Aspirations, adaptive learning and cooperation in repeated games

Game Theory;Repeated Games

Flies Sleep on It, or Fuhgeddaboudit!

Many studies in diverse organisms, including humans, have demonstrated a fundamental role for sleep in the formation of memories. A new study by Berry et al. indicates that, in fruit flies, sleep accomplishes this in part by preventing an active process of forgetting

Words without Near-Repetitions

We find an infinite word w on four symbols with the following property: Two occurrences of any block in w must be separated by more than the length of the block. That is, in any subword of w of the form xyx, the length of y is greater than the length of x. This answers a question of C. Edmunds connected to the Burnside problem for groups.The research of the first author was supported by an NSERC Operating Grant. The second author was supported by an NSERC Undergraduate Summer Research Award.https://www.cambridge.org/core/journals/canadian-mathematical-bulletin/article/words-without-nearrepetitions/F86509D865F222F1FC63ACA8545C069

The human 'pitch center' responds differently to iterated noise and Huggins pitch

A magnetoencephalographic marker for pitch analysis (the pitch onset response) has been reported for different types of pitch-evoking stimuli, irrespective of whether the acoustic cues for pitch are monaurally or binaurally produced. It is claimed that the pitch onset response reflects a common cortical representation for pitch, putatively in lateral Heschl's gyrus. The result of this functional MRI study sheds doubt on this assertion. We report a direct comparison between iterated ripple noise and Huggins pitch in which we reveal a different pattern of auditory cortical activation associated with each pitch stimulus, even when individual variability in structure-function relations is accounted for. Our results suggest it may be premature to assume that lateral Heschl's gyrus is a universal pitch center

Asymmetric Power Among Agents and the Generation and Maintenance of Cooperation in International Relations

The question addressed in this analysis is whether endowing agents with various forms of asymmetric power makes cooperation more likely across a variety of structural settings of conflict and cooperation present in international relations. To address this question, an agent-based model incorporating asymmetric power among agents in a set of (2 Â 2) games that represent different forms of conflict and cooperation prevalent in international relations (Chicken, Stag, Assurance, Deadlock, and Prisoner's Dilemma) is developed and analyzed via simulation. Simulation results indicate that the introduction of asymmetric power substantially increases the chances that both cooperative agents survive and cooperative worlds evolve. This is particularly the case when agents are endowed with the ability to selectively interact with other agents. Also, anticipated variations in outcomes across the game structures regarding the likelihood of cooperation are supported. Whether and how cooperation evolves in social settings characterized by the presence of selfish agents engaged in repeated relations without central authority has been of considerable importance to scholars of international politics and of interest to scholars across all the social sciences as well as philosophy, biology, and computer science. 1 International relations scholars have been particularly interested in various features of nation-states, the relations among nation-states, and the structural environment in which nation-states are embedded that make cooperation either possible or more likely. Studying the evolution of cooperation in the context of the Repeated Prisoner's Dilemma (RPD) has proven to be quite fruitful for international relations scholars. Yet, the RPD framework is also restrictive in a variety of ways. 3 For instance, while the RPD captures one important type of relationship among nation-states in the international system, there are a number of other structural settings that (1984), the Repeated Prisoner's Dilemma (RPD) has become the central metaphor for the evolution of cooperation in populations of selfish agents without central authority

A gauge invariant chiral unitary framework for kaon photo- and electroproduction on the proton

We present a gauge invariant approach to photoproduction of mesons on nucleons within a chiral unitary framework. The interaction kernel for meson-baryon scattering is derived from the chiral effective Lagrangian and iterated in a Bethe-Salpeter equation. Within the leading order approximation to the interaction kernel, data on kaon photoproduction from SAPHIR, CLAS and CBELSA/TAPS are analyzed in the threshold region. The importance of gauge invariance and the precision of various approximations in the interaction kernel utilized in earlier works are discussed.Comment: 23 pages, 13 figs, EPJ A styl

Interpreting wde-band neural activity using convolutional neural networks

Rapid progress in technologies such as calcium imaging and electrophysiology has seen a dramatic increase in the size and extent of neural recordings. Even so, interpretation of this data requires considerable knowledge about the nature of the representation and often depends on manual operations. Decoding provides a means to infer the information content of such recordings but typically requires highly processed data and prior knowledge of the encoding scheme. Here, we developed a deep-learning framework able to decode sensory and behavioral variables directly from wide-band neural data. The network requires little user input and generalizes across stimuli, behaviors, brain regions, and recording techniques. Once trained, it can be analyzed to determine elements of the neural code that are informative about a given variable. We validated this approach using electrophysiological and calcium-imaging data from rodent auditory cortex and hippocampus as well as human electrocorticography (ECoG) data. We show successful decoding of finger movement, auditory stimuli, and spatial behaviors – including a novel representation of head direction - from raw neural activity