The Two-Point Threshold

  title={The Two-Point Threshold},
  author={James C. Craig and Kenneth O. Johnson},
  journal={Current Directions in Psychological Science},
  pages={29 - 32}
  • J. Craig, K. Johnson
  • Published 1 February 2000
  • Psychology
  • Current Directions in Psychological Science
The two-point threshold, or compass test, has long been used as a measure of tactile spatial resolution; however, since it was first developed, there have been problems associated with its use. Some of these problems include setting an appropriate criterion for responding “two,” extreme variability both within and between subjects, and the ability of subjects to discriminate two points from one at separations well below the two-point threshold. Recent neurophysiological results have clarified… 
Two-Point Orientation Discrimination Versus the Traditional Two-Point Test for Tactile Spatial Acuity Assessment
It is concluded that the traditional two-point task provides an unintended non-spatial cue, resulting in spuriously good performance at small spatial separations, and is recommended for the use of two- point orientation discrimination for neurological assessment.
A quantitative method for determining spatial discriminative capacity
Results obtained from this study showed that the performance of the amplitude discrimination task was significantly degraded when the stimuli were delivered simultaneously and were near a subject's two-point limen, and subjects were able to correctly discriminate between the amplitudes when they were sequentially delivered at all inter-probe distances.
Tactile spatial acuity of the neck using a two-point orientation discrimination task
Results indicate that the neck could be a viable location to effectively communicate tactile information in a uniform fashion.
Two-point tactile discrimination ability is influenced by temporal features of stimulation
The results indicate that temporal features of tactile stimulation significantly influence sensory performance in a tactile spatial discrimination task and Precise control of temporal stimulus parameters should help to reduce variations in results on the two-point discrimination threshold.
Tactile Acuity Charts: A Reliable Measure of Spatial Acuity
A comparison with the two-point and grating orientation task data showed that the test-retest reliability of the acuity chart measurements after one week was superior to that of the passive methods, suggesting that tactile spatial resolution is a complex entity that should ideally be measured with different methods in parallel.
Vibrotactile Spatial Acuity and Intensity Discrimination on the Lower Back Using Coin Motors
This study has determined the two-point discrimination threshold and intensity-discrimination threshold (just-noticeable difference, or JND) on the lower back using coin motors and provides the predicted spatial resolution and contrast resolution achievable with a back-worn tactile display based on coin motors.
Temporal factors in tactile spatial acuity: evidence for RA interference in fine spatial processing.
The grating orientation threshold (GOT)-the spatial period at which subjects can reliably discriminate the orientation of the grating-increased as the vibratory frequency of the gratings increased, and adapting RA afferent fibers improved spatial acuity, as gauged by GOTs, at the high flutter frequencies.
Psychophysical Evaluation of a Tactile Display Based on Coin Motors
This study has tested the performance of a prototype 96-tactor vibrotactile using a subset of 64 tactors and determined the tactile spatial acuity and intensity discrimination in 14 naïve subjects.
Tactile co-activation improves detection of afferent spatial modulation
Findings indicate that the SM/GV task may be better suited than the GR/OR or 3-dot tasks for measuring changes in tactile sensitivity following co-activation, and that the latter requires only that spatial modulation in the afferent population be detected.
A comparison of tactile spatial sensitivity on the palm and fingerpad
  • J. Craig, K. Lyle
  • Environmental Science, Biology
    Perception & psychophysics
  • 2001
Performance of spatial tasks on the palm can be predicted quantitatively from fingerpad data with a moderate degree of accuracy, indicating that spatial patterns are processed similarly at the two sites.


The limit of tactile spatial resolution in humans
The grating orientation discrimination task provides a stable, reliable measure of the human capacity for spatial resolution, and psychophysical thresholds for tactile spatial resolution are obtained from 15 normal, young adult subjects over seven test sessions.
Spatial acuity of the body surface over the life span.
The main finding was that aging is much harder on some body regions than on others, and the hands and feet turned out to be far more vulnerable than the more central regions, including the very acute lip and tongue.
Handbook of perception and human performance
This handbook covers theory and methods; basic visual processes; auditory, kinesthetic, cutaneous, and vestibular senses; and space and motion perception; and human performance.
The Spatial Characteristics of Tactile Form Perception
The reversal phenomena observed in experiments, and in experiments of others which involve drawing characters on the skin, are consistent with Gibson's proposal that it is object form which is directly perceived, but that this involves interpretation of the patterns of skin stimulation within a framework of spatial coordinates.
Handbook of Perception and Human Performance. Volume 2. Cognitive Processes and Performance
This chapter has attempted to bring together the laboratory and field-based techniques currently in use to assess workload, particularly as they are used with computer models of whole missions or operations.
Surround suppression in the responses of primate SA1 and RA mechanoreceptive afferents mapped with a probe array.
A remarkable result is that the force-displacement relationships in humans and monkeys were the same; the skin is highly compliant for the first 2-3 mm of indentation and then becomes much stiffer and the compliant range substantially is reduced substantially.
A psychophysical study of the mechanisms of sensory recovery following nerve injury in humans.
The psychophysical findings in this study are consistent with neurophysiological data showing that the major primary afferent fibre classes reinnervate the skin at a similar rate.
E.H. Weber on the Tactile Senses
Part 1 "De Tactu": summa dotrinae de tactu main findings on the tactile senses. Part 2 "Tastsinn und Gemeingefuehl": on the conditions under which sensations are referred to external objects on the
Sensation and perception in the history of experimental psychology
Rather than enjoying a fine ebook taking into consideration a cup of coffee in the afternoon, on the other hand they juggled subsequent to some harmful virus inside their computer. sensation and