CATECHOLAMINE

EXCRETION,

CONSCIENCE

AND AGGRESSIVE

BEHAVIOUR*

FUNCTION

C. L. EKKERS Netherlunds Ins?irutg~~r Preoentioe Medicine TNO, Leiden, the ~erberlund~

Accepted for publication 14 October 1974

This report deals with a study - carried out among 46 12-17-year-old boys - of the relationship between: (I) the excretion of waste products of catecholamines (methyladrenaline and methylnoradrenaline) and creatinine, (2) aggressive behaviour in a laboratory setting, and (3) data obtained via a conscience-function questionnaire. The hypothesis that aggressive behaviour is positively correlated with methylnoradrenaline excretion was confirmed. As far as the conscience-function questionnaire was concerned, three dimensions could be distinguished. Methyladrenaline and methylnoradrenaline excretion proved to be reversely related to one of them, indicated as the “intropunitiveness-aggressiveness dimension’. Intropunitive subjects appeared to have a higher methyladrenaline and a lower methylnoradrenaline excretion than aggressive subjects. The aforesaid dimension also correlated signifi~ntly with cm&nine excretiona finding whichled to theinte~retatjon that aggressive people possess greater muscular strength than more intropunitively inclined people. However, no significant correlations between aggression scores and questionnaire scores were found. The results are discussed against the background of arousal theories of aggressive behaviour.

1. Introduction Ever since the research results obtained by Cannon (1929) became known, the relationship between emotional experiences and catecholamine excretion has formed an important subject of study. According to Cannon the adrenal medulla of animals reacting to fear- or rage-inducing stimuli produced adrenaline. After the discovery of noradrenaline, research efforts concentrated on the physiological differentiation between fear and anger. As far as research in humans is concerned, the research work performed by Ax and Funkenstein has been of fundamental importance. Ax (I 953) found that subjects whose anger or fear had experimentally been aroused, responded with different cardiovascular reaction patterns. Anger caused a reaction pattern similar to that which occurs after injection with *Secondary analysis of material collected by T. Fris, A. Slob and P. Winkel. This investigation was designed in consultation with Dr. A. Slob, chemist, attached to the Netherlands Institute for Preventive Medicine, under the supervision of whom the chemical analyses were also carried out. 15

16

C. L. Ekkrrs

noradrenaline, whereas fear aroused a response similar to that following adrenaline injection. Funkenstein (1955) and Funkenstein, King and Drollette (I 954) differentiated between anger directed outwards (anger-out), anger directed inwards (anger-in) and fear. Subjects who responded to a stress situation with anger-out were found to show cardiovascular reactions resembling those after injection with noradrenaline. The reactions of subjects who responded to the same situation with signs of anger-in or fear most closely resembled the reactions of people responding to an injection with adrenaline. The hypothesis formulated on the basis of these findings was that an emotional state which can be characterized as anger-out will be correlated with an increased noradrenaline excretion, whereas fear or anger-in will be correlated with an increased adrenaline excretion. Ever since it has become possible to analyse the waste products of catecholamines in urine, this hypothesis has been frequently tested. A review of the research studies in this area has been given by Schildkraut and Kety (1967). Although the results obtained have not always been equally clear, it seems that a rise in adrenaline excretion will usually occur during fear and in unpredictable threatening situations, whereas an increase in noradrenaline excretion may occur if the person concerned is angry or finds himself in a challenging, though predictable situation. Another line of study involves the relationship between excretion variables and the more constant personality traits (as opposed to the previously discussed emotional states of short duration). These excretion variables can be measured either in stress situations or under neutral conditions. In line with the hypothesis mentioned before, one would expect extrapunitiveness’ (also called ‘aggressiveness’) to be positively correlated with noradrenaline excretion (seen as a personality trait, and intropunitiveness’ and anxiety with adrenaline excretion (as a personality trait). Cohen, Silverman, Waddel and Zuidema (1961), Silverman and Cohen (I 960), Silverman, Cohen, Zuidema and Lazar (I 957) and Silverman, Cohen, Shmavonian and Kirshner (1961) reported that subjects with a high aggression score on a revised version of the thematic apperception test (TAT) had a higher noradrenaline excretion than subjects with a low aggression score. Likewise, subjects with a high anxiety score proved to have a higher adrenaline excretion than subjects with a low anxiety score. Frankenhaeuser and Kareby (1962) used a sentence completion test in order to measure extrapunitiveness and intropunitiveness. They could find no relationship with catecholamine excretion. ‘By ‘extrapunitiveness’ is meant the tendency to direct one’s feelings ofanger towards others, a tendency which may result in aggressive behaviour. 2By ‘intropunitiveness’ is meant the tendency to direct one’s feelings of anger towards oneself.

Bloom, Von Euler and Frankenhaeuser

(1963) in their study among para-

troop trainees, found that men who were characterized as extrapunitive by their colleagues and superiors produced more noradrenaline under stress

conditions, whereas men who described themselves as intropunitive produced more adrenaline. However, the reliability of the ratings used to measure intropunitiveness and extrapunitiveness was so low that no definite conclusions could be drawn. Frankenhaeuser and Patkai (1965) could find no relationship between catecholamine excretion and personality ratings with regard to aggressiveness and anxiety. Fine and Sweeney (1967) studied the relationship between socio-economic background of soldiers and their catecholamine excretion. According to these authors, methods of upbringing in lower socio-economic milieus promote the development of aggressiveness which consequently leads to a greater tendency towards aggressive behaviour in later (adult) life. This reasoning led them to the hypothesis that adults from lower socio-economic status groups will have a higher level of noradrenaline excretion than adults from higher socioeconomic status groups. However, they did not find a relationship between socio-economic background and adrenaline (A) or noradrenaline (NA) excretion, but only with the NA/A quotient3. For subjects with a lower socio-economic background a higher quotient was found. Since measurement of aggressiveness was not carried out, the study hardly seems to provide a basis for drawing conclusions about a relationship between aggressiveness and catecholamine excretion. in another study among soldiers carried out by Fine and Sweeney (1968), subjects with a high TAT aggression score were found to have a higher noradrenaline excretion than subjects with a low score. This time, the relationship with NA/A was not significant. For all the studies mentioned so far, the level of aggressiveness was either determined by means of ratings or a projection test, or derived from information about the subjects’ socio-economic backgrounds. Only those researchers who made use of the TAT, whether or not in a revised form, obtained significant and interpretable results. From the literature on aggression it is known that correlations between various measuring instruments of aggression are generally low (e.g. Leibowitz (1968)). it seems useful, therefore, to study whether the relationship between aggressiveness and catecholamine excretion can be demonstrated only by means of the TAT, or whether more direct measuring techniques, for instance a behavioural assessment of aggressiveness, will confirm the supposed relationship with catecholamine excretion. The aim of this study was, therefore, to investigate the relationship between catecholamine excretion and scores on a behavioural measurement of aggres3There is reasonto believe that adrenaline and noradrenaline have a reverse effect, so that the ultimate effect is determined by the relationship between the two substances, e.g. NA/A (Gellhorn, 196.5).

IX

C. L. Ehhars

siveness, and to specify the roles of adrenaline and noradrenaline in this relationship. Aggressive behaviour was defined as a ‘response that delivers noxious stimuli to another organism’ (Buss, 1961), which, for the purpose of this study was operationalized as ‘the administration of irritating noise stimuli to a stooge’. The hypothesis to be tested was that there exists a positive relationship between the amount and intensity of aggressive behaviour as shown on a measurement of aggression and the excretion of noradrenaline. Exploratorily the influence of the adrenaline excretion level on the relation between noradrenaline and aggressiveness was investigated (see footnote 3). This problem can be studied in various ways: either by calculating the correlation between the aggression variable chosen and the NA/A quotient (Fine and Sweeney, 1967, 1968), respectively; between the aggression variable and the A/NA as well as the NA/A quotients (Schulz and Strobach, 1970; reaction by Fine and Sweeney, 1971); or by determining partial correlations. The results of both techniques will be reported. Another item of exploratory study formed the relationship between excretion variables and aggression scores on one hand and the results of an adjusted version of Mik’s (1965) conscience-function questionnaire on the other. In this questionnaire a description is given of three near-aggressive situations. The respondent is asked to state the reasons why, in his opinion, the person described did not behave aggressively, whereby he can choose from six alternatives to be rank-ordered according to degree of probability. The idea behind this is that the respondent will make his choice in accordance with his own reactions to similar situations (projection). The alternatives have been chosen to agree with six aspects of man’s conscience function, as distinguished in psychoanalytic theory: (1) the super-ego (SE), i.e. the (mainly unconscious) forbidding part of the conscience; (2) the ego-ideal (EI), i.e. the more conscious striving at identification with one’s parents or with others; (3) the primary narcissistic ego-function (PNE), the taking into account of unpleasant consequences for oneself; (4) social-mindedness (Sot), i.e. the taking into account of the interests of others ; (5) the Triebangst, i.e. the fear of being overwhelmed by one’s own impulses, which indirectly forms a measure of one’s drive strength (DS); and (6) the secondary narcissistic factor (SN), i.e. the fear of unfavourable reactions of the outside world. Fris and Op den Velde (1969), who, in their study among psychiatric patients of a military hospital checked the relationship between the answers to this questionnaire and aggressiveness, found that patients who had previously been convicted for an aggressive offence had a significantly lower SE score

Catecholumine excretion and aggressive behaoiorrr

19

than patients without such a history who seldom showed physically aggressive behaviour. The first group also had a higher DS score, although not significantly so. These results are in agreement with the Freudian drive model, whereby the presence or absence of aggression is dependent on the severity of the aggressive drive (DS) and the strength of the drive-controlling functions, such as of the super-ego (SE). We see here a formal resemblance to the previously mentioned physiological model (based on correlations found between personality variables and the NA/A quotient), according to which adrenaline and noradrenaline might have a reversed relationship with aggressive behaviour. In this study, the interrelationship between the various functions mentioned in the questionnaire will be analysed as well as their relationship to aggressiveness and catecholamine excretion. 2. Method This study was carried out as part of a more extensive investigation into the growth and development of male adolescents (Slob, Wafelbakker and Van Gelderen, 1973, Winkel and Slob, 1973; Slob and Winked, 1973). The data on aggression and conscience function were collected by Fris, and those on cate~holamines by Slob and Winkel. The subjects were 46 12-17-year-old boys, all pupils of a lower technical school in Leyden. 2.1. Catechoiamines In urine samples three waste products of catecholamines were determined, i.e. methyladrenaline (from adrenaline), methylnoradrenaline (from noradrenaline) and vanilyl-mandelic acid (from adrenaline and noradrenaline and from methyladrenaline and methylnoradrenaline), to be referred to as MA, MNA and VMA, respectively. In addition, creatinine excretion4 was determined. MA and MNA were determined instead of A and NA because the original aim of the study was to find normal values for the excretion of MA and MNA (Winkel and Slob, 19’73). The urine samples were collected in three fractions spread over 24 hr: a day fraction, an evening fraction and a night fraction. No restrictions were imposed upon the boys as far as their eating, drinking, and smoking habits or other activities were concerned. After sampling, hydrochloric acid was added until pH 3 was reached; the samples were then stored at -20°C. Total MA and MNA were determined in 30 ml of urine following hydrolysis according to the combined methods of Coward, Smith and Wilson (1964), Coward and Smith (1966) and Perry, Shaw, Walker and Redlich (1962). VMA excretion Treatinine is an end product of the catabolism of creatine, which is concentrated in the muscular tissue. Creatinine excretion is often used as an index of the quantity of someone’s muscular tissue. In the sample population studied, creatinine excretion proved to be highly correlated with the subjects’ weight (r = 0.92).

was determined in 5 ml of urine using the method described by Moolenaar (1963). The catecholamine data were not adjusted to standard units of creatinine. For further details see Winkel and Slob (1973). 2.2. Measurenwnt of aggression The subjects took this measurement on the same day (a.m.) as the catecholamine measures. They were admitted to the experiment room four at a time. They had been told that their pa~icipation was needed for an investigation into the effect of irritating noise upon visual acuity. To this end they were asked to sit down behind a table, upon which a box with six buttons, numbered l-6, had been placed. At a distance of approximately 5 m was a panel on which some horizontal lines of various lengths had been printed, indicated A-l]. A female assistant (A) to the experimenter was sitting in front of the panel, wearing headphones. The subjects were told that, since the panel was placed at an angle above her head, A could see the lines less clearly than they could. The actual experiment consisted of the experimenter calling out two letters, after which A had to indicate by means of a lamp which of the two lines in her opinion, was the longest. If the subjects agreed with her decision, they had to push button I ; if not, they had a choice from buttons 2-6, which would, as they believed, produce an irritating noise in A’s headphones, the more irritating as the number became higher. So that, ifthey thought A’s answer was incorrect. the subjects were free to choose the intensity level of the noise stimuli. There were two series of ten pairs of lines; the differences in length between the lines were difficult to see, but each series consisted of five objectively correct and five objectively incorrect decisions. In actual fact, these decisions were predetermined, and the experimenter handled the lamps on the panel of lines himself. Because the subjects could not be absolutely certain if A’s decision was right or wrong it could be expected that the number of noise stimuli would vary between the subjects. We expected some subjects to press a ‘noise button’ only when they were absolutely sure that it was an incorrect decision, and other subjects to press the ‘correct button’ only when they were sure A’s decision was correct. According to the definition of Buss (1961), mentioned before, the number and intensity of the noise stimuli can be taken as a measurement of the degree of aggressive behaviour. it has been proved that these kinds of aggression measurements have a certain validity with respect to aggressive behaviour in daily life (e.g. Shemberg, Leventhal and Eron and Semler, 1967; Wolfe and Allman, 1968; Williams, Meyerson, Baron, 1971). 2.3. Col.uc.it’nc’r-~irncfion yuesfionnairt~ The following three situations were described in the questionnaire: ( I ) Someone is accused by a friend ofsomething he has not done. He would very much like to slap the friend’s face, but he decides against this.

(2) A football player is forced to the ground in a very mean way by an opponent. He would very much like to hit the other player, but he decides against this. (3) A cyclist is cut off by a car driver who then has to wait for a traffic light. He would very much like to slap the waiting driver, but he decides against this. The subjects were asked to study these situations and then group for each situation the six reasons given below in order of probability. Each reason is followed by its abbreviated psychoanalytical meaning in parentheses. (a) because this would be bad conduct (SE), (b) because he would lower himself in his own eyes (EI), (c) because this could have unpleasant consequences for himself (PNE), (d) because he might seriously hurt the other one (Sot), (e) because he would probably go from bad to worse (DS), and (f) because people might criticize him for it (SN). 3. Results 3.1. Measurement of aggression The aggression score was calculated by multiplying the intensity of the noise stimulus (l-5) by the number of times this stimulus was administered, after which the sum of these scores was determined. In this way, three sum scores were calculated, i.e. one covering the first series of ten trials (Al), one covering the second series (A2), and finally, one covering the first and second series taken together (At). The average aggression scores were: for Al : A4 = 10.0 (median = 9.3, s.d. = 5.8, range = O-3.5); for A2: M = 9.9 (median = 8.8, s.d. = 5.4, range= l-25); and for At: M= 19.8 (median= 18.5, s.d. =9.7, range = l-50). The distributions are somewhat skewed to the low end of the scale. It was decided, however, to use the Pearson correlation coefficients in the further analysis, because these coefficients are not influenced markedly by small deviations from normality. The correlation between Al and A2 was 0.49, between Al and At 0.87 and between A2 and At 0.85. The reliability of the aggression measurement proved to be rather low. According to the Spearman-Brown formula for test lengthening, the reliability of At is 0.66. As far as the remainder of the analysis was concerned, it was decided to study the three scores independently. The aggression scores turned out to be unrelated to the background variables, age, height and weight. Because the aggression task was in fact also a perception task, in which the subjects could make errors (pressing button 1 after an error or pressing a higher button after a good answer of the stooge), it was checked, if the number of errors the subjects made was related to the aggression level or to the excretion variables. This appeared not to be the case. 3.2. Catecholamine excretion A detailed discussion of the results of this part of the study can be found in

C‘. L. Ekkers

22

Winkel and Slob (1973). For the purpose of this article it is sufficient to report that the excretion variables were approximately normally distributed and positively related with each other (Pearson’s r between 0.30 and 0.50). Lower correlations were found between catecholamine excretion and age, weight and other indicators of growth. 3.3. Relationship hetwren aggression and catecholamines In table 1, the correlations are given between the aggression scores and the excretion of MNA. The excretion results have been divided into results obtained during the day (d), evening (e), and night (n), and the total results for a 24 hr period. Our hypothesis postulated that there would be a positive relationship between noradrenaline excretion and the level of aggressive behaviour. In so far as we can regard MNA as an indicator of the excretion level of noradrenaline, we can consider this hypothesis to be confirmed. Because of the already mentioned skewness of the aggression variable the relationship between Al and MNA-24 hr was checked by means of a nonparametric measure of correlation (Spearman’s rho). No difference with Pearson’s r was found (rho = 0.39). The significant correlation between At and MNA-24 hr was found to be predominantly the result of the high correlation between MNA and AI. No explanation for this result can be found in the data. Maybe the aggression in the first series had a more impulsive character than in the second where cognitive factors possibly played a more important role. If we assume that impulsive aggression is more related to catecholamine excretion than aggression steered by cognitive processes, which is a reasonable assumption because the hypothesis is based upon a theory of emotion, then this phenomenon could be explained. However, more research will be needed to answer this question. Aggression proved to be unrelated to MA. No evidence could be found for a contrary effect of adrenaline and noradrenaline, the partial correlations between aggression and MNA remaining virtually at the original level when MA was kept constant. Calculation of the correlations with MNA/MA and MA/MNA did not yield higher correlations either. Furthermore, a significant correlation between A I Table Correlations

MNA-24 Al A2 AI

I.

between aggression and methylnoradrenaline excretion (n = 46).

0.39: 0.1 I 0.30*

*p < 0.05 (two-sided); (two-sided).

d 0.25* -0.01 0.15 I/I < 0.01

e

n

0.38: 0.11 0.29*

0.3510.18 0.3 I *

(two-sided);

$p < 0.005

Cotecholumine

excretion

23

nmi nggressicle hehor?iorrr

and VMA-24 hr was found (Y = 0.28). Since there exists a correlation between VMA and MNA, this is not so surprising. A multiple regression analysis of Al and At on MNA, VMA, creatinine and age produced the following results: MNA, VMA and creatinine taken together were found to account for 23 % of the variance of A I, which corresponds to a multiple correlation of 0.48. Creatinine acts as a suppressor variable here. In the case of At, the same three variables accounted for 13% of the variance, i.e. a multiple correlation of 0.36. In neither of these cases did age prove to play a role of any importance. 3.4. Conscience-function questionnaire The rank order-scores for each of the alternatives were summated over the three test situations described. Since the classification had to be done in the order of preference of 1-6, a high sum score indicated a low preference. In order to prevent possible confusion, the scoring was reversed so that a high rank number now corresponds with a high preference. The scores appeared to be approximately normally distributed. Table 2 shows the average sum scores. From this table it becomes clear that the item representing the PNE function received the highest scores, followed by the item for social directedness. We are now interested in the relations between the alternatives. A second question is whether certain dimensions can be distinguished in these six variables. The usual way to study this is to compute correlation coefficients and carry out a factor analysis. However, in this case this is not the proper method of analysis because the variables are not stochastically independent of each other. This is caused by the method of data collection (rank ordering), whereby each assignment of a rank number to an alternative limits (and thus partly determines) the choice of rank numbers for the other alternatives. A multidimensional unfolding analysis (MINI-RSA programme, Roskam, 197 1) is a good method of analysing rank-ordered data. For this analysis the subjects and stimuli (the alternatives offered) are represented as points in a multidimensional (here Euclidean) space. The orders of preferences chosen by the subjects are then defined for each subject as the order of the distances of the point that represents the subject in the space to each of the stimulus points. For six stimuli a representation in five dimensions is perfect. The aim Table 2. Average

Mean s.d.

sum-scores over the three situations described conscience-function questionnaire (n = 38*).

in the

SE

El

PNE

sot

DS

SN

10.3 3.7

9.1 3.7

12.7 2.8

11.4 3.6

10.3 3.3

9.2 3.7

*Eight subjects questionnaire.

did not follow instructions

when filling in the

24

C. L. Ekkers

of the analysis is to reduce the number of dimensions such that the orders of distances differ as little as possible from the actual orders of preferences of the subjects. As an index of this, a figure called ‘stress’ is used, which is the minimum of a function which can vary between 0 and I. The smaller the stress, the greater will be the correspondence between the configuration selected and the actual preference orders. Roskam (I 968) calls a stress between 0.05 and 0. I5 ‘good’, and under 0.05 ‘excellent’. An unfolding analysis was performed in two and three dimensions, the stress being 0.23 and 0.06, respectively. The results of the unfolding analysis in three dimensions are in table 3 and fig. 1. In fig. 1, three interpretable dimensions can be distinguished, i.e. (I) SE versus DS, (2) EI versus SN, and (3) Sot versus PNE. (I) In the first dimension the two extremes are formed by SE and DS. On the basis of the already mentioned projection mechanism and accepting the psychoanalytic interpretation of the items, we can say that someone with a high drive strength has a fair chance of possessing a weakly developed superego. Because in psychoanalytic theory the super-ego often is ascribed an intropunitive character we can regard this dimension as an intropunitivenessaggressiveness dimension. However, it must be said that within the psycho-

DS .

.DS

so?

Fig.

I.

Stimulus

configuration

. PNE

of the conscience-function

I

questionnaire.

25

Stimulus configuration

Table 3. of the conscience.function

Coordinates

SE DS El PNE sot SN

Distances

I

II

-0.82 I .06 -0.42 0.31 -0.13 -0.01

0.42 0.06 1.03 -0.17 -0.18 -1.16

To make interpretation

questionnaire.

111 0.06 0.25 -0.23 -0.68 0.79 -0.19

SE 1.93 0.78

1.47 1.18 1.80

DS

El

PNE

Sot

SN

1.84 I .22 1.33 I .68

1.48 1.61 2.23

1.54 1.15

1.40

-

easier, axes I and II have been rotated over an angle of 55”37’.

analytic system other interpretations are also possible. This is due to the fact that in psychoanalytic theory the concepts and their mutual relationships are inadequately defined, an inadequacy which makes the psychoanalytic system unsuitable as an explanatory model. However, an interpretation of the SE-DS dimension without making use of the psychoanalytic system - based, for instance, on the contents of the items (alternatives) alone - is equally difficult, since these items have been selected on the basis of assumptions derived from the psychoanalytic system. This problem is less relevant in the case of the other two dimensions, as their interpretation can indeed be based on the contents of the items (alternatives). (2) The second dimension, El versus SN, indicates by whom the behavioural norm is being imposed. If the emphasis is on the ego-ideal aspect, then the individual himself provides this norm; if the emphasis falls on the secondary narcissistic aspect, then the individual’s social milieu is to be regarded as the norm-providing entity. Admittedly, the norm for the ego ideal in psychoanalytic theory can be traced back to the social milieu as well, but in this case the norm has been internalized to such an extent that the individual is no longer fully aware of its origin. (3) The third dimension, Sot versus PNE, can be interpreted as an altruismegoism dimension : the individual decides against aggressive action, since this might be harmful either to himself or to the second party involved. 3.5. Conscience function and aggression No significant correlations were found between the conscience-function questionnaire and the aggression measurement, although the correlations of A2 and At with DS were in the theoretically expected direction (0.20 and 0.18, respectively). 3.6. Conscience function and excretion variables 3.6.1. Dimension 1 (SE versus DS). The majority of the correlations with SE and DS have opposite signs, which is not so surprising considering that these

two variables form the extremes ofa dimension (table 4). MA and MNA have a reverse relationship both with SE and 1X (although not all the correlations are significant). This can also be seen from the fact that the correlations with MNA/MA are larger than thecorrelations with MA and with MNA separately. Furthermore, MA and creatinine have a reverse relationship with SE and DS. A calculation of the partial correlations may elucidate matters (table 5). The highest correlations are found with MA, with creatinine and MNA kept constant. The correlations with MA (with MNA kept constant) were found to equal those for the MNA/MA quotient (with opposite signs). In conclusion it can be said that SE and DS correlate with MA, creatinine and MNA, whereby creatinine and MNA play a reverse role with regard to MA. A multiple regression analysis of DS upon MA (9 x), creatinine (23.7:‘;:) and MNA (6.4x1) explained for 39 x, of the DS variance - corresponding with a multiple R of 0.63. A multiple regression analysis of SE upon MA (9.4%). creatinine (5’j/,) and MNA (1.6’;/,) explained for 16:,;; of the SE variance - corresponding with a multiple R of 0.40. These results can best be explained by means of the SE-DS dimension being interpreted as the already mentioned intropunitiveness-aggressiveness dimension. According to the hypothesis formulated by Ax and Funkenstein (and adjusted to research into personality traits), there existed a positive relationship between intropunitiveness and adrenaline excretion and between aggressiveness and noradrenaline excretion. It follows that a dimension with intropunitiveness and aggressiveness as its two extremes would, as far as its aggressiveness pole is concerned. have to show a positive correlation with

Table 4. Correlation

SE DS

variables (n = 38).

of SE and DS with the excretion

VMA

MA

MNA

0.03 0.19

0. I5 -0.30*

-0.06

*p < 0.05 (two-sided);

0.10

Creatinine

MNA/MA

-0.22 0.2,:::

-0.23 0.44t

1-p i 0.005 (two-sided)

Table 5. Partial

SE DS

correlations

variables

MA (treat. const.)

MA (MNA const.)

MA (treat. and MNA const.)

MNA (treat. const.)

MNA (MA corlst.)

0.3 I * -0.52~

0.23 -0.44:

0.34t -0.599

0.03 -0.01

PO.19 0.35-i.

*p -c0.05 (two-sided): sided).

of SE and DS with the excretion

‘tp < 0.025

(two-sided);

:/I < 0.005

OI= 3X).

MNA (crcat. and MA const.)

(twc-sided);

-0. I4 0.31”

MNA/MA (cl-eat. const.) -0.28* 0.525

#p i 0.0005

(two-

Catecholamine

excretion

and aggressice

behaviour

27

noradrenaline excretion and a negative correlation with adrenaline excretion. For its intropunitive pole this would have to show a negative correlation with noradrenaline excretion and a positive correlation with adrenaline excretion. The results do indeed confirm these expectations. What they do not confirm, however, is the expected relationship of DS and SE with the behavioural measurement of aggressiveness as determined in this study. In the study carried out by Fris and Op den Velde (1969) mentioned before, such a relationship was found, however, albeit for a different measurement of aggression (i.e. aggressive offences). The relationship between creatinine and SE and DS was not expected. Since creatinine is a measure of the amount of muscular tissue, the conclusion seems justified that more aggressive and less intropunitive individuals have a larger amount of muscular tissue (muscular strength) than less aggressive and more intropunitive individuals. This conclusion is in accordance with ‘common-sense theories’ concerning the relationship between aggressiveness and muscular strength. 3.6.2. Dimension 2 (EI versus SN). None of the correlations between dimension 2 and the excretion variables reaches the 5 ‘A significance level. However, here too a reverse role of MNA and creatinine with regard to MA seems to exist, particularly as far as their relationship with the ego ideal is concerned. The partial correlation between MA and ET with creatinine and MNA constant indeed surpasses the 5 % significance level (r part = 0.31), which is about the same as the relationship found for SE. In view of the conceptual resemblance of super-ego and ego-ideal, and in view of the fact that the ego-ideal on the SE-DS dimension is situated relatively closely to the super-ego (see fig. l), this outcome is not surprising. 3.6.3. Dimension 3 (Sot versus PNE). Only the correlation PNE-VMA reaches the 5 ‘A significance level (r = 0.30), the correlation PNE-MNA stays just under this level (r = 0.23). This result would point towards a personality trait such as ‘egoism’ or ‘opportunism’ (or the ego function, in psychoanalytic terms) positively correlating with noradrenaline excretion. 4. Discussion In this study an attempt has been made to establish a relationship between a behavioural measurement of aggression and catecholamine excretion. The hypothesis formulated by Ax and Funkenstein which originated from and was tested in research into the emotional component of aggression (the emotional state, ‘anger’) was also confirmed in this type of study, based on aggressiveness measured in terms of behaviour. Since the study involved more or less permanent individual characteristics, catecholamine excretion was determined over a relatively long period (24 hr). For the measurement of aggression, no specific attempt was made to arouse an emotional state (for

instance, by means of frustration). It seems worthwhile to combine these two types of study in order to check whether there is a relationship between catecholamine excretion as a personality trait and the change which occurs in this excretion pattern during an emotional state and the corresponding changes in behaviour. Again in accordance with the (adjusted) hypothesis of Ax and Funkenstein, the results of a questionnaire measurement of aggressiveness on one dimension with intropunjtiveness pointed to the existence of a reversed relationship with adrenaline and noradrenaline excretion. A problem here is that the interpretation of the SE-DS dimension in terms ofintropunit~veness-aggressiveness is based on the psychoanalytic system with its inadequate definitions characteristic. Admittedly this interpretation does not unquestionably follow from the psychoanalytic system, but fits very we!! in the interpretation of the relationship found between this dimension and catecholamine excretion. There clearly seems to be a case, therefore, in favour ofa further comparison between the aforesaid questionnaire and other questionnaires on personality and aggression aspects. The high correlations found between the SE--DS dimension and creatinine and catecholamine excretion are suficient evidence for further research. furthermore, it can be said that the formal resemblance - indicated in the Introduction - between the psychoanalytic drive model and a possible physiological model of aggressiveness could not be proved. Adrenaline and noradrenaline excretion were found to be positively correlated (v = 0.50), whereas SE and DS were situated opposite each other on one dimension. Only in the case of noradrenaline excretion could a correlation be proved with the behaviourally measured aggressiveness; this time, no reverse effect for adrenaline excretion could be traced. There were no significant correlations between the SE-DS dimension and behaviourally measured aggressiveness. What was found, however, was a correlation between the SE-DS dimension and adrenaline as we!! as noradrenaline excretion. The lack of significant correlations between the intropunitiveness-aggressiveness dimension and aggressiveness measured in behavjoura! terms is in accordance with results described in the literature, where, in genera!, low correlations or no correlations at all are reported between questionnaire measurements and behavioura! measurements of aggressiveness (e.g. Leibowitz (1968)). Apparently, the concept ‘aggressiveness’ is so wide, that different operationalizations need not necessarily produce similar results. This appears also from the literature quoted in the Introduction, in which only one index of aggressiveness (TAT) is reported to show a relationship with catecholamine excretion. Another reason for the fact that in this investigation no relationship was found between the questionnaire assessment and the behavioural assessment may be that for the former the subject could choose between an intropunitiv~ (SE) and an aggressive (DS) reaction. whereas the

Cutechokm~ine excretion and uggressire hehtrrkmr

29

latter only focused on aggressive behaviour. An experimental set-up which would include the possibility of a (still to be operationalized) intropunitive reaction as well might bring to light the aforementioned relationship. In recent literature on aggression the concept ‘arousal’ has received more and more attention. By ‘arousal’ is meant a state of increased activation of the organism which can be induced by emotion-producing stimuli (e.g. a film or a frustration, Zillmann, 1971; Meuwese, 1973). This state is accompanied by a number of physiological reactions, such as an increase in pulse rate, blood pressure, rate of skin blood flow. Once this state has been induced it is supposed to help intensify aggressive behaviour, in much the same way as generalized drives are known to facilitate the expression of dominant responses (Hull, 1952; Zajonc, 1965). In this connection, it is interesting to know that arousal can be artificially induced by injection with adrenaline (Schachter and Singer, 1962), after which, as the situation requires, either euphoria or anger can be aroused. It may be important here to study the role of noradrenaline as well, since the present and previously carried out research has proved that emotional conditions and personality traits show different correlations with adrenaline and noradrenaline. It is still an open question, whether there is just one type of ‘general arousal’, or whether - possibly under the influence of adrenaline and noradrenaline - several types of arousal may be distinguished. In addition to research into arousal as a ‘state’ (either induced by an emotion-producing stimulus or injection), it would seem valuable to study arousal as a ‘trait’, e.g. in order to answer the question whether a permanently raised level of arousal has something to do with a personality trait such as aggressiveness.

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