses-the universal, opera and literature, musical and literary forms, and popular music and literature-and touch upon diverse and pertinent themes for our modern (...) times, ranging from misogyny to queerness, racial inequality to the claimed universality of whiteness. This Companion therefore offers an essential resource for all who try to decode the musico-literary exchange. (shrink)
One character in Cortázar's novel truly believes in cosmic rhythm. This belief is characteristic of a magical view of the universe central to 1960s counterculture. The other characters in Los Premios, like the implied narrator, reject Persio's essentialism; they dismiss the notion that there is really any rhythm common to art, humanity, and the universe. However, there are key points in the narrative, inspired by falling in love and by works of art, at which their world does appear patterned by (...) just such a rhythm, a ‘swing cósmico’. The novel itself turns out to depend on the intermittent conviction of this rhythm, not objectively embedded in anything, but always seen, living, and dying in time; the price of art is the acceptance of this rhythmed mortality. (shrink)
Bayesian decision theory provides a simple formal elucidation of some of the ways that representation and representational abstraction are involved with, and exploit, both prediction and its rather distant cousin, predictive coding. Both model-free and model-based methods are involved.
A cartoon description of the goals of cognitive science and neuroscience might read respectively “How the mind works” and “How the brain works.” In this caricature, there would seem to be little overlap in the vocabularies employed by each domain. The cartoon cognitive scientist could speak at length about decision making and short‐term memory in a relatively self‐consistent manner, without any need to make reference to the language of neuroscience. Likewise, the cartoon neuroscientist could provide an immense body of physical (...) detail about the function of neurons, synapses, and their component parts. She could even build models about how collections of neurons work together, or even how they might have developed. (shrink)
We use neural reinforcement learning concepts including Pavlovian versus instrumental control, liking versus wanting, model-based versus model-free control, online versus offline learning and planning, and internal versus external actions and control to reflect on putative conflicts between short-term temptations and long-term goals.
Previous research has shown that short-term fasting in healthy individuals is associated with changes in risky decision-making. The current experiment was designed to examine the influence of short-term fasting in healthy individuals on four types of impulsivity: reflection impulsivity, risky decision-making, delay aversion, and action inhibition. Participants were tested twice, once when fasted for 20 hours, and once when satiated. Participants demonstrated impaired action inhibition when fasted; committing significantly more errors of commission during a food-related Affective Shifting Task. Participants also (...) displayed decreased reflection impulsivity when fasted, opening significantly more boxes during the Information Sampling Task (IST). There were no significant differences in performance between fasted and satiated sessions for risky decision-making or delay aversion. These findings may have implications for understanding eating disorders such as Bulimia Nervosa (BN). Although BN has been characterised as a disorder of poor impulse control, inconsistent findings when comparing individuals with BN and healthy individuals on behavioural measures of impulsivity question this characterisation. Since individuals with BN undergo periods of short-term fasting, the inconsistent findings could be due to differences in the levels of satiation of participants. The current results indicate that fasting can affect performance on the IST, a measure of impulsivity previously studied in BN, whilst performance on other impulsivity measures were unaffected. However, the results from the IST were contrary to the original hypothesis and should be replicated before specific conclusions can be made. (shrink)