Research Article Open Access
Volume 1 | Issue 2 | DOI: https://doi.org/10.33696/mentalhealth.1.008

A New Adaptive Procedure for Estimating Perceptual Thresholds: The Effects of Observer Bias and Its Correction

  • 1MEG Center, University of Tübingen, Tübingen, Germany
  • 2Institute of Medical Psychology and Behavioral Neurobiology, Medical Faculty, University of Tübingen, Tübingen, Germany
  • 3Hertie Institute for Clinical Brain Research Neuroscience, University of Tübingen, Tübingen, Germany
  • 4CIMeC, Center for Mind/Brain Sciences Cognitive Neuroscience, University of Trento, Trento, Italy
  • 5 University Hospital Tübingen, Department of Psychiatry and Psychotherapy, Tübingen, Germany
  • 6Department of Psychiatry and Division of Neuroscience, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile
  • 7Laboratory for Brain-Machine Interfaces and Neuromodulation, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile
  • 8Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biology, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile
  • 9IMPRS-GTC, International Max-Planck Research School-Graduate Training Center for Neuroscience, Tübingen, Germany
  • 10Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, University Hospital Frankfurt and Goethe University, Frankfurt Am Main, Germany
  • 11LOEWE Center for Personalized Translational Epilepsy Research (CePTER), Goethe University, Frankfurt Am Main, Germany
+ Affiliations - Affiliations

Corresponding Author

Diljit Singh Kajal, diljitsingh.kajal@kgu.de

Received Date: August 08, 2021

Accepted Date: November 24, 2021


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 observer's 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 subject's sensitivity. This novel AM is validated with simulations and compared to a typical MCSprocedure, 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.


Adaptive procedure, Method of constant stimuli, Perception, Signal detection theory, Threshold estimation

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