E.H. Weber On The Tactile Senses

David J. Murray, Helen E. Ross, David J. Murray, Helen E. Ross, David J. Murray, Helen E. Ross, E.H Weber

• Publisher: Psychology Press
• Year: 2018
• ISBN:
  9781317707448
• Edition: 1
• Topic: Psychology
• Subtopic: History & Theory in Psychology
• Index: Psychology

This is a revised edition of "E.H. Weber: The Sense of Touch". The title has been broadened to reflect the fact that Weber explored all the skin senses - and indeed the muscle sense and that mysterious entity "the common feeling". The introduction has been expanded to include further information on Weber's life and times, and on recent research relevant to Weber's own work. The translations of Weber's main works of psychological interest "De Tactu" and "Der Tastsinn und das Gemeingefuehl" contain only minor changes, but the footnotes have been updated.; The reader will find here much more than those topics for which Weber is best known - the two-point threshold, experiments on weight discrimination, and a statement of what is now called Weber's Law. Weber also remarked on many aspects of sensory psychology - on left-right asymmetry in sensitivity, on visual resolution, the binocular combination of colours, the moon illusion, on summation, inhibition and adaptation in sensory systems, on the difference between simultaneous and successive presentations, on selective attention, the externalization of sensations and the difference between sensation and perception.

DE SUBTILITATE TACTUS

Facing Page: Title page of Weber’s collected works containing De Tactu, 1834.

DE PULSU, RESORPTIONE, AUDITU ET TACTU.

ANNOTATIONES ANATOMICAE ET PHYSIOLOGICAE

AUCTORE

ERNESTO HENRICO WEBER

ANATOMIAE PROFEISORE IN UNIVERSIT. LITCRARVM LIPSIENSI.

LIPSIAE

PROSTAT APUO C.F. KOEHLER.

1834.

WEBER’S INDEX TO DE TACTU

(This summary of contents appears on pp. VI-VIII of the original text. All page numbers refer to those of the original text.)

I. Experiments on tactile sensitivity, p. [44-145]

II. Final conclusions concerning the touch-sense, p. [145-168]

The sensations aroused in the touch organ are of two sorts: for we perceive (1) a certain pressure or traction (2) heat or cold; but in both cases the sensation seems to depend on some sort of pressure, p. [44 & 145].

On the correct perception of the place where we are touched.

Two objects touching the skin simultaneously seem to be separated by a smaller distance the less sensitive the touch-sense is in various parts of the skin, p. [45 & 147] - A phenomenon worth noting from that observation is explained, p. [59 & 148] - When two objects simultaneously touch the arms or legs along a line parallel to the longitudinal axis of a limb, they seem to us to be closer together than when they touch the limbs along the perimeter, p. [49 & 151] - The causes of this phenomenon, p. [151] - Two simultaneous impressions merge into one if the places touched are close enough together. We measure the sensitivity of the touch-sense by this distance, which is larger or smaller in different parts of the skin. A table containing experiments on this subject, p. [50] - A table showing the sensitivity of the touch-sense in different parts of the skin, represented as lines of various length: for the shorter the lines opposite the names of the parts, the more acute the touch-sense, p. [58].

If two contiguous and mobile parts are touched simultaneously, these parts are more clearly discriminated and seem farther apart than if one part is touched in two places simultaneously. If two parts of the skin are touched simultaneously we can discriminate them more easily if they are located opposite each other or if they differ in structure or use. p. [61] - In the skin, spots possessing a more acute touch-sense frequently seem to be placed next to those with a duller touch-sense. p. [62]. A strong impression obscures a less strong one. p. [62] - We discriminate impression more easily in turn, if we are not touched at precisely the same moment of time. p. [63] - The parts in the extremities that excel with the most acute touch-sense are shown in a way approved earlier, p. [63 & 157] -Which parts of the head excel in tactile sensitivity? p. [65 & 154] - Which parts of the trunk excel in tactile sensitivity? p. [67 & 155] - In many parts of the trunk two objects simultaneously touching the longitudinal line of the periphery of the trunk seem farther apart than when touching the transverse line; and this seems to depend on whether the course of the nerves is in a longitudinal or transverse direction, p. [68] - On the causes of tactile sensitivity, p. [75] - The touch-sense of the skin does not become more sensitive because we inspect part of the skin with the eyes, and in this way learn its arrangement and shape more accurately, p. [75] - Neither does sensitivity depend on the number and size of the papillae of the skin. p. [77] - Tactile sensitivity seems to depend instead on the number of nerves that terminate in a part of the skin. p. [77] - The touch-sense is much improved by voluntary movement p. [177] - With closed eyes and a stationary hand we can discriminate with difficulty, or not at all, between very different objects placed on our finger-tips. p. [80] - We do not perceive the direction in which objects press on the skin, but we recognize very accurately the direction in which the hairs are pulled: this is done not only by the sense of touch, but by that sense combined with the movement of the muscles when they resist the pull of the hairs, p. [78 & 158].

On the correct perception of the weight of objects.

The weight of objects is perceived in two ways: first by the touch-sense residing in the skin, and then by the sense belonging to the voluntary muscles, through which we recognise the degree of effort of the muscles in overcoming the weights and other obstacles, p. [81 & 159] - We do not perceive the value of the weights as clearly if the weights are placed on stationary and supported hands, as when they are weighed by our raised hands, p. [86, 134 & 159] - A certain weight on parts possessing a more acute touch-sense produces a sensation of stronger pressure, p. [94] - In those parts of the skin where we have the best tactile knowledge of the separation of the compass legs, a certain weight also produces a sensation of stronger pressure, p. [96 & 161] - A greater weight on a part of the skin possessing a blunter touch-sense arouses a similar sensation to that of a lesser weight on a part with a more acute touch-sense, p. [98] - All the organs of touch, even at their most sensitive, are very sluggish, p. [Ill] - For most people, a weight seems to make a greater impression when received by the left rather than by the right hand. p. [84].

On the correct perception of the temperature of objects.

On certain errors to which we are liable in perceiving temperature, p. [113] - In those parts where we have the best tactile knowledge of the separation of the compass legs and of the value of weights, we also perceive the temperature of objects most clearly: it may therefore be supposed that the temperature and pressure sense reside in the same part of the touch organ, p. [163] - Through the touch-sense we perceive a quantity of heat either subtracted from or added to the skin, when the latter is at a certain temperature, p. [113 & 166] -If the palm of the hand has a temperature of 29 or 29Vi degrees R., water of 29 degrees R. causes a sensation of heat, and water of 28 degrees R. a sensation of cold. p. [169] - The sensations of cold and heat differ from each other in a different way than the sensations of light and dark. p. [169] - A lesser degree of heat received by a greater skin surface arouses in us a similar sensation to a greater degree of heat acting on a smaller surface; for impressions from single particles of water made on different spots of the skin merge together into one stronger impression, p. [113 & 165] - The back of the hand, when immersed in water, is more quickly affected by heat or cold than the palm. For its thinner cuticle does not resist heat or cold as strongly as the thicker cuticle of the palm; but after heat or cold has penetrated the cuticle the sensation in the palm is stronger, because of the greater number of nerves, p. [121] - We recognise a temperature difference more clearly when a larger skin surface is touched by warm objects than when a smaller surface comes into contact with the same object, p. [165] - For most people, a hot or cold object arouses a sensation of greater heat or cold in the left hand than in the right. The sensation of burning is a subjective sensation depending on too great an irritation of the brain produced by heat: it arises partly if the degree of heat is too great, and partly if the area of the body simultaneously affected by heat is too large, p. [170] - The less the degree of heat and the smaller the body surface exposed to the heat, the longer the time interval that elapses before a sensation of burning arises, p. [127].

On the comparison of the touch-sense with other senses.

The weights of two objects are more easily compared and more accurately discriminated in turn, if they are weighed by hand successively rather than simultaneously; the same is true of the discrimination of the temperature of objects, which are distinguished more clearly when perceived successively. The other senses are also subject to the same rule. p. [120 & 166] - The reason is that a sensation merges with another sensation when simultaneous, and is confused with it, and so is perceived less clearly and is discriminated less well. Therefore we compare a past sensation with a present one more accurately than two present sensati...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication Page
• Contents
• Preface to the First Edition
• Preface to the Second Edition
• Acknowledgements
• INTRODUCTION
• De Tactu
• Tastsinn Und Gemeingefühl
• Indexes