scholarly journals How reinforcement shapes the binding of stimulus-control associations

2020 ◽  
Author(s):  
Christina Bejjani ◽  
Tobias Egner

Cognitive control describes the ability to use internal goals to strategically guide how we process and respond to our environment. Changes in the environment lead to adaptation in control strategies. This type of control-learning can be observed in performance adjustments in response to varying proportions of easy to hard trials over blocks of trials on classic cognitive control tasks. Known as the list-wide proportion congruent (LWPC) effect, here, increased difficulty is met with enhanced attentional control. Recent research has shown that reinforcement events, in the form of performance feedback, enhance the LWPC effect, but the underlying mechanisms are not yet understood. To assess different hypotheses of how feedback is processed in the LWPC, we manipulated proportion congruency in a Stroop task over blocks of trials and provided trial-by-trial task-relevant word and task-irrelevant, trial-unique image performance feedback. The LWPC task was followed by a surprise recognition memory task for feedback images, which allowed us to test whether attention to feedback (incidental memory for the images) varies as a function of proportion congruency, time, and individual differences in reward sensitivity. We replicated a robust LWPC effect. Importantly, the memory data revealed better encoding of feedback images from context-defining trials (e.g., congruent trials in a mostly congruent block), especially early on in a new context, and in congruent conditions. Individual differences in reward sensitivity were not strongly associated with control-learning effects. These results suggest that reinforcement promotes the rapid forming of associations between stimuli and control demands, or context binding.

2019 ◽  
Author(s):  
Christina Bejjani ◽  
Sophie Tan ◽  
Tobias Egner

Cognitive control refers to the use of internal goals to guide how we process stimuli, and control can be applied proactively (in anticipation of a stimulus) or reactively (once that stimulus has been presented). The application of control can be guided by memory; for instance, people typically learn to adjust their level of attentional selectivity to changing task statistics, such as different frequencies of hard and easy trials in the Stroop task. This type of “control-learning” is highly adaptive, but its boundary conditions are currently not well understood. In the present study, we assessed how the presence of performance feedback shapes control-learning in the context of item-specific (reactive control, Experiments 1a and 1b) and list-wide (proactive control, Experiments 2a and 2b) proportion of congruency manipulations in a Stroop protocol. We found that performance feedback did not alter the modulation of the Stroop effect by item-specific cueing, but did enhance the modulation of the Stroop effect by a list-wide context. Performance feedback thus selectively promoted proactive, but not reactive, adaptation of cognitive control. These results have important implications for experimental designs, potential psychiatric treatment, and theoretical accounts of the mechanisms underlying control-learning.


2020 ◽  
Author(s):  
Daniel Poremski ◽  
Sandra Henrietta Subner ◽  
Grace Lam Fong Kin ◽  
Raveen Dev Ram Dev ◽  
Mok Yee Ming ◽  
...  

The Institute of Mental Health in Singapore continues to attempt to prevent the introduction of COVID-19, despite community transmission. Essential services are maintained and quarantine measures are currently unnecessary. To help similar organizations, strategies are listed along three themes: sustaining essential services, preventing infection, and managing human and consumable resources.


1989 ◽  
Vol 24 (3) ◽  
pp. 463-477
Author(s):  
Stephen G. Nutt

Abstract Based on discussions in workshop sessions, several recurring themes became evident with respect to the optimization and control of petroleum refinery wastewater treatment systems to achieve effective removal of toxic contaminants. It was apparent that statistical process control (SPC) techniques are finding more widespread use and have been found to be effective. However, the implementation of real-time process control strategies in petroleum refinery wastewater treatment systems is in its infancy. Considerable effort will need to be expended to demonstrate the practicality of on-line sensors, and the utility of automated process control in petroleum refinery wastewater treatment systems. This paper provides a summary of the discussions held at the workshop.


Author(s):  
Ivan Herreros

This chapter discusses basic concepts from control theory and machine learning to facilitate a formal understanding of animal learning and motor control. It first distinguishes between feedback and feed-forward control strategies, and later introduces the classification of machine learning applications into supervised, unsupervised, and reinforcement learning problems. Next, it links these concepts with their counterparts in the domain of the psychology of animal learning, highlighting the analogies between supervised learning and classical conditioning, reinforcement learning and operant conditioning, and between unsupervised and perceptual learning. Additionally, it interprets innate and acquired actions from the standpoint of feedback vs anticipatory and adaptive control. Finally, it argues how this framework of translating knowledge between formal and biological disciplines can serve us to not only structure and advance our understanding of brain function but also enrich engineering solutions at the level of robot learning and control with insights coming from biology.


Water Policy ◽  
2014 ◽  
Vol 17 (3) ◽  
pp. 423-440 ◽  
Author(s):  
Lei Wu ◽  
Tong Qi ◽  
Dan Li ◽  
Huijuan Yang ◽  
Guoqing Liu ◽  
...  

The surface water of 10 major river systems across China has been under intermediate pollution with striking eutrophication problems in major lakes (reservoirs). More data from the Ministry of Environmental Protection of China showed that underground water in 57% of monitoring sites across Chinese cities was polluted or extremely polluted. Rural water pollution, the rising number of incidents of industrial pollution, outdated sewerage systems, and the overuse of pesticides and chemical fertilizers also endanger the health of rural inhabitants in China. Nearly 0.2 billion rural residents could not use drinking water in accordance with the national standard, and there were reports of ‘cancer villages' and food-borne diseases (cancer village refers to a village where a certain proportion of its inhabitants suffer from the same kind of cancer or where there is a hike in cancer incidence in that area). This study aims to raise awareness of the prevention and control of water pollution and to propose a set of national research and policy initiatives for the future safety of the water environment in China.


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