Goal-Directed Reinforcement Learning Using Variable Learning Rate

1998 ◽  
pp. 131-140 ◽  
Author(s):  
Arthur P. de S. Braga ◽  
Aluizio F. R. Araújo
Keyword(s):  
Reinforcement Learning ◽  
Learning Rate

scholarly journals Reinforcement Learning for Routing in Cognitive Radio Ad Hoc Networks

2014 ◽  
Vol 2014 ◽  
pp. 1-22 ◽  
Author(s):  
Hasan A. A. Al-Rawi ◽  
Kok-Lim Alvin Yau ◽  
Hafizal Mohamad ◽  
Nordin Ramli ◽  
Wahidah Hashim
Keyword(s):  
Reinforcement Learning ◽  
Cognitive Radio ◽  
Network Performance ◽  
Ad Hoc ◽  
Research Area ◽  
Learning Rate ◽  
Destination Node ◽  
Reward Function ◽  
New Approaches ◽  
Exploitation And Exploration

Cognitive radio (CR) enables unlicensed users (or secondary users, SUs) to sense for and exploit underutilized licensed spectrum owned by the licensed users (or primary users, PUs). Reinforcement learning (RL) is an artificial intelligence approach that enables a node to observe, learn, and make appropriate decisions on action selection in order to maximize network performance. Routing enables a source node to search for a least-cost route to its destination node. While there have been increasing efforts to enhance the traditional RL approach for routing in wireless networks, this research area remains largely unexplored in the domain of routing in CR networks. This paper applies RL in routing and investigates the effects of various features of RL (i.e., reward function, exploitation, and exploration, as well as learning rate) through simulation. New approaches and recommendations are proposed to enhance the features in order to improve the network performance brought about by RL to routing. Simulation results show that the RL parameters of the reward function, exploitation, and exploration, as well as learning rate, must be well regulated, and the new approaches proposed in this paper improves SUs’ network performance without significantly jeopardizing PUs’ network performance, specifically SUs’ interference to PUs.

scholarly journals Effect of lysergic acid diethylamide (LSD) on reinforcement learning in humans

2020 ◽  
Author(s):  
Jonathan W. Kanen ◽  
Qiang Luo ◽  
Mojtaba R. Kandroodi ◽  
Rudolf N. Cardinal ◽  
Trevor W. Robbins ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Computational Modelling ◽  
Lysergic Acid ◽  
Learning Rate ◽  
Lysergic Acid Diethylamide ◽  
Immediate Feedback ◽  
Healthy Humans ◽  
Learning Rates ◽  
Psychedelic Drugs ◽  
The Impact

AbstractThe non-selective serotonin 2A (5-HT2A) receptor agonist lysergic acid diethylamide (LSD) holds promise as a treatment for some psychiatric disorders. Psychedelic drugs such as LSD have been suggested to have therapeutic actions through their effects on learning. The behavioural effects of LSD in humans, however, remain largely unexplored. Here we examined how LSD affects probabilistic reversal learning in healthy humans. Conventional measures assessing sensitivity to immediate feedback (“win-stay” and “lose-shift” probabilities) were unaffected, whereas LSD increased the impact of the strength of initial learning on perseveration. Computational modelling revealed that the most pronounced effect of LSD was enhancement of the reward learning rate. The punishment learning rate was also elevated. Increased reinforcement learning rates suggest LSD induced a state of heightened plasticity. These results indicate a potential mechanism through which revision of maladaptive associations could occur.

scholarly journals Modeling changes in probabilistic reinforcement learning during adolescence

2021 ◽  
Vol 17 (7) ◽  
pp. e1008524
Author(s):  
Liyu Xia ◽  
Sarah L. Master ◽  
Maria K. Eckstein ◽  
Beth Baribault ◽  
Ronald E. Dahl ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Learning Task ◽  
Learning Rate ◽  
Integration Time ◽  
Daily Experience ◽  
Salivary Testosterone ◽  
Probabilistic Uncertainty ◽  
Probabilistic Reinforcement ◽  
Hierarchical Bayesian Methods ◽  
Reinforcement Learning Models

In the real world, many relationships between events are uncertain and probabilistic. Uncertainty is also likely to be a more common feature of daily experience for youth because they have less experience to draw from than adults. Some studies suggest probabilistic learning may be inefficient in youths compared to adults, while others suggest it may be more efficient in youths in mid adolescence. Here we used a probabilistic reinforcement learning task to test how youth age 8-17 (N = 187) and adults age 18-30 (N = 110) learn about stable probabilistic contingencies. Performance increased with age through early-twenties, then stabilized. Using hierarchical Bayesian methods to fit computational reinforcement learning models, we show that all participants’ performance was better explained by models in which negative outcomes had minimal to no impact on learning. The performance increase over age was driven by 1) an increase in learning rate (i.e. decrease in integration time scale); 2) a decrease in noisy/exploratory choices. In mid-adolescence age 13-15, salivary testosterone and learning rate were positively related. We discuss our findings in the context of other studies and hypotheses about adolescent brain development.

scholarly journals Using reinforcement learning models in social neuroscience: frameworks, pitfalls and suggestions of best practices

2020 ◽  
Vol 15 (6) ◽  
pp. 695-707 ◽  
Author(s):  
Lei Zhang ◽  
Lukas Lengersdorff ◽  
Nace Mikus ◽  
Jan Gläscher ◽  
Claus Lamm
Keyword(s):  
Reinforcement Learning ◽  
Prediction Error ◽  
Model Comparison ◽  
Hierarchical Modeling ◽  
Learning Rate ◽  
Neural Activation ◽  
Affective Neuroscience ◽  
Outcome Valence ◽  
Practical Guidelines ◽  
Reinforcement Learning Models

Abstract The recent years have witnessed a dramatic increase in the use of reinforcement learning (RL) models in social, cognitive and affective neuroscience. This approach, in combination with neuroimaging techniques such as functional magnetic resonance imaging, enables quantitative investigations into latent mechanistic processes. However, increased use of relatively complex computational approaches has led to potential misconceptions and imprecise interpretations. Here, we present a comprehensive framework for the examination of (social) decision-making with the simple Rescorla–Wagner RL model. We discuss common pitfalls in its application and provide practical suggestions. First, with simulation, we unpack the functional role of the learning rate and pinpoint what could easily go wrong when interpreting differences in the learning rate. Then, we discuss the inevitable collinearity between outcome and prediction error in RL models and provide suggestions of how to justify whether the observed neural activation is related to the prediction error rather than outcome valence. Finally, we suggest posterior predictive check is a crucial step after model comparison, and we articulate employing hierarchical modeling for parameter estimation. We aim to provide simple and scalable explanations and practical guidelines for employing RL models to assist both beginners and advanced users in better implementing and interpreting their model-based analyses.

scholarly journals Feasibility Analysis and Application of Reinforcement Learning Algorithm Based on Dynamic Parameter Adjustment

Algorithms ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 239 ◽  
Author(s):  
Menglin Li ◽  
Xueqiang Gu ◽  
Chengyi Zeng ◽  
Yuan Feng
Keyword(s):  
Machine Learning ◽  
Reinforcement Learning ◽  
Learning Algorithm ◽  
Dynamic Parameter ◽  
Learning Rate ◽  
New Method ◽  
Practical Application ◽  
Learning Rates ◽  
Dynamic Parameter Adjustment ◽  
Reinforcement Learning Algorithm

Reinforcement learning, as a branch of machine learning, has been gradually applied in the control field. However, in the practical application of the algorithm, the hyperparametric approach to network settings for deep reinforcement learning still follows the empirical attempts of traditional machine learning (supervised learning and unsupervised learning). This method ignores part of the information generated by agents exploring the environment contained in the updating of the reinforcement learning value function, which will affect the performance of the convergence and cumulative return of reinforcement learning. The reinforcement learning algorithm based on dynamic parameter adjustment is a new method for setting learning rate parameters of deep reinforcement learning. Based on the traditional method of setting parameters for reinforcement learning, this method analyzes the advantages of different learning rates at different stages of reinforcement learning and dynamically adjusts the learning rates in combination with the temporal-difference (TD) error values to achieve the advantages of different learning rates in different stages to improve the rationality of the algorithm in practical application. At the same time, by combining the Robbins–Monro approximation algorithm and deep reinforcement learning algorithm, it is proved that the algorithm of dynamic regulation learning rate can theoretically meet the convergence requirements of the intelligent control algorithm. In the experiment, the effect of this method is analyzed through the continuous control scenario in the standard experimental environment of ”Car-on-The-Hill” of reinforcement learning, and it is verified that the new method can achieve better results than the traditional reinforcement learning in practical application. According to the model characteristics of the deep reinforcement learning, a more suitable setting method for the learning rate of the deep reinforcement learning network proposed. At the same time, the feasibility of the method has been proved both in theory and in the application. Therefore, the method of setting the learning rate parameter is worthy of further development and research.

scholarly journals Dissociation between asymmetric value updating and perseverance in human reinforcement learning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michiyo Sugawara ◽  
Kentaro Katahira
Keyword(s):  
Reinforcement Learning ◽  
Hybrid Model ◽  
Empirical Data ◽  
Choice Behavior ◽  
Learning Rate ◽  
Web Based ◽  
Learning Rates ◽  
Asymmetric Learning ◽  
Open Datasets ◽  
Key Parameter

AbstractThe learning rate is a key parameter in reinforcement learning that determines the extent to which novel information (outcome) is incorporated in guiding subsequent actions. Numerous studies have reported that the magnitude of the learning rate in human reinforcement learning is biased depending on the sign of the reward prediction error. However, this asymmetry can be observed as a statistical bias if the fitted model ignores the choice autocorrelation (perseverance), which is independent of the outcomes. Therefore, to investigate the genuine process underlying human choice behavior using empirical data, one should dissociate asymmetry in learning and perseverance from choice behavior. The present study addresses this issue by using a Hybrid model incorporating asymmetric learning rates and perseverance. First, by conducting simulations, we demonstrate that the Hybrid model can identify the true underlying process. Second, using the Hybrid model, we show that empirical data collected from a web-based experiment are governed by perseverance rather than asymmetric learning. Finally, we apply the Hybrid model to two open datasets in which asymmetric learning was reported. As a result, the asymmetric learning rate was validated in one dataset but not another.

scholarly journals A confidence-based reinforcement learning model for perceptual learning

2017 ◽  
Author(s):  
Matthias Guggenmos ◽  
Philipp Sterzer
Keyword(s):  
Reinforcement Learning ◽  
Perceptual Learning ◽  
Main Idea ◽  
Learning Rate ◽  
Learning Theories ◽  
Model Parameters ◽  
Prediction Errors ◽  
Model Case ◽  
External Feedback ◽  
Reinforcement Learn

AbstractIt is well established that learning can occur without external feedback, yet normative reinforcement learning theories have difficulties explaining such instances of learning. Recently, we reported on a confidence-based reinforcement learn-ing model for the model case of perceptual learning (Guggenmos, Wilbertz, Hebart, & Sterzer, 2016), according to which the brain capitalizes on internal monitoring processes when no external feedback is available. In the model, internal confidence prediction errors – the difference between current confidence and expected confidence – serve as teaching signals to guide learning. In the present paper, we explore an extension to this idea. The main idea is that the neural information processing pathways activated for a given sensory stimulus are subject to fluctuations, where some pathway configurations lead to higher confidence than others. Confidence prediction errors strengthen pathway configurations for which fluctuations lead to above-average confidence and weaken those that are associated with below-average con-fidence. We show through simulation that the model is capable of self-reinforced perceptual learning and can benefit from exploratory network fluctuations. In addition, by simulating different model parameters, we show that the ideal confidence-based learner should (i) exhibit high degrees of network fluctuation in the initial phase of learning, but re-duced fluctuations as learning progresses, (ii) have a high learning rate for network updates for immediate performance gains, but a low learning rate for long-term maximum performance, and (iii) be neither too under-nor too overconfident. In sum, we present a model in which confidence prediction errors strengthen favorable network fluctuations and enable learning in the absence of external feedback. The model can be readily applied to data of real-world perceptual tasks in which observers provided both choice and confidence reports.

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