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Credit Assignment

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lightbulbAbout this topic
Credit assignment refers to the process of determining the contribution of individual components or agents in a system to the overall outcome or performance. It is a critical concept in fields such as machine learning, psychology, and economics, where understanding the influence of specific actions or decisions on results is essential for learning and optimization.
lightbulbAbout this topic
Credit assignment refers to the process of determining the contribution of individual components or agents in a system to the overall outcome or performance. It is a critical concept in fields such as machine learning, psychology, and economics, where understanding the influence of specific actions or decisions on results is essential for learning and optimization.

Key research themes

1. How can credit assignment be optimized in multi-agent systems and neural networks for effective resource allocation and learning?

This research theme explores algorithmic and computational frameworks for credit assignment tailored to multi-agent settings and neural networks, focusing on how credit (or reward) attribution to individual agents or neurons can be optimized to enhance system efficiency and learning performance. It addresses challenges such as distributing global rewards among multiple agents, biologically plausible credit assignment in deep networks, and credit assignment under constraints like task start thresholds and multi-score rewards, relevant to complex environments such as smart cities and artificial intelligence systems.

Key finding: This paper proposes a novel solution to resource allocation in smart cities by formulating the problem as a multi-agent credit assignment (MCA) issue mapped to a bankruptcy game, introducing a task start threshold (TST)... Read more
Key finding: The authors introduce a self-adaptive mechanism leveraging a dynamic extension of the multi-armed bandit framework to guide the allocation of computational resources among different species in a cooperative coevolutionary... Read more
Key finding: The study decomposes traditional Backpropagation into interacting local learning agents and identifies that error signals in deep networks factorize into a global scalar error and a complex, biologically implausible... Read more

2. What mathematical and computational frameworks can improve credit scoring and optimal credit allocation in financial systems?

This theme investigates advanced modeling approaches and mathematical frameworks to enhance credit risk assessment and credit allocation decisions in financial contexts. It examines how to move beyond traditional dichotomous credit scoring classification into optimal credit allocation methodologies maximizing financial returns, integrating machine learning techniques for credit scoring with explainability, and minimizing total costs in credit decisions through staged evaluation models. The insights contribute to bridging the gap between predictive accuracy and practical credit allocation, regulatory requirements, and explainability in risk management.

Key finding: This paper introduces a novel conceptual framework connecting probability of default (PD) to optimal credit allocation through the Kelly criterion, shifting focus from binary default classification to maximizing risk-adjusted... Read more
Key finding: This work presents a unified mathematical framework combining various machine learning algorithms (logistic regression, decision trees, SVM, neural networks) with advanced optimization techniques (Particle Swarm Optimization,... Read more
Key finding: The paper develops a two-stage credit scoring model minimizing the total cost associated with granting credit, including costs of defaults, denials of good applicants, and information acquisition. The first stage classifies... Read more

3. How do neural mechanisms and learning models address the credit assignment problem in biological and artificial learning systems?

This theme focuses on the neurobiological and computational foundations of credit assignment in the brain and artificial networks, probing how neurons encode and link outcomes to preceding causal factors in learning. It includes studies of prefrontal cortex representations that support credit assignment over time, the modulation of synaptic plasticity by neuromodulators and glial cells in spike-timing dependent plasticity (STDP), and cerebellar learning models that implement stochastic gradient descent via complex spikes as perturbations. These insights elucidate mechanisms underlying associative learning, reinforcement, and maladaptive behaviors, and inform biologically inspired algorithms for credit assignment.

Key finding: Using electrophysiological recordings from the dorsolateral prefrontal cortex (dlPFC) of rhesus macaques engaged in a task requiring credit assignment, this study found that dlPFC neurons maintain stable representations of... Read more
Key finding: This review consolidates evidence that spike-timing dependent plasticity (STDP), traditionally viewed as a two-factor Hebbian mechanism dependent on pre- and postsynaptic activity timing, is modulated by a third factor... Read more
Key finding: The paper proposes a novel cerebellar learning algorithm termed stochastic gradient descent with estimated global errors (SGDEGE), wherein spontaneous complex spikes perturb ongoing movements, create eligibility traces, and... Read more
by Yuki Sakai and 
1 more
Key finding: This study models obsessive-compulsive disorder (OCD) symptoms as maladaptive implicit behaviors arising from an imbalance in memory trace decay timescales for positive and negative prediction errors within reinforcement... Read more

All papers in Credit Assignment

The cerebellum aids the learning of fast, coordinated movements. According to current consensus, erroneously active parallel fibre synapses are depressed by complex spikes signalling movement errors. However, this theory cannot solve the... more
Asimetrik bilgiye dayanan piyasa teorileri literatürde uzun bir zamandır incelenmektedir. Tam olmayan bilgiye dayalı modeller araştırmacıların yoğunlaştığı alanlardır. Bir çok piyasa gibi kredi piyasalarında da asimetrik bilgi sorununa... more
Small variations in how a task is designed can lead humans to trade off one set of strategies for another. In this paper we discuss our failure to model such tradeoffs in the Blocks World task using ACT-RÕs default mechanism for selecting... more
Finansal sektor, genel anlamda fon arz ve talebinin eslestirilmesi amaciyla kurulmustur. Fon arz edenler, likiditeden vazgecmeleri karsiliginda bankalardan faiz talep etmekte, fon ihtiyacinda olanlar ise, belirli bir faiz orani... more
This paper proposes a self-adaptation mechanism to manage the resources allocated to the different species comprising a cooperative coevolutionary algorithm. The proposed approach relies on a dynamic extension to the well-known... more
In spike-timing dependent plasticity (STDP) change in synaptic strength depends on the timing of pre- vs. postsynaptic spiking activity. Since STDP is in compliance with Hebb's postulate, it is considered one of the major mechanisms... more
La pubblicazione di questo volume è stata subordinata alla valutazione positiva espressa da due docenti esterni anonimi, sorteggiati dalla Direzione scientifica all'interno del Comitato editoriale permanente, secondo il modello della... more
by Yuki Sakai and 
1 more
We may view most of our daily activities as rational action selections; however, we sometimes reinforce maladaptive behaviors despite having explicit environmental knowledge. In this study, we model obsessive-compulsive disorder (OCD)... more
There are various important choices that need to be assumed when building and training a neural network. One has to determine which loss function to be used, how many layers to be include, what stride and kernel size to use for each... more
This work shows that a differentiable activation function is not necessary any more for error backpropagation. The derivative of the activation function can be replaced by an iterative temporal differencing using fixed random feedback... more
Abstract���This paper presents i-AA1���, a constructive, incremental learning algorithm for a special class of weightless, self-organizing networks. In i-AA1���, learning consists of adapting the nodes' functions and the... more
Reinforcement learning (RL) has recently regained popularity, with major achievements such as beating the European game of Go champion. Here, for the first time, we show that RL can be used efficiently to train a spiking neural network... more
Öz Bankacılık sektörünün kredilendirme faaliyetlerinde asimetrik bilgi sorununun önemli bir rol oynadığı görülmektedir. Kredi piyasalarında asimetrik bilgi problemi sonucunda ters seçim ve ahlaki tehlike olmak üzere iki önemli sorun... more
Deep learning is currently the subject of intensive study. However, fundamental concepts such as representations are not formally defined – researchers " know them when they see them " – and there is no common language for describing and... more
We present a novel method to train predictive Gaussian distributions p(z|x) for regression problems with neural networks. While most approaches either ignore or explicitly model the variance as another response variable, it is trained... more
Deep learning is currently the subject of intensive study. However, fundamental concepts such as representations are not formally defined -- researchers "know them when they see them" -- and there is no common language for describing and... more
Methods from convex optimization such as accelerated gradient descent are widely used as building blocks for deep learning algorithms. However, the reasons for their empirical success are unclear, since neural networks are not convex and... more
This paper suggests a learning-theoretic perspective on how synaptic plasticity benefits global brain functioning. We introduce a model, the selectron, that (i) arises as the fast time constant limit of leaky integrate-and-fire neurons... more
Error backpropagation is an extremely effective algorithm for assigning credit in artificial neural networks. However, weight updates under Backprop depend on lengthy recursive computations and require separate output and error messages... more
We investigate cortical learning from the perspective of mechanism design. First, we show that discretizing standard models of neurons and synaptic plasticity leads to rational agents maximizing simple scoring rules. Second, our main... more
In behavior coordination, several primitive behav- iors are “combined” t o generate a resultant action t o drive the robot. T h e weights across the primitive be- haviors should be properly determined according t o the situations that the... more
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