A new adaptive procedure for estimating perceptual thresholds: the effects of observer bias and its correction.

Adaptive threshold estimation procedures sample close to a subject's perceptual threshold by dynamically adapting the stimulation based on the subject's performance. Yet, perceptual thresholds not only depend on the observers' sensory capabilities but also on any bias in terms of their expectations and response preferences, thus distorting the precision of the threshold estimates. Using the framework of signal detection theory (SDT), independent estimates of both, an observer's sensitivity and internal processing bias can be delineated from threshold estimates. While this approach is commonly available for estimation procedures engaging the method of constant stimuli (MCS), correction procedures for adaptive methods (AM) are only scarcely applied. In this article, we introduce a new AM that takes individual biases into account, and that allows for a bias-corrected assessment of subjects' sensitivity. This novel AM is validated with simulations and compared to a typical MCS-procedure, for which the implementation of bias correction has been previously demonstrated. Comparing AM and MCS demonstrates the viability of the presented AM. Besides its feasibility, the results of the simulation reveal both, advantages, and limitations of the proposed AM. The procedure has considerable practical implications, in particular for the design of shaping procedures in sensory training experiments, in which task difficulty has to be constantly adapted to an observer's performance, to improve training efficiency.

First Language Attrition on Prosody in a Foreign Language Environment

In this study, we explore whether first language (L1) attrition affects the use of prosodic cues in anaphora resolution. 18 late Italian–Swedish bilinguals completed a speech production task in L1 Italian, wherein we measured the inter-clausal pause duration and the pronoun’s degree of prosodic prominence. They also completed a control interpretation task, wherein we analysed response preferences, to test the status of L1 attrition on anaphora resolution when sentences are not vocalized. Prominence patterns and pause features exhibited by the late bilinguals were compared to those shown by Italian and Swedish monolinguals investigated in a previous study in 2019. The results suggest L1 attrition to affect the use of prosodic cues in anaphora resolution. The attrition rate was influenced by length of residence (LoR): the longer the residence in the foreign language (FL) environment, the higher the probability of adaptation to the FL prominence patterns, for most of the prosodic cues.

The European Stability Mechanism and the IMF: From the Enhanced Cooperation to Embedded Supervisor

This paper examines the role played by the International Monetary Fund (IMF) in the European Stability Mechanism (ESM), finding that the ESM has greatly expanded the IMF’s surveillance and oversight roles in the European Monetary Union (EMU). Building from a liberal intergovernmental framework of integration analysis, this paper argues that the IMF’s function as a de facto EMU supervisor in the ESM, a significant break from prior European integration, stems from the alignment of crisis response preferences amongst the EMU’s largest economies, the erosion of the credibility of the European Commission as an enforcer of structural reforms, and the IMF’s close fit with the preferred institutional arrangements that derived from the bargaining dynamics between euro members. Full text available at: https://doi.org/10.22215/rera.v12i1.1232

The European Stability Mechanism and the IMF: From the Enhanced Cooperation to Embedded Supervisor

This paper examines the role played by the International Monetary Fund (IMF) in the European Stability Mechanism (ESM), finding that the ESM has greatly expanded the IMF’s surveillance and oversight roles in the European Monetary Union (EMU). Building from a liberal intergovernmental framework of integration analysis, this paper argues that the IMF’s function as a de facto EMU supervisor in the ESM, a significant break from prior European integration, stems from the alignment of crisis response preferences amongst the EMU’s largest economies, the erosion of the credibility of the European Commission as an enforcer of structural reforms, and the IMF’s close fit with the preferred institutional arrangements that derived from the bargaining dynamics between euro members.

Adjudicating between face-coding models with individual-face fMRI responses

The perceptual representation of individual faces is often explained with reference to a norm-based face space. In such spaces, individuals are encoded as vectors where identity is primarily conveyed by direction and distinctiveness by eccentricity. Here we measured human fMRI responses and psychophysical similarity judgments of individual face exemplars, which were generated as realistic 3D animations using a computer-graphics model. We developed and evaluated multiple neurobiologically plausible computational models, each of which predicts a representational distance matrix and a regional-mean activation profile for 24 face stimuli. In the fusiform face area, a face-space coding model with sigmoidal ramp tuning provided a better account of the data than one based on exemplar tuning. However, an image-processing model with weighted banks of Gabor filters performed similarly. Accounting for the data required the inclusion of a measurement-level population averaging mechanism that approximates how fMRI voxels locally average distinct neuronal tunings. Our study demonstrates the importance of comparing multiple models and of modeling the measurement process in computational neuroimaging.Author SummaryHumans recognize conspecifics by their faces. Understanding how faces are recognized is an open computational problem with relevance to theories of perception, social cognition, and the engineering of computer vision systems. Here we measured brain activity with functional MRI while human participants viewed individual faces. We developed multiple computational models inspired by known response preferences of single neurons in the primate visual cortex. We then compared these neuronal models to patterns of brain activity corresponding to individual faces. The data were consistent with a model where neurons respond to directions in a high-dimensional space of faces. It also proved essential to model how functional MRI voxels locally average the responses of tens of thousands of neurons. The study highlights the challenges in adjudicating between alternative computational theories of visual information processing.

How to train a neuron

A cellular learning rule known as spike-timing-dependent plasticity can form, reshape and erase the response preferences of visual cortex neurons.