How to Measure Mind E-Book

• Herausgeber: Hogrefe Publishing
• Kategorie: Geisteswissenschaft
• Sprache: Englisch
• Veröffentlichungsjahr: 2022

Seitenzahl: 314

Beschreibung

Get to grips with the debate around the historical epistemological origins of psychometric assessment Written by leading experts Explores modern and historical aspects Full of illustrations A thoughtful look at the history of psychological assessment While there have been significant developments in the technical aspects of assessing mental functioning, there is still much to be debated about the motivations and meanings of measuring the mind. How can mental faculties be objectified and what influence does subjectivity have on the object being measured and the mind measuring it? What are the consequences of quantifying complex and interdependent functions and scaling these measurements for psychometric instruments? The contributors of this edited volume explore these questions by adopting a historical and epistemological approach to consider how psychometric assessment was born and developed within the affirmation of psychology as an empirical science. Chapters explore the birth of the scientific approach, as well as different assessment methods of cognitive abilities and personality traits, and the development of new technologies that support psychological evaluation and its applications in educational and rehabilitative fields. This book is of interest to researchers of human behavior as well as practicing psychologists and psychiatrists who want to deepen their understanding of the historical and epistemological roots of psychological assessment.

Leseprobe

Santo Di Nuovo

Maria Sinatra

(Editors)

How to Measure Mind

A Historical and Epistemological Approach to Psychological Assessment

Library of Congress Cataloging in Publication information for the print version of this book is available via the Library of Congress Marc Database under the LC Control Number 2022941738

Library and Archives Canada Cataloguing in Publication

Title: How to measure mind : a historical and epistemological approach to psychological assessment

/ Santo Di Nuovo, Maria Sinatra (eds.).

Names: Di Nuovo, Santo, editor. | Sinatra, Maria, editor.

Description: Includes bibliographical references.

Identifiers: Canadiana (print) 20220395519 | Canadiana (ebook) 20220395535 | ISBN 9780889375871

(softcover) | ISBN 9781616765873 (PDF) | ISBN 9781613345870 (EPUB)

Subjects: LCSH: Psychometrics—History. | LCSH: Psychological tests—History.

Classification: LCC BF39 .H69 2023 | DDC 150.28/7—dc23

© 2023 by Hogrefe Publishing

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ISBN 978-0-88937-587-1 (print) • ISBN 978-1-61676-587-3 (PDF) • ISBN 978-1-61334-587-0 (EPUB)

https://doi.org/10.1027/00587-000

Citability: This EPUB includes page numbering between two vertical lines (Example: |1|) that corresponds to the page numbering of the print and PDF ebook versions of the title.

Contents

Preface

Chapter 1  Examining the Subject-Object Relation in the Foundation of Scientific Psychology

Introduction

The First Steps Toward the Objectification of the Psychological Subject

The Error as the Landmark of the Measured Mind

How to Measure the Mind: The Objectification of Mental Processes

Helmoltzian Sensory Psychology and the Subject–Object Relationship

Can the Subject Be Investigated Subjectively? From Brentano to Fechner via Donders

Conclusion

Chapter 2  The Development of Applied Psychology and Psychotechnics in Germany: The Contributions of Walther Moede

Introduction

The Development of Psychotechnics: Walther Moede

Moede from Experimental to Applied Psychologist: The Role of Psychotechnics

Psychometric Tests for Drivers

From Educational to Industrial Psychology

Critical Issues Within Psychotechnics

Moede’s International Contacts Within Psychotechnics

Moede’s Role in the History of Psychotechnics (and Psychology)

Chapter 3  Wundtian Objects: The Paradigm of Self-Observation

Introduction

Psychology as Viewed by Positivists

Early Efforts at Methodologizing Psychology

Why Quantify Mental Events

Psychological Objects

Reality as Subject and Object

Chapter 4  Psychometrics: From the Past to the Present

The Early “Reactive” Psychological Instruments

Attempts to Measure Intelligence: From Mental Age to IQ, Including Criticisms

Testing in the United States: Enthusiasms and Debates

Measuring Intelligence Drives Us to Think About Intelligence

The Sense of Measuring

Beyond the Limits of “Objective” Psychometrics: Qualitative and Dynamic Assessment

The “Criterial” Tests

“Objective” Measurement of Personality: The Inventories

The (So-Called) “Projective” Tests

An Attempt at Synthesis: Is a Test an “Objective” Evaluation Tool?

Chapter 5  In-Depth Interviews: Self-Observation and the Emergence of Psychic Reality in Morphological Psychology

Subjectivity and Objectivity, Qualitative and Quantitative

Self-Observation: Restriction or Extension of the Perspective on the Psyche?

Artificial Conditions for the Reconstruction of Meaning Connections

The Use of Self-Observation in Morphological Psychology

The Morphological In-Depth Interview

Concrete Forms of Self-Observation in Morphological Investigations

Chapter 6  The New Frontiers of Psychometrics: From Computerized Adaptive Testing to the Use of Artificial Agents and E-Assessment

The Introduction of Computerization in Diagnosis: Advantages and Limitations

“Adaptive” Testing

Can Robotics Help With Psychometric Testing?

Electronic Testing: Lessons From the Pandemic

Chapter 7  From Subject to Object and Vice Versa: Activities of and in E-Learning

Introduction

The Theoretical Background

Educational Online Activities: Reshaping the Subject–Object Relationship

Evaluation and Assessment Within E-Learning Activities

References

Contributors

Peer Commentaries

|IX|Preface

In 1981, in his book The Mismeasure of Man, Jay Gould outlined two main errors in the measurement of human mental faculties: reification, i.e., the tendency to treat abstract concepts as objective entities, and forced ranking, i.e., ordering the variations of complex issues on a gradual scale. The measurement of the intellectual quotient (IQ) is the core example of these scientific fallacies, with both social (e.g., racism) and applicative consequences.

Since the publication of that critical and controversial book, the measurement of mental functions has made significant technical progress. Many relevant advances in psychometrics have overcome shortcomings in the reliability of assessment instruments. Not as much progress has been gained, however, from debates surrounding the motivation and the meaning of measuring the mind. We still have to deal with the theoretically defined problem of the objectification of mental faculties (e.g., intelligence, personality, adaptation) – and with the difficulties arising from the influence of subjectivity both on the object being measured and the mind measuring it. In addition, the question remains: What are the consequences of measuring complex and interdependent functions and scaling these measurements for psychometric instruments?

The prevailing methods in laboratory research – to which psychotechnics were linked from the beginning – are inadequate for analyzing the phenomena that occur in contexts in which means to control the intervening variables are limited and the measurement error strongly increases, for example, with the assessment in fields such as neuropsychological rehabilitation, education, and training, social and organizational psychology, clinical psychology, and psychotherapy. In these fields, many of the measurement instruments, although technically reliable, have less external validity than necessary for applicative purposes. How can we preserve objectivity in such fields of psychological measurement? Can new technologies help to tackle this old challenge?

Our collective work about the measurement of mind does not focus on the “how,” i.e., the technical aspects of psychological assessment and testing, which have been well treated in many textbooks, nor on listing the countless instruments available, whose constantly updated information is better found online in the catalogs of publishing houses.

The authors of this book approach their subjects from their respective different theoretical and experiential backgrounds, while also referring to their national traditions; they take a general perspective to explore the “why,” i.e., the meaning behind measuring mental functions using psychotechnics. They adopt a historical and epistemological approach and con|X|sider how measuring the mind was born and developed within the affirmation of psychology as an empirical science. The main question addressed in the book is thus: Can subjectivity be assessed using an (allegedly) objective methodology and psychometric techniques?

The topics cover the debate between objectification and subjectivity, present from the very beginning of the history of psychology and persisting – though often little considered – in contemporary methodology. This debate applies to both laboratory techniques and the psychometric tests initially derived from them. Why, and to what extent, is testing a part of experimental psychology? To successfully use tests within it, we must evaluate their epistemological boundaries and the possible developments, including those recently linked to artificial intelligence. We consider the different assessment methods of cognitive and personality aspects and the purposes leading to their detection and modification over time. We devote attention to new technologies suitable to supporting psychological evaluation and its applications in the educational and rehabilitative field. Maria Sinatra’s introductory chapter reaches back to the birth of scientific psychology, furthering the implications of the subject-object relation in pre-Wundtian times.

Horst Gundlach’s contribution summarizes the development of psychotechnics in Germany in the 19th century, focusing on the figure and the work of Walther Moede, a pioneer in this field, to exemplify some problems and conflicts that exist to the present day in the measurement of psychological functions outside the laboratory.

Luigi Traetta deals with the experimental techniques used in Wilhelm Wundt’s laboratory to understand the epistemological reasons underlying the dual concept of the observer and the observed as well as the issue of observing the self as an object.

Santo Di Nuovo retraces the history and methods of psychometric tests from the early instruments to the present advancements, discussing the alleged objectivity of measuring the mind through psychological testing. The question remains: How to assure an objective assessment of subjectivity in psychological research and applications?

Herbert Fitzek addresses the methodological question from a qualitative point of view, thus explaining the role played by in-depth interviews in their relationship with self-observation in morphological psychology.

Alessandro Di Nuovo and Daniela Conti expose the new frontiers of psychometrics, i.e., how artificial intelligence can help to build computerized adaptive testing, and to what extent artificial agents may be suitable in psychological assessment.

Finally, the chapter by Pierpaolo Limone presents the intriguing journey “from subject to object and vice versa” in the processes and techniques of e-learning evaluation, outlining both the history and epistemology of eval|XI|uation aimed at educational goals, which form the grounds for establishing suitable e-learning procedures so common during the current pandemic.

We hope that the book will be useful to scholars who want to deepen their understanding of the historical and epistemological roots of psychological assessment as well as to psychologists who want to rediscover the role of psychotechnics in their professional practice.

Santo Di Nuovo and Maria Sinatra

|1|Chapter 1Examining the Subject-Object Relation in the Foundation of Scientific Psychology

Maria Sinatra

Introduction

Wilhelm Wundt is best remembered for the 1879 foundation of the first laboratory of experimental psychology and thus for enabling psychology to enter the realm of scientific sciences as an institutionalized science for measuring the mind. However, despite the abundant historiographical research into his work (e.g., Danziger, 1990), what actually took place in that laboratory, together with all the factors that facilitated or hindered it, from Leibnizian thinking to the approaches of Helmholtz and Fechner, is to date less well explored (Fahrenberg, 2012, p. 228). A more detailed investigation of the second issue in particular could facilitate our understanding of how Wundt, who defined psychology as an empirical Geisteswissenschaft [humanities] and therefore placed himself at the crossroads of neurophysiology, psychology, and philosophy – albeit without adhering to any epistemological schools such as idealism, materialism, and positivism – must be well interpreted to clarify the meaning of the passage from body to mind. It is no coincidence that Wundt developed the concept of a monistically oriented “psychophysical parallelism,” whose roots involve the coordination of both causal and teleological analysis (i.e., the principle of cause, related to natural sciences) and the principle of purpose (related to mental sciences) and can be traced back to the law of sufficient reason first individualized by Leibniz. To this end, it is interesting to explore how medieval dualism as a metaphysical doctrine of two independently existing worlds – the world of spirit and the world of matter, the soul and the body – was transformed into dualism merely as a method, that is, as an epistemological dualism or psychophysical parallelism between knowing and the knower.

Thus, we should approach the Wundtian empirical perspective concerning what came before it, specifically in the 18th and 19th centuries. Further, while psychology has often been interpreted epistemologically, starting from its subdivision into contrasting and competing currents such as behavior|2|ism vs. gestaltism, experimental psychology vs. clinical psychology, etc. (e.g., Jovanović, 2010; Leary, 1994; Spaulding, 2013; Toomela, 2007; Valsiner, 1986), there is still little historiographical literature, especially regarding internal history, since history or medical history manuals often merely report external events (e.g., Bynum, 1994; Mosse, 1988). The following pages seek to answer Valsiner’s question: “Where is the individual subject in scientific psychology?” (Valsiner, 1986, p. 1). In other words, how was mind possible in a wholly physical world?

The First Steps Toward the Objectification of the Psychological Subject

In 1903, the ethologist and psychologist Conwy Lloyd Morgan wrote the following:

We speak of mind and matter, of self and not-self, of subject and object. What are the relationships involved in these antithetical concepts? […] Taking first the relation of subject and object we shall find it most convenient to begin by considering the impression as a product of sense-experience. Let us suppose that a puppy has an impression of a bone. For the puppy there is neither object nor subject, there is merely the impression as a bit of real vivid experience. But we, who wish to explain the puppy’s impression, submit it to analysis. And in the conceptual field of our thought it becomes […] polarized. At one pole there is the objective bone, and at the other pole the subjective consciousness of the puppy. We may then […] explain the impression “bone” in two ways. We may say:- There is an object in consciousness; or we may say:-There is a consciousness of the object. These are merely different modes of expressing the same fact of experience. But the former gives emphasis to the objective side of the impression, the latter to its subjective or conscious side. (Morgan, 1903, p. 312)

Morgan’s approach to the question, to which he dedicated the whole 17th chapter of his volume An Introduction to Comparative Psychology (Morgan, 1903, pp. 309 – 326), clearly showed how the terms subject and object, which were originally philosophical and went to Descartes’ epistemological dualism between res cogitans and res extensa, were used in the psychological realm in the last decades of the 19th century with the meaning of soul/mind and body/matter and, not the least, in the contrasting methodological dualism between the Geisteswissenschaften [humanities] and the Naturwissenschaften [natural sciences].

The first steps of this transition become visible in the initial attempts to make psychology a scientific discipline by detaching it from the philosophical field. Indeed, in 1756, Johann Gottlob Krüger, Professor of Medicine and Philosophy at the University of Helmstedt (Germany), expressed him|3|self in these terms in his Versuch einer Experimental-Seelenlehre [Proposal for an Experimental Doctrine of the Soul]:

Experiments can only be carried out with bodies. And if it would be possible […] to see the […] shapes [of the spirits] through magnifying glasses and weigh their forces? […] The error lies in the fact that, while carrying out experiments with the soul, one guesses he must use no instruments other than those that can be found in the scientific laboratory of a researcher of natural sciences. In my opinion, we should rather come to a conclusion according to which if the soul is very different from what is observed in natural sciences, then, very different experiments should be carried out with it. (Krüger, 1756, pp. 1 – 2)

This passage confirms the accuracy of Traxel’s observation that titles like Empirische Psychologie [Empirical Psychology], Seelenlehre [Doctrine of the Soul], or Erfahrungsseelenkunde [Empirical Psychology], signifying attempts to scientifically measure mental events and therefore to show the relationship of the soul with the body, were already widespread before 1850, and that psychology can therefore be considered to have been a well-established science before the model developed by its Founding Father, Wilhelm Maximilian Wundt (Traxel, 1995, p. 24), became widespread.

Moreover, Krüger’s observations confirm that, although the Aristotelian theory of the soul as the substantial form of the body was rejected in the 18th century, the Aristotelian conception of physics as the science of nature in general – including the human mind – was still very much alive.

Another significant example of such attempts made in the 18th and 19th centuries to investigate experimentally soul phenomena in terms of objects was the publication of the Magazin für Erfahrungsseelenkunde als ein Lesebuch für Gelehrte und Ungelehrte [Journal of Empirical Psychology, Reading for Scholars and Laymen]. Started in 1783 in Berlin and terminated in 1793 (Moritz, 1782) because of the early death of its founder, Karl Philipp Moritz, a pietistic traveler who defined psychology as a “science, and also an important one,” the journal was the first German periodical devoted exclusively to psychological issues, containing psychiatric observations, essays on cognitive processes, stories of dreams, and autobiographies (Dessoir, 1902, p. 154; Förstl et al., 1992).

However, it should be remembered that the inventor of the notion of empirical psychology was in fact not Moritz but the philosopher Christian Wolff, who classed psychology under metaphysics and distinguished between psychologia empirica and psychologia rationalis. Envisaging their integration with different “openings,” he saw the combined experientia and ratio in the work of the psychologist who, just like the astrologer, observes and theorizes (Wolff, 1732/1983, p. 3): The nomothetic and idiographic approaches to knowledge, later introduced into psychology by the neo-Kantian philosopher Wilhelm Windelband, were about to emerge.

|4|As for Moritz’s project, in 1798 the English psychiatrist Alexander Crichton commented on the rubric concerning the Seelenkrankheitskunde: “I found what I had not yet met with in any other publication, a number of well-authenticated cases of insane aberration of mind, narrated in a full and satisfactory manner, without a view to any system whatever” (Crichton, 1798, Vol. 1, p. V). This observation is justified by the planning of the Magazin that, adhering to a medical model rather than to the philosophical model of the time, adopted a nomothetic approach concerned with the study or discovery of general laws (Gailus, 2000, p. 75). In the Introduction to the first volume, Moritz explained: “Following a proposal by Mr. Moses Mendelssohn [a German-Jewish philosopher], I will try to apply to experimental psychology the divisions used in the medical science, and thus organize the essays in this journal under the rubrics Seelennaturkunde, Seelenkrankheitskunde, Seelenzeichenkunde, Seelendiätätik, etc.” (Moritz, 1783, p. 3). As Gailus noted, although other medical case histories were recurrent in the 18th century in line with the Hippocratic tradition, the psychological case histories reported in the Magazin were particular life histories of individuals (Gailus, 2000, pp. 72 – 73).

Moritz’s description of individual cases from a psychological perspective aroused interest in a new science of man, namely, anthropology (Linden, 1976) or, more precisely, in the study of the relationships between body and soul, medicine, and philosophy. Significantly, the physician Ernst Platner, reading psychology in anatomical terms, in 1772 wrote the following:

Finally, body and soul can be considered in their mutual relationships, limits, and connections, and this is what I call anthropology. Of course, anthropology must also have individual notions concerning the body alone and, in turn, others indicating the soul alone. But these notions must have a relationship from one or from the other side, and those which do not have it do not belong to this science. (Platner, 1772, pp. XVI–XVII)

Others, including Markus Herz, a student and friend of Mendelssohn’s, followed Platner’s ideas. Considering the rational soul as a sort of invisible organ influencing the body, Herz aspired to create a medical school in which the “teacher of soul dismemberment” would work together with the “teacher of body dissection” (Herz, 1782, pp. 87-89; 1786).

Thus, the first steps toward the epistemological dualistic perspective of the soul and the body had been made, and with it the possibility of measuring the soul, that is, an objectively measured mind, was born. Traxel rightly dated the birth of modern psychology to 1860, when Gustav Fechner’s book, Elemente der Psychophysik [Elements of Psychophysics], was published. Such a work is a clear example of making mental processes mathematical, and therefore objective, and it can be considered the starting point for the so-|5|called “new psychology” with its demarcation between the subject, the observer, and the observed object (Gundlach, 1993b).

Traxel’s observation, however, had already been made at the beginning of the 20th century by Eduard von Hartmann, who was seeking to define the profiles of “modern psychology.” Compared with the past, specifically with the 1850s, he identified the works of Fechner and Hermann Lotze as “the breaking point” (Hartmann, 1901, Vol. 13, p. 1).

But why should Fechner’s Elemente be referred to as the breaking point? What was the origin of the new mathematically based methodologies? In 1863, Wundt clarified the concept of the term “experimental” as follows: “In an experiment we produce the phenomenon artificially from the conditions we manipulate. By changing these conditions, we change the phenomenon in a measurable way.” Therefore, the decisive criterion of an experiment was measurability. Actually, “only measurement will find the constants of nature […]. Numbers are the irreplaceable means to the final purpose of an investigation for only numbers give insight into the laws of events” (Wundt, 1863, Vol. 1, pp. V–VI).

The Error as the Landmark of the Measured Mind

In September 1888, the economist Francis Y. Edgeworth read a paper before Section F of the British Association at Bath, in which he declared: “It is intelligible to speak of the mean judgment of competent critics as the true judgment; and deviations from that mean as errors” (Edgeworth, 1888, p. 602). This idea suggested that the theory of errors, at the time a part of the theory of calculus of probabilities used mainly in physics and astronomy, could also be applied to mental test scores by breaking down observed test scores into a “true score” and an “error” component. Not only was this destined to influence future psychology, it also highlighted how the “error” stemmed from the background of the mathematization process of psychology, which in turn was based on the methodological procedures of physics and astronomy. Wundt repeatedly drew attention to astronomers’ remarks on personal differences and on the related “personal equation” (Wundt, 1862a, pp. 263 – 265; 1862b, Vol. I, pp. 38 – 40, 365 – 372; 1867, p. 48). Therefore, one would be correct in deeming the concept of “personal equation” to be the origin of the “new psychology.”

A key figure in this history is the Königsberg astronomer Friedrich Wilhelm Bessel. After learning about David Kinnebrook’s 1796 dismissal from the Greenwich Observatory – and then replacing the “eye-ear method” or “Bradley’s method” with the “pointing method” – in Bessel (1822) realized |6|that “two observers need different time to convey an impression to the other.” After highlighting the importance of several factors (e.g., tiredness, reduced attention, etc.) in causing fluctuations, he concluded that a systematic error was related to individual physiological characteristics. This error famously became the absolute personal equation that concerned the real time gaps, whereas the relative personal equation referred to disagreements between astronomers.

Therefore, even though psychological factors like fatigue, short attention span, etc., were identified as the source of the error, much research looked at the possible physiological causes of the gaps and the most suitable instruments to eliminate them. It is precisely from such a detailed analysis thereof that the crucial role played by laboratories in the 19th century emerges: They became revolutionary in the system of scientific education, experimental practices, and the common work management based on the interdependence between teaching and research. As a result, they greatly encouraged scientific psychology by helping it to pursue objectivity in terms of truth-to-nature.

In the first half of the 19th century, the personal equation was actually minimized with the invention of more appropriate scientific instruments, in particular chronometers and chronoscopes. However, the physiological explanation for the personal equation was clear in Adolph Hirsch’s designation of “physiological time” (Hirsch, 1861 – 1864a, 1861 – 1864b). Hirsch explained that his experiments, conducted with optical, auditory, and electrical stimuli applied to various parts of the body, were carried out by having recourse to an instrument (the chronoscope) that can be regarded as the link between astronomy and psychology. Given its major role in experimental research, it became one of the instruments deemed essential in psychology laboratories (Gundlach, 1996, p. 65).

The invention of the chronoscope took place in the military sphere. In 1843, Louis-François-Clément Breguet, in collaboration with an officer of the imperial Russian guard, von Konstantinoff, undertook work for the Russian government on the design of an instrument that, using electricity in accordance with the instructions provided by C.-S.-M. Pouillet (1837), would measure the exact velocity of a bullet at different points of its trajectory (Breguet, 1845) (see Figure 1.1).

Completed the following year and named the “electro-magnetic chronoscope,” Charles Wheatstone contested the paternity of the instrument, claiming to have already invented it in 1840 (Wheatstone, 1845). He drew inspiration from the construction principle of his own electromagnetic telegraph, recounting that, during a meeting with Konstantinoff in London in January 1842, the latter had showed such interest in the instrument that he persuaded Wheatstone to send it in January 1843 to Paris, where the Rus|7|sian officer was then living. The only condition stipulated by Wheatstone was that no description be provided before his publication. After stressing that Breguet’s chronoscope was “much less precise, much more complicated and expensive” than his own previous models, he described the construction plan of his chronoscope, which allowed for the reading of time intervals of 1/100 of a second (Wheatstone, 1845, pp. 1557 – 1560).

Figure 1.1   Breguet’s Electro-magnetic chronoscope (Bub, 1863, p. 550).

Improved in 1847 by the Swiss clockmaker Matthäus Hipp, the instrument presented problems concerning the functioning of the electromagnetic parts meant for connecting and separating the hands. To resolve these problems, Hipp constructed an instrument with a steel ball that touched two electric contacts, thus enabling a constant time during which the chronoscope could be regularly calibrated (Oehlschläger, 1848, 1849). Known as “Hipp’s Free-Fall Instrument,” it was subsequently replaced by other calibration systems, such as the chronographic method or the control hammer.

In other words, instruments, like today’s surveys, served to categorize human experience, i.e., to classify mental events together in homogeneous sets.

How to Measure the Mind: The Objectification of Mental Processes

Hipp’s chronoscope, originally constructed for military purposes, was judged “immensely useful to both the physicist and the physiologist” (Hirsch, 1865, p. 187). Hipp made the chronoscope available to Hirsch, who was his experimental subject. It was used “to subject the different functions of the brain and the nervous system to physical rules” (Hirsch, 1865, p. 185), particularly to the senses of sight, hearing, and feeling [Gefühl], considered in physiological terms (see Figure 1.2). Indeed, Hirsch introduced the term “physiological time,” later replaced with “reaction time,” to refer to the time that elapsed between the presentation of a stimulus and the subject’s reaction to it, that is, the time needed for its reception and conduction to the brain, volitional transmission to motor nerves, conduction in these nerves, and the subsequent contraction of the muscle. Findings obtained by Hirsch using |8|statistics showed how the “physiological time” varied depending on the sensory organ being stimulated, on whether the observers were alert or tired, and on whether the stimulus was expected or unexpected.

Figure 1.2   The design of Hirsch’s chronoscope experiments (Hirsch, 1865, table).

This interest in the measurability of the conduction speed in nerves had divided the exponents of the physiological school of Berlin into the so-called vitalists, headed by the physiologist Johannes Müller, and his materialistic students Carl Ludwig, Émil Du Bois-Reymond, Hermann von Helmholtz, and Ernst von Brücke. Maintaining that, counter to Müller’s idea (Müller, 1834–1840), nerve impulse transmission could indeed be measured, they thought that living beings were subject to the same laws applied to the rest of nature and wondered whether psychic activity could correspond to a variation detectable on a material basis (e.g., Helmholtz, 1850a, b). In addition, physiologists like Carl Vogt propagated a radical materialism by affirming that “all those capacities that we consider to be activities of the soul are merely functions of brain substance” (Vogt, 1847, p. 206). However, although Du Bois-Reymond (1848) was the first to deal with chronometry, Helmholtz was the first to put it into practice: Between 1850 and 1852 (Helmholtz, 1850a, 1850b, 1850c, 1851, 1852), he experimented on the principles of chronometry following two methods: “Pouillet’s method” and “Young’s graphic method.”

From 1837 onward, the French physicist Claude-Servais-Matthias Pouillet had devoted himself to measuring the strength of the electric current. To that end, he devised a galvanometer, whose invention dated back to the previous decade (Pouillet, 1837). The two typologies, which maintained the same principles, were defined as “the tangent compass” and the “sine compass” (the latter invented by August de la Rive). In 1844, Pouillet announced that he had used the galvanometer to determine both the time elapsing between the lighting of a cannon and the expulsion of the ball from its mouth, and the speed of a shell at different points of its trajectory. The method con|9|sisted of placing a system of silk threads followed by a system of wires so that the shell established the electrical connection by deflecting the silk thread and suppressed it by deflecting the wire. The time of the shell’s passage could be inferred by the deflection of the galvanometer’s needle.

In 1850, Helmholtz modified the instrument by applying two parallel coils at a distance equal to their radius, so that the needle moved in a uniform magnetic field. This galvanometer was applied using Pouillet’s method (Figure 1.3). In the preparation of the frog’s gastrocnemius muscle, the nerve was stimulated at various distances, making it possible to measure the time elapsing between the stimulation (electrical irritation) of a motor nerve and the muscular contraction, revealing that stimulation and perception were not simultaneous. With Pouillet’s method, there was power in the galvanometer during stimulation, whereas there was no power when the muscle contracted. On the other hand, with the graphic method, a writing nib left a trace of the time elapsed between stimulation and contraction on paper wrapped around a rotating cylinder (i.e., the kymograph invented by Carl Ludwig; see Figure 1.4).

Figure 1.3   Design of Helmholtz’s galvanometer (Kuhn, 1866, p. 1193).

The data Helmholtz obtained with the two methods were similar enough (26.4 ms with the first method, 27.25 ms with the second; somewhere between 50 and 100 feet per second for human sensory nerves) and were confirmed by later physiologists such as Nicolas Baxt (1871), Rudolph Schelske (1864), and Karl Vierordt (1868). In particular, the experiments on humans were carried out together with one of his collaborators, the Russian Nicolas Baxt (Helmholtz, 1870, 1871; Helmholtz & Baxt, 1867), and continued with the aim of establishing the time necessary for developing a conscious experience. For this purpose, the phenomenon of after-images was employed because it enabled verification of the time-course of the conscious recognition of a stimulus after its cessation. The experiments involved the use of |10|rotating disks with open slots showing a bright visual stimulus of very short duration, followed by the appearance of an image on the retina, which persisted for a very short time after the removal of the original image. Baxt (1871) refined the experimental procedure by considering the time needed for the extinction stimulus to become conscious. He also demonstrated a relationship between the recognition time and the size and complexity of the stimulus, that is, the number of recognizable objects it contained.

Figure 1.4   Kymograph for register changes within the arterial pressure and respiration simultaneously (Ludwig, 1856, Figure 41, p. 85).

Helmholtz followed the same procedure in his investigations into attention and showed that attention may be directed toward a point in visual space different from the fixation point of the gaze. Indeed, he was the first researcher to empirically provide insightful observations on covered or hidden spatial attention, in the sense of the ability to pay attention to some part of the periphery of vision even without shifting one’s gaze, i.e., without fixating it, unlike attention that involves head or eye movements. To prove these phenomena, Helmholtz used a wooden box with two pinholes: Looking into it through the pinholes, he would attend to a particular region of his visual field without moving his eyes in that direction. When a spark was lit to briefly illuminate the box, he got an impression of only the objects in the region he had been attending to, thus showing that attention could be deployed independently of eye position and accommodation. As he observed: “[…] it seems to me that by a voluntary kind of intention, even without eye movements, and without changes of accommodation, one can concentrate |11|attention on the sensation from a particular part of our peripheral nervous system and at the same time exclude attention from all other parts” (Helmholtz, 1894, p. 95).

Helmholtz’s exploration of attention became a cornerstone of the research on time carried out by Donders and strictly related to it as well as on the Wundtian and Jamesian perspectives. The prelude was Hirsch’s above-mentioned chronoscopic research on the speed of transmission in sensory nerves. Moving from the astronomical to the physiological context and approaching consideration of the psychic, Karl Vierordt defined physiological times as Zeitsinn [a sense of time] (Vierordt, 1868). But the decisive step was taken by Sigmund Exner, a physiologist in Vienna who had studied in Heidelberg under Helmholtz and Wundt’s uncle, Friedrich Arnold. To replace the expression “physiological times,” he coined the term “reaction times,” by which he meant “the time needed to react consciously to a sensory impression”: that is, how much time was consumed in the central processes (Exner, 1873, p. 609). To investigate this time – divided into seven steps and measured in various individuals, sense organs, skin areas, and circumstances – Exner developed the Neuramöbimeter, an instrument built by the Viennese mechanic Heinitz, which consisted of a telegraphic key and a tuning fork.

Even though the Exnerian model took account of the influence of factors such as attention, age, alcohol, etc., the emphasis remained on physiology. The physiologist Franciscus Cornelis Donders had done better a few years before.

In a portrait painted by his second wife just before his death in 1888 – 1889, Donders can be seen sitting at his desk with Helmholtz’s bust in the background (Figure 1.5) to demonstrate his affinity with Helmholtz’s lines of research, from energy conservation to reaction times and vision.

Indeed, Helmholtz was one of the first physiologists to introduce a sort of cognitive mechanism into physiology, thus inspiring radical new directions in the investigations he conceived at an empirical level. Starting from Section 26 of his 1867 Handbuch der physiologischen Optik [Handbook of Physiological Optics], he assumed that spatial perception was produced by unconscious and unnoticed inferences or judgments via associative processes; in other words, by comparing the inferences of perception to syllogisms in which the premise was set up inductively. The process was based on the premise that the stimulation of any retinal nerve fibre initially yielded a sensation varying in hue, intensity, and local sign (Localzeichen), whose origins date back to Hermann Lotze’s attempt to combine various theories on spatial perception, from the innate to the empirical.

Indeed, by assuming a synchronization between mental events and the events of the material realm – as if they could interact although they did not |12|(Lotze, 1852) – Lotze introduced the concept of the “local sign,” which elucidated the relationship between mind and matter in terms of space and movement perception. In this perspective, psychological space was made up of sensations that in isolation were not spatial, but whose stimulation matched the shifting of the stimulus from one point in physical space to another. Thus, the local sign was intended as an inherent qualitative factor, through which a visual or tactual sensation was distinguished from others thanks to its position in space. Moving away from purely mechanical philosophical assumptions, Lotze consequently conceived space perception as an activity of the construction of external objects and events in consciousness (Lotze, 1856), paving the way for the Helmholtzian approach to the issue.

Figure 1.5