Guggenmos, M. | bioRxiv Science

bioRxiv2021

Reverse engineering of metacognition

The human ability to introspect on thoughts, perceptions or actions - metacognitive ability - has become a focal topic of both cognitive basic and clinical research. At the same time it has become increasingly clear that currently available quantitative tools are limited in their ability to make unconfounded inferences about metacognition. As a step forward, the present work introduces a comprehensive modeling framework of metacognition that allows for inferences about metacognitive noise and metacognitive biases during the readout of decision values or at the confidence reporting stage. The model assumes that confidence results from a continuous but noisy and potentially biased transformation of decision values, described by a confidence link function. A canonical set of metacognitive noise distributions is introduced which differ, amongst others, in their predictions about metacognitive sign flips of decision values. Successful recovery of model parameters is demonstrated, and the model is validated on an empirical data set. In particular, it is shown that metacognitive noise and bias parameters correlate with conventional behavioral measures. Crucially, in contrast to these conventional measures, metacognitive noise parameters inferred from the model are shown to be independent of performance. This work is accompanied by a toolbox (ReMeta) that allows researchers to estimate key parameters of metacognition in confidence datasets.

systems biology↗

bioRxiv2017

A Confidence-Based Reinforcement Learning Model For Perceptual Learning

It 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.

neuroscience↗