A critical experimental study of the classical tactile threshold theory

<p>Abstract</p> <p>Background</p> <p>The tactile sense is being used in a variety of applications involving tactile human-machine interfaces. In a significant number of publications the classical threshold concept plays a central role in modelling and explaining psychop...

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Main Authors: Medina Leonel E, Donoso José R, Perez Claudio A
Format: Article
Language:English
Published: BMC 2010-06-01
Series:BMC Neuroscience
Online Access:http://www.biomedcentral.com/1471-2202/11/76
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spelling doaj-7a25143a29f949aebaf040ccc250aada2020-11-24T21:52:07ZengBMCBMC Neuroscience1471-22022010-06-011117610.1186/1471-2202-11-76A critical experimental study of the classical tactile threshold theoryMedina Leonel EDonoso José RPerez Claudio A<p>Abstract</p> <p>Background</p> <p>The tactile sense is being used in a variety of applications involving tactile human-machine interfaces. In a significant number of publications the classical threshold concept plays a central role in modelling and explaining psychophysical experimental results such as in stochastic resonance (SR) phenomena. In SR, noise enhances detection of sub-threshold stimuli and the phenomenon is explained stating that the required amplitude to exceed the sensory threshold barrier can be reached by adding noise to a sub-threshold stimulus. We designed an experiment to test the validity of the classical vibrotactile threshold. Using a second choice experiment, we show that individuals can order sensorial events below the level known as the classical threshold. If the observer's sensorial system is not activated by stimuli below the threshold, then a second choice could not be above the chance level. Nevertheless, our experimental results are above that chance level contradicting the definition of the classical tactile threshold.</p> <p>Results</p> <p>We performed a three alternative forced choice detection experiment on 6 subjects asking them first and second choices. In each trial, only one of the intervals contained a stimulus and the others contained only noise. According to the classical threshold assumptions, a correct second choice response corresponds to a guess attempt with a statistical frequency of 50%. Results show an average of 67.35% (STD = 1.41%) for the second choice response that is not explained by the classical threshold definition. Additionally, for low stimulus amplitudes, second choice correct detection is above chance level for any detectability level.</p> <p>Conclusions</p> <p>Using a second choice experiment, we show that individuals can order sensorial events below the level known as a classical threshold. If the observer's sensorial system is not activated by stimuli below the threshold, then a second choice could not be above the chance level. Nevertheless, our experimental results are above that chance level. Therefore, if detection exists below the classical threshold level, then the model to explain the SR phenomenon or any other tactile perception phenomena based on the psychophysical classical threshold is not valid. We conclude that a more suitable model of the tactile sensory system is needed.</p> http://www.biomedcentral.com/1471-2202/11/76
collection DOAJ
language English
format Article
sources DOAJ
author Medina Leonel E
Donoso José R
Perez Claudio A
spellingShingle Medina Leonel E
Donoso José R
Perez Claudio A
A critical experimental study of the classical tactile threshold theory
BMC Neuroscience
author_facet Medina Leonel E
Donoso José R
Perez Claudio A
author_sort Medina Leonel E
title A critical experimental study of the classical tactile threshold theory
title_short A critical experimental study of the classical tactile threshold theory
title_full A critical experimental study of the classical tactile threshold theory
title_fullStr A critical experimental study of the classical tactile threshold theory
title_full_unstemmed A critical experimental study of the classical tactile threshold theory
title_sort critical experimental study of the classical tactile threshold theory
publisher BMC
series BMC Neuroscience
issn 1471-2202
publishDate 2010-06-01
description <p>Abstract</p> <p>Background</p> <p>The tactile sense is being used in a variety of applications involving tactile human-machine interfaces. In a significant number of publications the classical threshold concept plays a central role in modelling and explaining psychophysical experimental results such as in stochastic resonance (SR) phenomena. In SR, noise enhances detection of sub-threshold stimuli and the phenomenon is explained stating that the required amplitude to exceed the sensory threshold barrier can be reached by adding noise to a sub-threshold stimulus. We designed an experiment to test the validity of the classical vibrotactile threshold. Using a second choice experiment, we show that individuals can order sensorial events below the level known as the classical threshold. If the observer's sensorial system is not activated by stimuli below the threshold, then a second choice could not be above the chance level. Nevertheless, our experimental results are above that chance level contradicting the definition of the classical tactile threshold.</p> <p>Results</p> <p>We performed a three alternative forced choice detection experiment on 6 subjects asking them first and second choices. In each trial, only one of the intervals contained a stimulus and the others contained only noise. According to the classical threshold assumptions, a correct second choice response corresponds to a guess attempt with a statistical frequency of 50%. Results show an average of 67.35% (STD = 1.41%) for the second choice response that is not explained by the classical threshold definition. Additionally, for low stimulus amplitudes, second choice correct detection is above chance level for any detectability level.</p> <p>Conclusions</p> <p>Using a second choice experiment, we show that individuals can order sensorial events below the level known as a classical threshold. If the observer's sensorial system is not activated by stimuli below the threshold, then a second choice could not be above the chance level. Nevertheless, our experimental results are above that chance level. Therefore, if detection exists below the classical threshold level, then the model to explain the SR phenomenon or any other tactile perception phenomena based on the psychophysical classical threshold is not valid. We conclude that a more suitable model of the tactile sensory system is needed.</p>
url http://www.biomedcentral.com/1471-2202/11/76
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