eysenck's dimensions of personality

J. M. Williams Dimensions of Personality 1

The Hypothetico-Deductive Method,Operationism, and Eysenck's Dimensions of

Personality:Preparations for a Science of Human Personality

By John Michael Williams

[email protected]

2015-09-26

An essay on the logic of the hypothetico-deductive method and onoperationism, leading into Eysenck's trait/type personality theory

Copyright © 2015, John Michael Williams.All Rights Reserved


Prefatory Note

This article originally was written in 1969. Most of the references cited are limited to that period, but some of the text has been updated according to events up to the present.

The Preliminaries section of this article totals more than half of the text. None of the details in that section is essential to the Eysenck-specific material; but, hypothetico-deductive method, operationism, and dimension must be concepts familiar to the reader for a good understanding of Eysenck's work in its context.

I wrote the Preliminaries section partly for my own benefit -- but I also wrote it in hopes that that section would give the reader a good idea of what Eysenck's context, and the context of much of modern psychology, really was.


Table of ContentsPrefatory Note............................................................................................................................2Introduction...............................................................................................................................4Preliminaries..............................................................................................................................5

• The Hypothetico-deductive Method..................................................................................5• Operationism......................................................................................................................9

• As Defined......................................................................................................................9• As Applied By Eysenck..................................................................................................9

• Dimension.........................................................................................................................11• One-dimensional Spaces.............................................................................................11• Two-dimensional Spaces.............................................................................................12• Three-dimensional Space............................................................................................17• Four-dimensional and Higher Spaces........................................................................17• Independence of Axes..................................................................................................18• Reduction of Dimensions.............................................................................................20

Eysenck's Approach to Personality........................................................................................23• General Program..............................................................................................................23

• Personality...................................................................................................................23• Personality Research...................................................................................................23• The Hierarchical Organization of Personality...........................................................24• Contrast with a Less Experimental View..................................................................25

• Dimensions of Personality...............................................................................................26• The Freudian Dimension............................................................................................26• The Orthodox Psychiatric Dimension (ca. 1969).......................................................26• Eysenck's Dimensions.................................................................................................27

• Criterion Analysis............................................................................................................29• Background..................................................................................................................29• Method..........................................................................................................................29

Summary..................................................................................................................................32Conclusion................................................................................................................................33References................................................................................................................................34


Introduction

Hans Jurgen Eysenck was born in Berlin in 1916 and received his early education in Germany. He left Germany in 1934, moved to England, and was granted his Ph. D. degree by the University of London in 1940. During 1942 - 1947, Eysenck was a research psychologist at Millhill Emergency Hospital, where he came in contact with hundreds of war-disabled soldiers. He spent a few years in the United States during 1949 - 1954 but returned to England in 1954, where he generally remained until his death in 1997. Further biographical details may be found in Wikipedia (en.wikipedia.org/wiki/Hans_Eysenck), Hall and Lindzey (1957, pp. 382-383), and in Debus (1968).

Eysenck is considered a trait/type personality theorist primarily on the basis of his work during the 1940's and early 1950's. Eysenck himself said he was strongly influenced by the type theories of Jorden, Gross, Jung, Kretschmer, and others (e. g., Eysenck, 1953, chapter 1). Eysenck's own, unique approach in the trait/type field has been called an "attempted synthesis of the procedural sophistication of the psychometritian with the insight of the clinician" (Hall and Lindzey, 1957, pp. 381 - 382).

In his later work, Eysenck has made use of the learning theories of Pavlov and Hull (Hall and Lindzey, 1957, p. 388), and others, and he has been a leader in developing from these theories what is now called behavior therapy. Eysenck was a prolific and opinionated writer; some of his later views on genetics of IQ led his critics to view him as biased toward "right-wing" beliefs.

The present paper will deal almost exclusively with Eysenck's trait/type approach to personality. Further information on behavior therapy can be found in Wikipedia (en.wikipedia.org/wiki/Behaviour_therapy; .../wiki/Cognitive_behavioral_therapy), in Eysenck (1959), and in articles republished in Millon (1967).

Hall and Lindzey (1957, chapter 10) class Eysenck with the "factor theorists". Eysenck, however, does not follow the same route as those factor analysts he has called "the mole-like calculators of innumerable correlations between measures taken without any theory or hypothesis capable of proof or disproof . . . who seek to atone for the scientific barrenness of their results by stressing the mathematical beauty and purity of the methods used, and who seem incapable of seeing the wood for the trees" (Eysenck, 1952, p. 16).

Eysenck's approach is modelled after that of the physical sciences -- after that of physics, chemistry, and much of biology. Behind Eysenck's concepturization of the problem of personality lies what might be called the "physical science metaphor" (cf. Embler, 1966, pp. i-ix), and it is this metaphor -- the metaphor of operationism and of the hypothetico-deductive method -- which has led Eysenck through his trait/type theory into


the theory and the technique of behavior therapy.

In what follows, I try to suggest what it is that I mean by the "physical science metaphor" and how Eysenck's trait/type theory is organized around this metaphor as a central conceptual core. Readers who know they are already familiar with the terms I have mentioned above -- "hypothetico-deductive method", "operationism", "dimension" -- are asked to be patient. Bear with me and read what follows anyway, because my point is very important, although the details often are not.

Readers who don't understand these terms, but who are impatient with them nevertheless, I ask to read on: In a sense, there are many doors, and many rooms, and notwo are the same; but, the key to knowledge, whatever it may open, requires many turns. Impatience merely is just one of many paths to a passive, faultless life -- a life spent limply, a life of weakly peeping through a narrow keyhole. In that room there may be pretty colors, pretty shapes and sounds. But, soon they pass, the colors fade, the shapes blur, and all that world loses its meaning. The scene goes lost before a fixed and staring eye. One is deaf, who heeds only ones own voice . . ..

Preliminaries

The Hypothetico-deductive Method

This method is the idealization of a process by which Western physical scientists have converged upon solutions to various physical problems over the past four hundred years or so.

First, the hypothetico-deductive method consists of guessing an explanation for some phenomenon. The guess is called an hypothesis. Let us look at an example:

For example, one phenomenon to be explained is that

hydrogen gas forms water when it is burned in air. (p)

The water referred to in phenomenon (p) might appear as tiny droplets condensed on the walls of a closed glass jar in which a hydrogen flame was burning. One guess to explain this phenomenal appearance of water might be that

water is made up of hydrogen and air, (h)

and that burning unites the hydrogen and air to form water. This guess, labelled "h" in the right margin, is the first hypothesis which we have made in this example to explain "p" above.

The second part of the hypothetico-deductive method is the deductive part: In this method, after an hypothesis (guess) has been made up, the scientist forms a deduction by making some testable statement based on the hypothesis.

For example, one deduction from hypothesis (h) above might be that, because water is


hydrogen plus air,

one should be able to use up all the air in a sealed bottle simply by (d1)burning enough hydrogen in it.

In other words, deduction (d1) says that we should be able to change all the air in the bottle into water, provided we burn enough hydrogen in it.

It should be noted that deduction (d1) follows logically from hypothesis (h) regardless of what the real facts of nature might be; that is, if (h) is true, then (d1) will be true simply by logical reasoning.

The third part of the hypothetico-deductive method is very closely associated with the second (deductive) part and consists of the testing of the deduction by means of an experiment. If the deduction is contradicted by the results of an experiment designed totest it, then the deduction must be concluded to be false (or the experimental procedure tobe faulty).

By the laws of logic, no false statement can be deduced from a true hypothesis; therefore, if the deduction is proven false-to-facts, then the hypothesis from which it was deduced also must be false-to-facts. On the other hand, if the deduction should be validated by favorable experimental results, the hypothesis still might be false. For example, suppose we deduced from (h) above that, therefore, water must be more dense than hydrogen or air (because it contains both). Now, in fact, water is more dense thanhydrogen or air, or hydrogen plus air, and this deduction easily can be proven true by simple measurements; however, (h) is false, as is obvious from common knowledge or the next discussion below.

In general, experimental evidence only can prove an hypothesis false; an experiment never can prove an hypothesis true.

Returning to the example above, here is a possible experiment to use in order to test the deduction (d1): What we might do is to take a bottle of air and pipe hydrogen gas intoit by means of a small tube. Then, we might light the gas and wait for the air to be consumed. It is worth mentioning that the details of an actual apparatus for this experiment might well be similar to those of Lavoisier's famous experiments on the calcination of mercury, experiments which led to his discovery of oxygen in the late 18th century (e. g., Sneed and Maynard, 1944, p. 8). If we performed this experiment, we would be surprised to find that

the hydrogen flame dimmed and went out after only about one-fifth (e1)of the air in the bottle was consumed.

As a result, we would see, as in the phenomenon (p) above, that some water was produced by the burning hydrogen; the experimental result (e1), however, would show that our deduction (d1) above was false and therefore that the hypothesis (h) also was false. In summary, our conclusion would be that the experimental result (e1) had shown that it is not true that water is made up of hydrogen and air.

The test of hypothesis (h) above should not be considered a waste of time, however.


True, we would have failed to explain the phenomenon (p), which explanation was our original purpose in applying the hypothetico-deductive method; but, we would have succeeded in increasing our knowledge of the physical world. Our application of that method as in the example above enabled us to discover a new phenomenon p', namely that

only one-fifth of the air in a bottle can be consumed by burning (p')hydrogen in it.

As stated, the new phenomenon (p') is nearly identical to the experimental result (e1) above. The important difference between (p') and (e1) is that (p') is more general. In stating (p'), we tacitly have assumed that the experimental result (e1) is a stable, repeatable result. This tacit assumption constitutes what is called the induction of a general "fact" from a specific result. It should be recalled, now, that the original phenomenon (p) also was stated initially as a general, induced fact. Thus, as a result of a single application of the hypothetico-deductive method to a single phenomenon (p), we now have two phenomena, (p) and (p'), representing physical findings both of which eventually can be put to use in subsequent contexts.

Let us expand upon our findings to see how our new knowledge might be used. Aside from industrial applications, one use for the new experimental phenomenon (p') would be in future research in the area of science -- namely, chemistry -- in which both (p) and (p') arise. Phenomenon (p') could be used by a chemist to help converge on the "truth", as it were, which must underly the stability of the physical phenomena with which that chemist is familiar. For example, suppose a certain chemist was familiar with hypothesis (h) above ("water is made up of hydrogen and air"), but that this chemist knewperfectly well that the experiment had been performed and that therefore hypothesis (h) was false. The question then arises, What is water, then?

Knowing the falsity of (h), then, it would not be hard to deduce that

water consists of hydrogen and an unknown gas which is found (d2)in air.

Proceeding thus, the chemist then might test the deduction (d2) by trying to unmix or dissociate the presumed components of water, perhaps by boiling it. Boiling would fail, of course, because by boiling water the only new product would be steam -- which always would condense back the the same water which initially was boiled. Boiling the water would prove nothing.

Now suppose our chemist tried to dissociate water not by boiling but by the process of electrolysis. In electrolysis, two electrodes would be used to pass a (direct) current through the water. Upon electrolysing some water, our chemist would have found experimentally that

two different gasses, X and Y, were created at the two differentelectrodes, and one of those gasses, Y, say, was indistinguishable in (e2) all its properties from hydrogen gas.


Also, in a subsequent experiment, the chemist would find that

when hydrogen was mixed with enough of the new gas X and burned, (e3)all of the X would be consumed.

Using a little induction, by generalizing the experimental results (e2) and (e3) to the status of experimentally established facts, our chemist then would conclude that

the gas X is not air. (p'')

Here, in a very simple application, is a use for the phenomenon (p') in research which I mentioned above: It was (p') that enabled the chemist to conclude that the gas X was not air. The chemist's reasoning here was very simple: (p') states that if air is used to burn hydrogen, about one-fifth of the air will be consumed. But, when the gas X is used to burn hydrogen, all of the X is consumed; it thus follows that X can not be air.

We therefore have arrived at three physical phenomena, or facts, (p), (p'), and (p''), all of which are tied together because they arose from one another via the hypothetico-deductive method. In addition, the experimental results (e2) and (e3) also became general, known phenomena in the course of ariving at (p''). In actual practice, of course, all the above experiments would be repeated several times, under varying conditions, so that it was assured that the results actually were stable phenomena and not just lucky accidents. If the results turned out to be somewhat unstable -- that is, not always repeatable even with strict experimental controls -- then statistical inference, as often used in the social sciences, might be applied to help support the conclusion that the experimental results (e1) - (e3) truly did represent stable underlying phenomena. In general research practice, it is the manifest stability and repeatability of the results of physical experimentation that ensures that virtually every new application of the hypothetico-deductive method to physical phenomena will increase the breadth and precision of our physical knowledge.

To expand a little more on the points just made, let us carry the water discussion a little further. Suppose that in order to explain phenomena (p) and (p') above, we cleverlyguessed that

air is a mixture of different gasses, (h')

and that it is just one of the components of air (namely oxygen), not air itself, which unites with hydrogen to form water. We thus have a new hypothesis (h'). In addition, let us formulate still another hypotheses, namely that

one-fifth of air consists of the gas X mentioned above. (h'')

Deductions then could be drawn from these latter hypotheses, and these deductions in turn could be tested by experimentation. The resulting experiments would suggest new physical experimental phenomena which in turn could be explained by means of new hypotheses. Ideally, it is the stability of physical phenomena plus humankind's endless creative ability to guess new hypotheses about these phenomena -- the ability to organize and use what is known -- which has enabled the human race to reach its present state of mastery over a very large portion of the physical world.


Other discussions of the hypothetico-deductive method can be found in Wikipedia (en.wikipedia.org/wiki/Hypothetico-deductive_model), in Russell (1948), Russell (1954, pp. 194 - 196), Walker (1963, p. 25), Kerlinger (1964, pp. 13 - 17), or Boring (1950, pp. 13 -14).

Operationism

As Defined

According to the doctrine of operationism, any concept is synonymous with a set of operations corresponding to it (Bridgman, 1927, p. 5). If no set of operations can be found that corresponds to a given concept, then a strict operationist is forced to conclude that any statement about the concept in question is meaningless. Such strict operationists are not known to exist.

The operations corresponding to a concept may be physical, as in the case of the concept of length, which corresponds to the operation of measuring a distance along some object with a ruler or some similar instrument. The operations alternatively may be mental, as in the case of the concept of addition, which may be understood as corresponding to the mental operation of applying the rules of addition as we all have learned them as school children. The mathematical concept of continuity also corresponds to a set of mental operations (see Bridgman, 1927, p. 5).

A few more imaginative examples might be in order: The operational concept of intelligence is synonymous with the operation of scoring a certain mark on an IQ test. Operational statements about "good students" might be about students with a certain grade-point average, or some such operational thing. Statements about "communists" would imply a set of operations by which it can be determined whether a given person is a communist or not -- or else such statements would be operationally meaningless. Statements about human love often are operationally meaningless; however, for simpler forms of life, love is easily defined operationally: In male crickets, for example, love can be defined easily and clearly as their act of chirping -- however, because female crickets do not chirp, it appears that love, for them, is not defined and therefore must be meaningless. Not quite cricket; so, further research obviously is indicated in this area.

As Applied By Eysenck

As the references cited above might suggest, the best primary source on operationism is Bridgman. P. W. Bridgman (1882 - 1961) won the Nobel prize in 1946 for his investigations of new phenomena in high-pressure physics. Bridgman is considered the founder of operationism as a general experimental discipline. He extended his ideas intothe realm of social science; he wrote, for example, "Wherever we temporize or compromisein applying our theories of conduct to practical life we may suspect a failure of operational thinking" (Bridgman, 1927, p. 32).

But, this sort of temporizing and compromizing in applying theories sounds all too


familiar: Personality theories [in the 1960's] are theories rarely applied during actual therapy; and, when they are applied, it usually is on an ad hoc basis, in the form of that indefinite sort of theoretical mish-mash called the "eclectic" approach. Therapists do therapy; personality theorists, as such, do not. Personality theorists of the 1960's could not bear any but the most naive operational tests; their theories cannot be made consistently operational without a great deal of temporizing and compromising. And it isjust here that Eysenck jumps off operationism and onto the psychotherapists.

Psychotherapists, Eysenck might say, fail to put their money where their mouths are. They won't put their theories (or their practices) to crucial, public, quantitative, empiricaltests. In the Eysenck polemic, instead, many therapists make the patient put up the money for the privilege of being treated. Thus well financed, our Eysenckian therapist then proceeds to run off his or her own mouth at random, in the professional journals, preaching about the theoretical beauty, the literary-artistic implications, and/or the personal meaningfulness of his or hers approach. On "meaningful" organismic approaches, see, e. g., Eysenck, 1952, pp. 276 - 278.

The therapist's theoretical approach as such, of course, has no operational meaning; the reason is that, during therapy, the therapist never actually carries out the sequence of operations which a consistent, non-tautologous interpretation of the theory would say should be performed. In fact, it was not until the last few years of the 1960's that Eysenck and others (e. g., see Berelson and Steiner, 1964, pp. 287 - 291; Eysenck, 1952, pp. 28 - 32; Eysenck, 1959) discovered that psychotherapists, eclectic or not, uniformly failed to produce any convincing evidence that recovery rates for neurotics under therapy were any better than recovery rates for neurotics under treatment by ordinary general practitioners -- or, one might guess, under treatment by their local preachers or bartenders, as the case might be.

From the writings above, instead, one would have to conclude that many psychotherapists temporize and compromise. They carefully select which patients they even will attempt to treat. They shut their empirical failures out of their non-operational minds by prolonging treatment for indefinite periods; by referring the patientto new therapists with other theories; by drugging up the patient so he or she doesn't do anything nutty; by clapping the patient into an institution for the "out-of-mind, out-of-sight"; or, by diagnosing the patient as a "character disorder", or something similar, so the patient can be considered a hopeless case anyhow. These are the actual, practical techniques of a non-operational theorist-therapist as I believe Eysenck might describe them.

On the other hand, as a trait/type theorist, Eysenck's own program for solving (or declaring meaningless) all the problems of personality includes the following steps: (a) togather a great deal of descriptive, objective, empirical data on the phenomena of personality; (b) to correlate and factor-analyze these data in order to define what Eysenckcalls the dimensions of personality; and, (c) to converge hypothetico-deductively on an accurate, scientific theory of personality by repeating experimental application of steps (a) and (b).


Eysenck thus plans to attack the problems of personality theory as though they were problems in physical theory. Physical science does work, reasons Eysenck; and, ideally itworks because of the hypothetico-deductive method (but, cf. Skinner, 1956; Hilgard and Bower, 1966, pp. 142 - 143). Therefore, why not use the same method to move away fromuseless therapies and into the development of a workable science of personality?

A "science of personality": For Eysenck, this is what I mean when I label it a physical science metaphor.

Dimension

Dimensions are directions of measurement. For example, the dimensions of a shoe box might measure 12 inches by 8 inches by 6 inches; more briefly, one might write these dimensions as 12 x 8 x 6 inches. The numbers given would measure the box in the directions length x width x height. Likewise, the dimensions of a school classroom mightmeasure 25 ft, 30 ft, and 9 ft. The Playmate of the Month might measure 36, 22, and 36 inches around certain perimeters. All the numbers just given are measures of various dimensions.

In many mathematical and physical-science problems, it is very important to find out how many dimensions are needed to locate a point. In other words, equivalently, it is important to know how many numbers are needed to locate, or to specify the location of, agiven point.

One-dimensional Spaces

For example, if we would like to specify the location of a given point P on a certain line,then we would have to specify only one number. In Figure 1 below, it can be seen that any point P on the line can be located by giving a single number p, where p is the positiveor negative number measuring the distance of P from the zero-point, or origin of measurement O, of that line.

Figure 1. A one-dimensional space.

The single number p (or p') needed to locate a point P on the line is called the coordinate of P.

p' p- +

O

p' (negative) p (positive)


Because any point on the line in Figure 1 can be located by means of just one number (or coordinate) measuring that point's distance from the origin of measurement O, the line is called one-dimensional. In general, all isolated lines are called one-dimensional spaces because, given an origin, one and only one number is needed to locate any point on such a line. There is no "space" on an isolated line for any point to escape being located by means of a single number.

Two-dimensional Spaces

Now let us look at the plane illustrated below in Figure 2. The three points, P, Q, andR which are drawn in Figure 2 do not lie on a single line.

Figure 2. Three points on a plane.

To emphasize this observation, a line through points P and Q has been drawn in Figure 3 below; it easily can be seen that point R does not lie on that line.

O

P

Q

R


Figure 3. A line drawn through points P and Q.

If the reader will bear with another statement of the obvious, it likewise can be seen from Figure 4 below that the point P does not lie on the one line that can be drawn through points Q and R.

Figure 4. A line drawn through points Q and R.

O

P

Q

R

O

P

Q

R


The importance of these seemingly trivial observations is that the locations of the three points P, Q, and R of Figure 2 cannot be specified by giving a single number for those locations; they are not on one line.

To become a little more specific, if a line L is drawn through points P and Q as in Figure 3, and if an origin of measurement O' is assigned to that line, then the locations both of P and Q can be specified exactly by means of two single numbers, call them p andq, which give the respective distances of those points from O' along L; this is shown in Figure 5:

Figure 5. Locating the point P by the number p andthe point Q by the number q, using the line L.

In Figure 5, however, the closest we can come to locating the point R on the line L is todraw a new line L' perpendicular or orthagonal to L. In Figure 6 below, the new line L'is shown crossing the line L at the point S.

O

P

Q

R

p q LO'


Figure 6. A try at using the line L to locate the off-linepoint R. The number s gives the location of the point S

along L. L' shows the error in using L to locate R.

After this, we may claim (falsely) that the point R is located on the line L, and that thelocation of R is just the distance s of the point S from the local origin O'. If L and L' are at right angles, as shown, then the distance from R to S shows the minimum possible error in the assumption that P, Q, and R are in line.

In Figure 6, claiming that the point R is located on the line L -- that the location of R is the same as the location of S -- does enable us to use just one dimension, the line L, to locate all three of the points P, Q, and R. However, such a claim introduces an error in the location of R. One might imagine this error as analogous to an error by a therapist in evaluating the condition of a patient.

Be that as it may, if we did claim that point R was located at point S, then the amount of the error in location could be described as the distance between the two points R and S along the line L'. Looking at Figure 6, we can see that this error eould be quite large. How would a therapist express the measure of an error in patient evaluation? A difficultquestion -- much harder than one involved the location of R in Figure 6 . . ..

Returning to the geometry, Figure 7 below illustrates how the points P, Q, and R would look if we assumed, as above, that all three of them lay on the single line L. This figure obviously is a distortion of the truth, as can be seen very obviously by compating it to Figure 2 above. Such a distortion always will occur when we attempt to apply a one-dimensional solution to a two-dimensional problem:

O

P

Q

R

LO's

S

L'

error


Figure 7. The locations of P, Q, and R if it is assumedthat R lies on a line with P and Q.

Lets get a little more two-dimensional: If we allow ourselves two independent numbers to locate a point in a plane, then any such point can be located with no error. In Figure 2 above, if the two orthogonal axes in which it is drawn are labelled x and y; and, if the origin of these axes is located at point O; then, the three points P, Q, and R may be located entirely correctly -- errorlessly -- by using these three pairs of numbers: (px, py), (qx, qy), and (rx, ry). Using just the point Q as an example, Figure 8 below showshow to locate that point by means of the two numbers qx and qy.

Figure 8. Locating the point Q in the plane by means of a pairof numbers (qx, qy).

O

P

QR

O

P

Q

R

Qx

Qy

qy

qx

y

x

(qx, q

y)


In Figure 8, qx measures the orthogonal distance of the point Q from the point Qy on the x-axis; the number qy measures the orthagonal distance of the point Q from the point Qx on the y-axis. The points Qx and Qy are somewhat analogous to the point S in Figure 6 above.

In Figure 8, then, the numbers qx and qy in a sense measure the total "error" in location of the point Q with respect to the origin of measurement O. Of course, this "error" is just an intentional offset, a simple connection, when viewed in two dimensions. In Figure 6, no such error measurement strictly was available, because all measurementswere required to be carried out along the one line (dimension) L. In Figure 8, once the two numbers qx and qy are given, no error is left over, and the point Q will have been located in the plane with perfect accuracy.

There are other ways than Figure 8 for finding two numbers which locate any point in a plane; but, always, no fewer than two such numbers will be required. Using only one number always results in an error. Each of the two numbers needed to locate a point in a plane corresponds to a value on a different dimension sweeping over the plane; so, therefore, such planes are called two-dimensional spaces.

Three-dimensional Space

Just as any plane can be shown to be a two-dimensional space, the space which we move around in in everyday life can be shown easily to be a three-dimensional space. The obviousness here is evidence enough that a(nother) long-winded geometrical discussion is not necessary. Let it be enough to say that any point in a three-dimensional space can be located by the use of three numbers -- x, y, and z, say -- each number measuring the axial distance of that point from some fixed, well-defined origin. The three numbers might correspond, for example, the latitude above or below the equator, the longitude, and the altitude above or below sea level.

Three orthogonal axes conventionally are used to locate points in a three-dimensionalspace. The locations of such points are written conventionally as "(x, y, z)", in which, for some point p, the values of x, y, and z would correspond to distances px, py, and pz along the x, y, and z axes, respectively.

Four-dimensional and Higher Spaces

Four, and five or more dimensional spaces are used in mathematics and in the physicalsciences, but intuition fails if we try to imagine how the coordinates in, say, a five-dimensional space, give the physical, spatial "location" of such a point. However, if dimensional measurements are considered just to be numbers merely specifying or describing an object, not locating it in physical space, then it is perfectly reasonable to speak of five-dimensional, or greater, objects.

For example, a piece of wire may be specified by its length and diameter dimensional


"coordinates" thus: (length, diameter) = (100 meters, .09 centimeters). Such a wire, as described, would be two-dimensional. But let us suppose that we knew that the wire hada hardness of 6 on a certain hardness scale, an electrical conductivity of 0.8 relative to copper, and a reflectivity averaging 0.5 in the visible spectrum. The wire then could be described as having five dimensions and could be viewed as located in some five-dimensional space by its coordinates, (100, .09, 6, .8, .5).

As another example, suppose that a certain automobile was measured in three dimensions to be (length, width, height) = (17, 7, 6), all in feet. We easily could add a weight of 2,000 kg and number of seats five to that measure, making it five-dimensional. Our automobile then might be plotted as a point in a five-dimensional "space" for which the axes would be labelled "length", "width", "height", "weight", and "seats" in the proper units of measurement. The coordinate location of the automobile then could be written as (17, 7, 6, 2,000, 5).

Let us further suppose that the owner of this automobile had a measured Wechsler-Bellvue IQ of 153, and a recent GRE Aptitude Test score of 217 verbal and 780 quantitative. With this, our automobile would become eight-dimensional with coordinates (length, width, height, weight, seats, IQ, GRE verbal, GRE quantitative) = (17, 7, 6, 2,000, 5, 153, 217, 780). For readers not acquainted with the United States GRE ("Graduate Record Examinations"), which dates from the 1950's, it is a set of standard tests for predicting success in entry-level topics required by institutions of higher learning, such as colleges.

Finally, it might happen that our automobile owner can run the mile in four minutes, ranked number five in the world in a recent postal chess championship tournament, reads text at a rate of 30 words per minute, and spends an average of 2.5 hours a day trying to make a sandwich each evening for dinner. Our automobile's dimensions then could be written to total twelve, and its coordinates would be, (17, 7, 6, 2,000, 5, 153, 217, 780, 4, 5, 30, 2.5).

Our automobile owner begins to fill out as a somewhat unusual person now, and perhaps we get a hint of what Eysenck might have had in mind when he referred to the "dimensions of personality".

Independence of Axes

The coordinate axes by which a point is located in some n-dimensional space either are independent or not. If the axes are independent, then it is possible to change the position of the point arbitrarily by changing the value of any one coordinate without changing the value of any other coordinate. When the axes represent the physical position of a point, those axes usually are independent: It always is possible to move something up and down in space without moving it either left or right or towards or away; it always is possible to move something away without moving it up or down; etc.

However, in many cases, some or all of the axes locating a point may be mutually dependent, especially when more than simple physical position is being expressed.


For example, consider the wire mentioned above. Given a two-dimensional wire (length, diameter), if the wire were stretched by pulling on it to make it longer, then its diameter would change; at least part of the wire would get thinner. Therefore, for a given piece of wire, the dimensions of length and diameter are dependent: The location ofthe wire on the diameter axis depends on its location on the length axis, and vice-versa. However, it is possible to start from scratch and manufacture a wire of virtually any length or any diameter. Therefore, for all possible pieces of wire, the dimensions of length and diameter are independent. Restated, whether dimensions are dependent or independent depends not only upon the axes chosen but also upon the nature of the subject matter being described in those dimensions.

As another example, recall the five-dimensional automobile described above. Its location in the five-dimensional space (length, width, height, weight, seats) was given as (17, 7, 6, 2,000, 5). Now, if the manufacturer of the auto tried to reduce its fourth-coordinate weight, it would be likely that one or all of the first three coordinates would be reduced, too. For example, after going from 2,000 kg to 1,500 kg, the new location in five-dimensional space might go to (16, 6.5, 6, 1,500, 5). This is meant to show that the five dimensions describing our automobile have been made mutually dependent, in that weight could not be changed by so much without also changing the values of other dimensions.

In fact, considering all possible automobiles, it seems certain that, in the units given, none of them ever would have a weight coordinate value which was less that its length coordinate value -- or less than the value of any of its first three coordinates. An automobile with coordinate values (17, 7, 6, 20, 5) probably would be physically impossible, except maybe for a styrofoam model of it. We see that some of the dimensions of our automobile are dependent by physical necessity.

Also, any automobile with a location such as (17, 2, 6, 2,000, 5) in the five-dimensional space above might make a good signboard display, but it never would sell to a driving customer. So, not only are the five-dimensional locations of all possible automobiles subject to certain physical dependencies; but, also, the locations are subject to certain social dependencies defined by customer expectations of just what constitutes a sellable automobile. On two counts, then, physical and social, the five dimensions describing our automobile are mutually dependent, regardless of which particular auto happens to be the subject matter being described. As will be recalled, this was not the case for the two-dimensions (length, width) of all possible wires.

Now looking again at the above eight-dimensional automobile, it is reasonable to expect that the owner's IQ will depend to some extent on the two GRE scores, in the sense that IQ and GRE should be correlated. For example, it is extremely unlikely that any owner would score a 153 IQ and also only 200 on both sections of the GRE. In our given example, the owner scored a 153 IQ, 217 GRE verbal, and 780 GRE quantitative; admittedly, these are unusual scores for anyone -- but, they are more "usual" than, say, 153, 200, 200. We expect IQ and GRE scores to correlate somewhat; and, the less the correlation, the less likely are we to feel that the scores might be accurate.


Looking at the scores actually reported, we might explain the owner's high IQ to some extent by the great quantitative skill suggested by the 780 quantitative score. If the score had been only 200 on both sections of the GRE, however, we would be at a loss for a simple explanation. Given the actual 153, 217, 789 scores, we might guess that the owner was sick or absent for part of the verbal section of the GRE. Alternatively, if we later found that a large number of GRE test-takers also scored extremely low on the verbal section, we might decide that the GRE test itself was in need of revision. Or, maybe we might examine the owner's component scores on the IQ test, looking for some strange imbalance in the performance there.

Otherwise stated, we expect a correlation between IQ and GRE test scores; and, when it does not appear, we feel that something may be wrong -- either with the person(s) or with the test. In effect, we feel that the three dimensions of IQ, GRE verbal, and GRE quantitative should reduce to perhaps two independent dimensions possibly resembling the verbal and quantitative sections of the GRE. If we do feel this, if we feel that the auto owner has scored results which seem somehow unbalanced, then we are feeling the way a factor analyst might feel upon setting out to track down a personality trait -- or theway Eysenck might feel as he searched for the dimensions of personality.

Reduction of Dimensions

We discuss here how the technique of reduction of dimensionality might work in a simple situation.

Let us consider two dimensions which correlate very highly when we locate people according to them. For example, we shall use the dimensions Stanford-Binet IQ and Wechsler-Bellvue IQ. According to Berelson and Steiner (1964, p. 211), measurements inthese two dimensions correlate about +.85. Let us then draw two orthogonal axes along which our two dimensions can be measured, and let's plot some hypothetical people's locations accordingly. See Figure 9 below.


Figure 9. Hypothetical Stanford-Binet (S-B) and Wechsler-Bellvue(W-B) IQ scores for a large group of subjects.

In Figure 9, each point represents one person's performance on the two IQ tests. The point corresponding to each person is located in the two-dimensional space (plane) by means of that person's coordinates (S-B, W-B). The points lie almost on a straight line, which reflects the fact that the tests are highly correlated. The slope of the line is about 1 (viz., about 45o from either coordinate axis), and this slope reflects the expectation that people will tend to get the same score on both tests; people's two coordinates, S-B and W-B, tend to be equal. The points are especially heavily concentrated in the region (100,100) because IQ scores on both tests tend to be normally distributed with mean 100; because of this normal distribution, more people tend to score around (100, 100) than, say, around (50, 50) or (150, 150).

At this point, one might recall the discussion above concerning Figure 2 through Figure 6. There, we found that we needed two orthogonal lines (axes) to locate the threepoints P, Q, and R in that plane; we could not draw a single line through all three points.Looking again at Figure 5, recall that we found that if we tried to get by with just one line L to locate all three points, we could do very well for points P and Q, which are shown there exactly on L, but that we would be considerably in error if we claimed that point R was even near to L. Our best claim would be that R was at point S in Figure 6.

Looking again at Figure 9, we can see that all the points plotted lie very close to the straight line M, which has been drawn at a 45o angle to the S-B and W-B axes. No person's coordinates fall very far from the line M -- again, because everyone's S-B and W-B results in fact were highly correlated.

Therefore, we will not be much in error if we use only one axis, the line M, to locate all

450

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100 150

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M


the peoples scores which were plotted in Figure 9.So, we can reduce the two-dimensional

space of Figure 9 to a one-dimensional spaceconsisting of the line M. This reduction willlead us only to very small errors in locatingindividual persons by IQ according to their S-B or W-B scores.

Figure 10 illustrates this reduction of the(S-B, W-B) space to M-space. The individualscores from Figure 9 are retained in Figure10 for clarity; however, the one-dimensionalnature of the new IQ space actually requiresthat the location of each person's score mustbe exactly on the line.

In Figure 10, the line M has been renamedto "IQ", because it is IQ scores which arelocated on that line. As before, the IQscores are approximately normallydistributed along IQ with a mean of 100.

As a final comment on the IQ space M ofFigure 9, it might be mentioned that whenever we have either a person's Stanford-Binet or Wechsler-Bellvue score, we can locate that score on the one-dimensional IQ space of Figure 10. If we have both an S-B and a W-B score for someone, we can add these scores and divide by two, thus finding that person's average (mean) IQ score for both tests; this is an easy way of locating that person in the one-dimensional IQ space of Figure 10. For example, a person with location (122, 126) in the two-dimensional (S-B, W-B) space of Figure 9 could be located at the point (123 + 125)/2 = 248/2 = 124 in the one-dimensional IQ space of Figure 10. The two-dimensional location reduces to a meaningful one-dimensional location with very little error.

Another way of saying that the S-B and W-B IQ scores are highly correlated with one another, then, is to say that both scores each are highly correlated with the single dimension of "IQ" as measured along the line M of Figure 9. If we know just the single IQ score, we also will know both the S-B and the W-B scores with very little error.

After these long and hopefully not too over-simplified preliminaries, we now can turn to a discussion of Eysenck's trait/type theory proper.

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IQ

Figure 10. The one-dimensional space Mfrom the scores of Figure 9 renamed to

"IQ".


Eysenck's Approach to Personality

General Program

Personality

By Eysenck's own definition, "Personality is the more or less stable and enduring organization of a person's character, temperament, intellect and physique, which determines his unique adjustment to the environment" (Eysenck, 1953, p. 2).

Personality, then, is a stable organization of things -- the way, perhaps, a crystal is a stable organization of atoms. Or the way, perhaps, the periodic table is a stable organization of chemical elements. Or the way, perhaps, that the concept of "oxygen" is a stable organization of phenomena such as the experimental phenomena p, p', p'', etc. of the section on hypothetico-deductive method above. Eysenck explicitly classifies himself as an atomist or elementalist, as opposed to a gestaltist or an organismicist (Eysenck, 1952, p. 276). Eysenck believes in the uniqueness of the individual personality; but, unlike Allport, for instance, he denies it any mystical significance. The unique individual, for Eysenck, is merely "the point of intersection of a number of quantitative variables" (Eysenck, 1952, p. 18).

On the other hand, Eysenck does value the doctrine of the "total personality", at least to the extent of recognizing that "partial approaches lead only to partial understanding . ... Investigations [should encompass] all and every type of factual and objective information which may be used to support or refute the hypothesis under investigation" (Eysenck, 1953, p. 319).

So, here we have the physical sciences metaphor full-blown: Individual personalities are "points located in some n-dimensional personality space"; personalities are "enduring organizations of phenomena"; and, the nature of the organization of personality, as well as the locations of individual personalities, are accessible by means of guessing and then testing ones guesses. Personality can be analyzed by means of the hypothetico-deductivemethod.

Personality Research

According to Eysenck, then, his aim is "to discover the main dimensions of personality, and to define them operationally, i. e., by means of strictly experimental, quantitative procedures" (Eysenck, 1952, p. 1; see also his p. 42, and his 1955, p. 4). Eysenck will implement his elementalistic approach to personality organization and to psychiatric diagnosis as follows: (a) By determining the required number of independent dimensions of personality; (b) by locating the dimensions (viz., their axes) properly; and (c) by measuring them reliably and accurately (Eysenck, 1952, p. 284).

Eysenck will carry out the specified determination, location, and measurement of the dimensions of personality by using factor analysis performed upon objective data


gathered during large-scale studies of operationally-defined phenomena (Hall and Lindzey, 1957, pp. 389 - 390).

The Hierarchical Organization of Personality

Factor analysis will not be discussed as such in the present paper. A good overall presentation of this subject is the one by Gorsuch (1974) cited in the References below. Very briefly, given a matrix of some kind, say 3 x 3 (3 dimensions by 3 factors each, for example), factor analysis allows the data to be transformed to its best, most quantitatively useful arrangement. Often, a factor analysis can convert the nine originaldata of a 3 x 3 matrix to just three averaged values (~dimensions) lying on a diagonal of the matrix:

Figure 10a. An arbitrary 3 x 3 matrix converted to one withonly three significant values (dimensions): A', B' and C'.

On the basis of factor analysis, and under the influence of the works of Jung, Kretschmer, and Allport, Eysenck concludes that human personality is a hierarchical organization of actions and dispositions to act.

At the bottom of the hierarchy are behavioral phenomena he refers to as specific responses. Specific responses are behavioral acts which are observed to recur under similar circumstances, or, at least, which tend to so recur. Specific responses tend to recur in identical groups, and these groups are referred to as habitual responses, the next higher phenomenon in the hierarchy. Sets of habitual responses, in turn, are organized as fairly abstract phenomena called traits. Some typical traits are named "persistence", "rigidity", "subjectivity", "shyness", and "irritability" (Eysenck, 1953, p. 13; see also p. 318).

Traits, according to Eysenck, are theoretical constructs based on observed correlations among habitual responses. These traits, in turn, are organized into the highest-order constructs in the hierarchy, which are the types. Eysenck has given the dimensions corresponding to his primary three types the names, "intraversion-extraversion", "neuroticism", and "psychoticism". One assumes that each of these dimensions might be measured as greater than or less than zero, depending on the characteristics of the individual who is assumed to possess them. A detailed discussion of the Eysenck types isavailable at en.wikipedia.org/wiki/Eysenck_Personality_Questionnaire, in which the types are named E (extraversion/introversion), N (neuroticism/stability), and P (psychoticism/socialisation) according to the later work of Eysenck and Eysenck (1975).

a b c

d e f

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~0 B' ~0

~0 ~0 C'


The four levels of hierarchy of personality organization -- specific responses, habitual responses, traits, and types -- correspond respectively with Eysenck's error factor, specificfactor, group factor, and general factor of his factor analysis. The reader should see Eysenck (1953, pp. 12 - 14) for a diagram and discussion of this hierarchy, which also is mentioned by Hall and Lindzey (1957, p. 384). One might note the resemblance betweenEysenck's personality hierarchy and Clark Hull's "habit-family hierarchy" (e. g., Osgood, 1953, pp. 612 - 614). Hull also is noted for his hypothetico-deductive approach (Hilgard and Bower, 1966, p. 146).

Contrast with a Less Experimental View

It can not be overemphasized that the traits and other levels of Eysenck's personality hierarchy are theoretical constructs. True, they are based on observation, but they are constructs of the observer nevertheless. As an example of a contrasting view, Gordon Allport agrees that the notion of trait is related to that of correlation (according to Eysenck, 1953, p. 9) and also agrees that traits must be identified by means of inference (e. g., Hall and Lindzey, 1957, p. 267); however, Allport's traits really exist in the person. For Allport, traits of personality are properties of the person itself and are the "ultimate realities of psychological organization" (Hall and Lindzey, 1957, p. 264).

As an example, one may contrast these views on the issue of individual uniqueness: ToEysenck, individual uniqueness is a very strongly supported hypothesis -- strongly supported because each person will have a different, unique set of coordinates, provided the individual is observed and measured closely enough. To Allport, people are like integers, in the sense that it is a mathematical law that any integer (whole number) can be factored into prime numbers in no more than one correct way. The integer 33 equals 11 x 3 and only 11 x 3; the integer 16 equals 2 x 2 x 2 x 2 x 2 and only this; 39 = 13 x 3; 315 = 3 x 3 x 5 x 7; 17 = 17; etc. For Allport, people are integral: People have factors (traits); people each have one and only one set of factors (traits); people each are inherently unique; therefore, people have unique, inherent sets of factors.

One is tempted to describe these differences by observing that if Eysenck conceptualizes personality by means of a physical science metaphor, then Allport and others conceptualize personality by means of a purely mathematical metaphor.


Dimensions of Personality

The Freudian Dimension

The Freudian psychosexual soap opera, as it might be called, strings out all human personalities along a single dimension. This dimension measures the degree of psychosexual regression present in a person. As illustrated in Figure 11 below, Freudianpersonalities are located at various points along a single continuum which runs from normality, through neuroticism, and into psychoticism (see Eysenck, 1952, p. 33; also 1955, p. 5).

Figure 11. A Freudian one-dimensional personality space.

The Orthodox Psychiatric Dimension (ca. 1969)

According to Eysenck, orthodox psychiatry, in contrast to the Freudian approach, locates individual personalities in a two-dimensional space defined by the orthogonal axes shown in Figure 12 below. In that figure, one axis is shown running from normalityto neuroticism, and the second is shown running from normality to psychoticism (see Eysenck, 1952, p. 33; 1955, p. 5).

Figure 12. An orthodox psychiatric two-dimensional personality space.

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MatureInfantile regression

– +

psychotic neurotic normal

PQ

R

psychotic

neuroticnormal


According to what Eysenck calls orthodox psychiatric theory, then, these personality states are possible: (a) a person may be not at all neurotic and yet be somewhat psychotic(point Q, Figure 12); (b) a person both may be neurotic and psychotic (point P, Figure 12);or, (c) a person just may be extremely neurotic (point R, Figure 12).

Thus, the orthodox psychiatric approach to personality contrasts with Freudian psychoanalytic theory, which latter reduces the orthodox views of psychoticism and neuroticism both to manifestations of a single underlying factor, degree of psychosexual regression.

Eysenck's Dimensions

As already explained, according to Eysenck's hierarchical theory, personality types are inferred from the observed organization of personality traits. For Eysenck, traits are general factors corresponding operationally to test scores (Hall and Lindzey, 1957, p. 385), and the importance of test scores is that they correlate and reveal the nature of the underlying personality types. Most of Eysenck's attention on this subject is devoted to these personality types which, in fact, he takes as defining the axes constituting his dimensions of personality.

As in en.wikipedia.org/wiki/Eysenck_Personality_Questionnaire, the traits which are associated with Eysenck's three dimensions are represented this way:

Psychoticism Extraversion NeuroticismAggressive Sociable AnxiousAssertive Irresponsible Depressed

Egocentric Dominant Guilt FeelingsUnsympathetic Lack of reflection Low self-esteemManipulative Sensation-seeking Tense

Achievement-oriented Impulsive MoodyDogmatic Risk-taking HypochondriacMasculine Expressive Lack of autonomy

Tough-minded Active Obsessive

In a 1947 study of ten thousand normal and neurotic subjects, Eysenck used factor analysis to reduce his data to the effects of two major independent personality factors (Hall and Lindzey, 1957, p. 386). Following Jung's lead (Eysenck, 1953, pp. 12 - 22), Eysenck named these factors "introversion-extraversion" and "neutoticism". These two factors thus defined two independent dimensions of personality. A later study in 1952, conducted with improved personality tests, revealed the presence of a third independent dimension of personality which Eysenck named "psychoticism" (Hall and Lindzey, 1957, p. 388).

Eysenck's resulting three-dimensional personality space in graphed in Figure 13 below.


Figure 13. Eysenck's three-dimensional personality space(after Eysenck, 1952, p. 285).

Compare Figures 12 and 13. Note that in Figure 13, the extra dimension of "intraversion-extraversion" enables this factor to be taken into account when evaluating apersonality. For example, assuming the importance and independence of the intraversion-extraversion dimension, it can be seen that the ideal orthodox psychiatrist, with only two dimensions of personality available (as in Figure 12), often would err in a diagnosis -- particularly in diagnosing (locating) people who were extremely "intraverted"or "extraverted". This error may be compared with the error one would make in graphing Figure 2 as Figure 7 in the Preliminary discussion of dimension above.

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Criterion Analysis

It has been mentioned that Eysenck's traits correspond to test scores which, when correlated and factor-analyzed, yield his types -- his dimensions of personality. It has not been mentioned that it is Eysenck's own unique approach to factor analysis, called criterion analysis, that he has used to apply the hypothetico-deductive method in order toconverge on stable psychological phenomena -- hopefully to use these phenomena to build an accurate and lasting science of personality.

Background

In the examples above, we have assumed the existence of definite axes which we used to locate various points. With real-world data, though, the number of axes (independent dimensions) involved and the location of the data points relative to those axes both are unknown initially. The purpose of factor analysis is to use the available data to establish the number and the location of those axes (Kerlinger, 1964, p. 663).

One simple way of factor-analyzing the results of a large set k of tests which were given to a group of experimental subjects is to plot the location of each test score on a separate, independent coordinate axis and then to find one or more straight lines along which might fall most or all of the test scores. The original k-dimensional space then can be reduced to a factor space the number of dimensions of which will be equal to or less than the number of those straight lines (Eysenck, 1955, p. 5). This method of reduction is essentially the same as that of the example above, in the section on dimension, in which the two-dimensional (Stanford-Binet, Wechsler-Bellvue) IQ space was reduced to a one-dimensional "generalized" IQ space corresponding to the single straight line M in Figure 9 above.

The problem with the method of reduction just outlined is that the resulting factors, or independent dimensions, which are isolated are not stable. As Eysenck has pointed out, in practice, if several of the k tests involved are omitted from the calculations, the axes defining the dimensions of personality will shift (Eysenck, 1952, p. 63). This shift would not be evident in the one-dimensional, one-factor, hugely- and closely-grouped IQ example given above in Figures 9 and 10; this mainly is because of the examples' simplicity. Thurstone, and later Cattell, attempted to overcome the problem of this shift by "overdetermining" the analysis of the correlation matrix by which the factor analysis was carried out (Eysenck, 1952, p. 70). Eysenck points out that this overdetermination (an analyses and re-analysis of the matrix) is in effect a rejection of the hypothetico-deductive method (Eysenck, 1952, pp. 70 - 71). Eysenck therefore substitutes his own method of criterion analysis to converge upon a set of stable axes with which to define his dimensions of personality. His method is described next.


Method

Human personality is a phenomenon and a problem. Eysenck begins his method of criterion analysis by the following five steps:

(a) First, Eysenck considers the problem carefully and then guessing, as a rough first approximation, what the sought dimensions of personality might be.

(b) Next, he selects two groups of human subjects which he assumes would be evaluated as considerably different in their locations along the axis of one of the hypothetical dimensions. These two groups presumably form a dichotomy along one dimension of personality; they are called criterion groups.

(c) Next, Eysenck then measures the two criterion groups, using large numbers of variousobjective tests; he uses measurements of motor performance, visual acuity, emotionality (autonomic nervous system responses), etc. Eysenck does not believe in questionnaires, projective tests, many rating scales, or other non-operational methods (e. g., Eysenck, 1952, pp. 37 - 41).

(d) He then correlates each of the individual tests with the dichotomy between the criterion groups. The correlations, or factor loadings, thus obtained are measures of just how sensitive the various tests are with respect to the dichotomy. Because the dichotomy is assumed to lie along of the dimensions of personality, the test correlationswith that dichotomy can be expected to reveal the extent to which the various test scores actually do measure the locations of the various subjects on the one dimension of personality in question. If few or none of the tests correlate highly with the dichotomy between groups, Eysenck concludes that the dimension in question is not valid.

(e) So, scores on tests which correlate highly with the dichotomy between the criterion groups thus may be taken to be first approximations of the true measurements of a location along the dimension of personality in question.

After all this, steps (a) - (e) then are repeated with new groups, selected using the first-approximation results so far obtained.

Repeated applications of criterion analysis are assumed to converge on, and eventuallyresult in, tests which reliably will define and measure a stable set of independent dimensions of personality. The dimensions finally isolated each are assumed to stretch more or less continuously between their two final criterion groups -- each two-group pair will be located near the end-points of its respective dimension.

Further information on criterion analysis may be found in Eysenck (1952, pp. 71 - 83) and in Hall and Lindzey (1957, pp. 391 - 393). Case examples of the application of criterion analysis may be found in Eysenck, 1953, chapter 4. A more recent, brief description of criterion analysis is available in Noaparast (1995, p. 15).


To summarize the above process of criterion analysis, first an initial hypothesis is formulated in regard to the nature of certain assumed dimensions of personality. Second, a deduction is made and experimental groups are selected on the basis of this deduction. Third, experimental measurements are taken to test the deduction. Fourth, the dimensional hypothesis is rejected if the deduction is shown false-to-facts; but, alternatively, fifth, if the deduction was not shown false, an induction (generalization) of the results is made in which certain tests are assumed to measure, or at least approximate, a stable psychological phenomenon which becomes the sought type, or dimension. This process is repeated as many times as necessary, each time with new knowledge and new insights into psychological phenomena. In short, the method of criterion analysis corresponds step-by-step with the hypothetico-deductive method of the physical sciences -- an example of which was presented above.

It was Eysenck's claim -- an echo of his theme -- that repeated application of criterion analysis to objective psychometric data eventually will reveal a set of accurate and stable dimensions of personality. Given such a set of dimensions, given an n-dimensional personality space in which to locate and incubate the patients, Eysenck claims that all the presently flourishing non-operational abuses in therapy and in personality theory willvanish -- withered away in the merciless white light of a true science of human personality.


SummaryEysenck's personality theory is based on the hypothetico-deductive method and on the

operational point of view. The hypothetico-deductive method and operationism both are highly successful (and highly idealized) tools of the physical sciences.

Eysenck's own experience as a clinician and his skill as a psychometrician combined in making him a powerful critic of theoretical and methodological abuses in all fields of personality. To counteract these abuses, Eysenck attacked the problem of the hierarchical organization of personality as a strict elementalist; he used, among other things, a hypothetico-deductive variation of factor analysis which he called criterion analysis.

By the method of criterion analysis, Eysenck hoped to isolate a stable, accurate set of dimensions of personality which could be used as a foundation for the development of a scientific theory of personality. These dimensions corresponded to his personality types. Fully developed, Eysenck's trait/type theory involves three major, independent dimensions of personality: introversion-extraversion, neuroticism, and psychoticism. Eysenk believed that the total personality must be taken into account in any personality theory; therefore, he conducted his research by means of large-scale studies which involved the measurement of many variables simultaneously.

Consistent with his physical-science, operational orientation, Eysenck became one of the founders of behavioral therapy.

Eysenck's approach to personality was influenced mainly by the work of Jung, Kretschmer, Allport, and the factor analysts, at least insofar as his trait/type theory was concerned.


ConclusionWhether Eysenck's physical-science approach to personality has actually worked

better than any of the myriad other approaches to personality is a question even now not yet decided.

Certainly, the physical science approach does work well in the physical sciences. Just as certain, too, is the fact that the physical world includes the "world" of personality as only one aspect of its vast complexity. The problem with personality theory is that personalities always interact. They reflect one another. Those who would study the personalities of others have been there and back; they already are too close to understand. People and chemicals can be kept from interacting; so, people can study thechemical elements, can operate upon them, and can learn to control them. But, people are people, and the study of the personality of another is inextricably mixed up with the study of ones self.

In therapy, perhaps a sort of Heisenberg uncertainty principle might apply: During any period of therapy, the interaction with the patient becomes strong, and the position ofthe therapist becomes somewhat uncertain. Perhaps therapy in general, like ordinary life, can not be operational -- because, in treating the patients, a therapist, to some extent, also is being treated. And, maybe individuals just can't treat themselves.

People are not atoms, and the physical science metaphor, like any other metaphor, can be fetched only so far. Then, we should use quotations: A "science" of personality.

. . . Eye to which all order festers, all things here are out of joint.Science moves, but slowly, slowly, creeping on from point to point.

Slowly comes a hungry people, as a lion, creeping nigher,Glares at one that nods and winks behind a slowly-dying fire.

Yet I doubt not thro' the ages one increasing purpose runs,And the thoughts of men are widen'd with the process of the suns.

What is that to him that reaps not harvest of his youthful joys,Tho' the deep heart of existence beat for ever like a boy's?

Knowledge comes, but wisdom lingers, and I linger on the shore,And the individual withers, and the world is more and more. . . .

-- Tennyson (Locksley Hall, 1842)

But, on the other hand, those are the words of the wealthy young man who looked at his love and peeped at the world with the original jaundiced eye.


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Russell, B. Human Knowledge -- Its Scope and Limitations. London: Allen and Unwin, 1948. (quoted at length in Eyesnck, 1952, pp. 78 - 81)

Russell, B. The Analysis of Matter. New York: Dover, 1954. (originally published in1927)


Skinner, B. F. A Case Study in Scientific Method. American Psychologist, 1956, 11, 221 - 233. Republished in B. F. Skinner, Cumulative Record. New York: Appleton-Century-Crofts, 1961.

Sneed, M. C. and Maynard, J. L. General College Chemistry. New York: Van Nostrand, 1944.

Walker, M. The Nature of Scientific Thought. Englewood Cliffs, New Jersey: Prentice-Hall, 1963.

eysenck's dimensions of personality

Documents

hypotheticodeductive

eysencks context

reduction of dimensions

preliminaries section

john michael williams

higher spaces

onedimensional spaces

twodimensional spaces