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A method to elicit aggressive feelings and behaviour via provocation
69
Hdog~cul PsycholoR), 22 (1986) 69-79 North-Holland
A METHOD TO ELICIT AGGRESSIVE VIA PROVOCATION
Accepted
for publication
11 October
FEELINGS
AND BEHAVIOUR
1985
A technique is described which elicits hostility via provocation in a competitive reaction time task inco~orating a predetermined failure rate of 50%. When the subject loses he is exposed to a white noise which increases in intensity through the experiment. When he wins he is able to administer one of 8 levels of noise to his opponent. Heart rate and skin conductance level and fluctuations were monitored throughout the experiment. Self-ratings of mood. aggression and anxiety were completed both pre and post task. It was found that the task elicited hostility which could be measured behaviourally, physiologically and emotionally.
1. Introduction Aggression is a very difficult phenomenon to study under controlled conditions (Edmunds and Kendrick, 1980). A wealth of literature is concerned with definitions (Bandura, 1973; Hinde, 1974; Geen. 1976) but most authors agree that three components are necessary for behaviour to be defined as ‘aggressive’: a noxious stimulus, intent to harm and expectation of success in this objective. Although it may be difficult to produce aggressive behaviour in the laboratory, especially among otherwise stable, well-controlled individuals, they may nevertheless feel increased anger or hostility. This feeling should be measurable on mood change instruments whether or not it is admitted verbally, This experiment was aimed at setting up a laboratory paradigm which would produce aggression and at finding physiological, behavioural and emotional measures, with the object of assessing drug effects at a later stage. Taylor (1967) devised an interactive, competitive situation in which the subject undertakes a reaction time task in apparent competition with another subject. In this study we adapted his technique by adnlinistering white noise instead of an electric shock. It has been shown that noise delivered out of the subject’s direct control is a very potent noxious stimulus (Lundberg and Fran* Correspondence and reprint requests to Dr. A. Bond at above address. financially supported by the Medical Research Council of Great Britain.
0301-0511/86/$3.50
6:) 19S6, Elsevier Science Publishers
B.V. (North-Holland)
This
work
was
A. Bond md
70
M. La&r
/ Aggressron
elru~ed by prouocu~ron
kenhaeuser, 1978). The objective was to ascertain whether this modified technique would increase behavioural aggression and in addition to monitor its effects on physiological measures and a variety of self-reported feelings.
2. Methods
Nineteen subjects were studied, 9 males and 10 females with a mean age of 33 (range = 23-57) all employees of the Institute of Psychiatry. 2.2. Experimentul
situation and design
Each subject was told that he was engaged in a competitive reaction time task with a subject in another room. The subject was instructed to adjust a switch on his task board (fig. 1) at the beginning of each trial so that any of 8 intensities of noise (range = 70-105 dB) could be delivered. These noises, he was informed, would be administered to his opponent at the end of the trial if his reaction time was faster than this opponent’s: his opponent had similar privileges. Thus the subject realised that he might hear or administer a noise depending on the outcome of the competition and the magnitude of the noise could be varied by both competitors. In fact there was no opponent. The level of provocation was increased through the experiment. After the initial (no provocation) trial, the 24 trials were divided into 4 blocks of 6 trials each. On the first block, the noise level averaged 1.5; on the second block, 3.5
111*13141W+l Volume Volume to to other
set
by other
be delivered subject
0 Press
when
0 Set
volume
Fig. 1. Task board.
volume
set
0 Warning
0 Reaction
Timer
subject
and on the third and fourth, 5.5 and 7.5 respectively. actual noise on 50% of occasions within each block.
The subject
heard
the
the same sequence
of
2.3. Procedure All subjects events. (1) Green
received
light on
(2) Green button (3) Light display (4) (5) (6) (7)
25 trials.
on
Amber light on Red light on Red button Noise
Certain
measures
Each trial contained
- signal for subject to set the level of noise for their opponent. - subject presses when ready to proceed. of lights (1-S) was illuminated to - a number display the level of noise set by the opponent. - warning for R.T. stimulus. - R.T. stimulus. _ subject presses in response. _ administered on 50% trials.
were taken from these events:
(a) Setting time was the time taken from the onset of the green light to the subject pressing the green button indicating he has turned the switch onto his chosen setting. (b) Level set was that which the subject set for their opponent to receive on each trial. (c) Reuction time. The visual reaction time was measured in msec. The data from the 25 trials were summarized by a Pre Score (trial 1) and four subsequent scores, each representing the mean of 6 trials. A PDP 12A laboratory computer controlled the events in the experiment, recorded the other variables and administered the noises. 2.4. Physiological
measures
2.4.1. Heart period.The heart period was monitored throughout the experiment. During each trial, mean inter-beat-intervals (IBI) were taken around the significant events - Pre Green Light; Post Ready Button; Post Volume Display; Post Amber Light; Post Noise or No-Noise. These figures were averaged for blocks of 6 trials giving a Pre (trial one) score and 4 other readings. 2.4.2. Skin conductance level and fluctuations. The palmer skin conductance was recorded throughout the experiment on a Grass Polygraph as described previously (Bond and Lader, 1972). Two readings were taken within each trial at the beginning (Pre Green Light) and at the point of greatest change within the trial. The latter was expressed as a difference score from the pre trial level. These 2 scores were averaged across the 4 blocks of trials. The number of
12
Name
A. Bond and M. lader
Age . .
Date
/ A~gress~on elicited by prouocatran
Sex
I. Please rate the way you feel in terms of the dimensions given below 2. Regard the line as representing the full range of each dimension 3. Rate your feelings as they are AT THE MOMENT 4. Mark clearly and perpendicularly across each line ANGRY AFFABLE FURIOUS SOCIABLE AGGRESSIVE BELLIGERENT RESENTFUL PATIENT FRIENDLY SPITEFUL ANNOYED PLEASED REBELLIOUS Fig. 2. Aggression
PEACEFUL QUARRELSOME CALM UNSOCIABLE COOL-HEADED RESTRAINED TOLERANT IMPATIENT HOSTILE BENEVOLENT COMPOSED DISGUSTED COMPLIANT
_ _ _ _ _
_ _ rating
scale.
fluctuations greater than a certain criterion (1% of baseline level) was counted for 15 set at the beginning of the trial before the Green Light (Pre), for 15 see after the ready button (during) and for 15 set after the reaction time was recorded (post). These figures were then averaged across the 4 blocks of trials and divided into Noise and No-Noise conditions. 2.5. Suhjeclive
ratings
2.5.1. Mood Rating Scafe (MRS). The subjects completed a visual analogue mood rating scale of 16 items. For each item the subject had to make a mark along a 100 mm line and the score was measured in mm from the scale end to that mark. In addition 3 factors previously isolated from the scale. were analysed (Bond and Lader, 1974). 2.5.2. Aggression Rating Scale (ARS). This scale consisted of 13 items measuring feelings of hostility and was constructed in a similar way to the MRS (fig. 2). 2.5.3. Spielberger State Anxiety Inventory (SSAI). The SSAI was used with an instruction requiring subjects to indicate how they felt ‘at this moment’, (Spielberger, Gorsuch and Lushene, 1969). All three scales wese completed both before the competitive reaction time task and immediately after it. 2.6. Analysis of data Analysis of variance (sex, time and sex X time) was used to analyse the data for the variables which were measured on the 4 blocks of trials and for the ratings. Linear trends were examined.
A. Bond and M. Lader / Aggressmn
elrcired b?:prmocatwn
13
3. Results Only significant
results are shown.
(1) Setting time. The time taken by the subjects to set the noise level for their (2)
opponent decreased significantly through the experiment (p < 0.002) with a linear trend (p < 0.025). Level set. The level of noise that the subjects set for their opponent significantly increased through the experiment (p < 0.007) with a linear trend ( p < 0.01) (fig. 3).
3. I. Physiological
measures
3.1.1. Heart period: Post ready button. This is a waiting period: the subjects have selected the level of noise for their opponent and are anticipating their opponent’s setting. During this time, the heart period (HP) grew significantly longer through the experiment (p < 0.003) and in a linear fashion (p < 0.005). Post noise or no-noise. There was no significant change after the subjects heard a noise through the experiment i.e. increasing noise levels did not alter
8 7
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Trial
I
r
1
l-2
I
3-4 L.34
5-6
7-a
received
Fig. 3. Mean level of noise which the subjects administered blocks of trials (0-O) and the level which they received (-
-
to their opponent -).
over successive
A. Bond and M. Lnder / Aggression elrcited b.y prowcutron
14
I a.1
840
Q, \
_
‘1 ‘O-,.__
-0,
\
post \
820
-
no-noise
\
‘0 800
-
780 -
760 -
740
-
+
07,;
, 1
2-7
r
8 -13
14-19
, 20-25
Trials Fig. 4. The mean inter-beat-interval no-noise.
of the heart rate over successive
blocks of trials
post noise and
the subjects’ heart-period (fig. 4). When no noise occurred, the HP showed a progressive shortening over trials (p < 0.05) with a linear trend ( p < 0.06). When the two conditions were compared there was a highly significant difference between them (p < 0.0005) which did not change with increasing noise level. The HP was significantly longer when no noise occurred.
There was a significant difference between sexes on baseline skin conductance level ( p -=z0.02); the males having a higher level (X = 11.1) than the females (X = 7.5). There was no significant interaction of sex with time, both
by prooocution
A. Bond and M. Loder / A.ggre.won rlmted 1.1 -
10
-
0 0
///
0 -0
2.5
-
29
-
75
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:
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1
1.0 -
0 -13
2-7
14 -- 19
20 -25
0
I
!
we
During
Post
Trials
Fig. 5. The mean change in skin conductance level in microsiemens within each trial shown over successive blocks of trials (left). The mean number of fluctuations within trial shown for pre trial, ) and no-noise (- ~ -). during the trial and post noise (-
sexes increasing through the experiment (p < 0.001) with a linear trend (p < 0.006). When the change in SCL within each trial was analysed, the measure altered significantly through the experiment (p < 0.0005) (fig. 5). The difference from baseline increased over the successive blocks of trials i.e. as the noise became louder, and showed a linear trend ( p cc 0.006). Males had significantly more fluctuations both pre trial (p < 0.025) and during the trial (p < 0.005) but not post noise/no-noise. There was no significant interaction effect. There was no significant difference across blocks of trials through the experiment but there was a significant difference within the trials. The number of fluctuations increased from pre trial to the rest of the trial (p < 0.0001). There was also a significant difference between the noise and no-noise conditions ( p < 0.0002), with more fluctuations after the noise (fig. 5). 3.2. Subjective
ratings
There were no sex differences
on any of the rating
scales.
3.2. I. Mood rating scale The only item which showed a significant change on this scale was amicable-antagonistic: the subjects rated themselves as significantly less amicable after the task (p < 0.005). They also tended to show increased excitement and tension as measured by the factor 3 score ( p < 0.06).
76
3.2.2. Aggression
A. Bond and M. Lader / Aggressron elicited by prorocatron
ruting scale
Five items on this scale showed a significant change after the task: affable-quarrelsome ( p < 0.05); calm~furious ( p < 0.04); restrained-belligerent ( p < 0.04). All the other scales showed similar but non-significant changes. 3.2.3. Spielberger
SSA I
There was no significant change after scores were 35.8 (pre) and 39.6 (post).
the task on this scale. The mean
4. Discussion Our results show that the competitive reaction time task used in this experiment succeeded in eliciting hostility which could be measured behaviourally, physiologically and emotionally. The subjects came into the laboratory feeling alert, contented and calm (MRS), generally friendly and peaceful (ARS) and showing mild situational anxiety (SSAI). After the competitive reaction time task their self-assessments of alertness and contentedness did not change, but their interpersonal feelings did. They felt less amicable and friendly and admitted to feelings of hostility on the ARS. They rated themselves as more antagonistic towards the other person but not unhappy in themselves. Their anxiety scores did not change much but they did rate increased excitement and tension as would be expected from a competitive task. The behavioural measure of hostility in this experiment was the level of noise which the subjects set for their ‘opponent’. The subjects increased this setting in response to provocation. The subjects changed physiologically during the experiment. For the heart period, the change in arousal was greatest on the first trial; the HP shortening from 800 msec at the start of the trial to 740 msec after the noise (fig. 6). On subsequent trials, the subjects showed a similar pattern which changed significantly at only two points. After the subjects had set the noise level for their opponent their HP lengthened significantly through the experiment. The difference was small indicating that the variability between subjects was minimal. It occurred at a time of rest or waiting and may reflect the subjects’ anticipation of their opponent’s setting. The heart period after the noise differed from that in the no-noise condition. When no noise occurred, the HP progressively shorterned through the experiment. This is probably a fear reaction as the subjects anticipated receiving louder and louder noises and this proposition is confirmed by the even greater shortening when the noise actually occurred.
A. Bond and M. Lader
/ Aggresston
elrcited
71
trials
I.B.I. n 840
by pro~wution
2-7
-
820
800
-
780
-
‘0 \ \
Fig. 6. The mean inter-beat-interval of trials.
O\
0
trial
1
of the heart rate shown for trial 1 and the 4 subsequent
blocks
That males have significantly higher skin conductance levels than females has been reported before (Ward, Doerr and Storrie, 1983) but may simply reflect the sex of the experimenter, in this case female (Gale and Baker, 1981). Both sexes showed a significant increase in level through the experiment suggesting that the subjects were becoming more aroused physiologically through the experiment with no evidence of habituation. This was confirmed by the difference score in level which was measured on each trial and which also increased with mounting provocation. The number of fluctuations did not increase through the experiment but it did increase within each trial. The
subjects relaxed between trials (pre or resting measure) but arousal increased with the sequence of events and again the number of fluctuations was greater after the noise than when no noise occurred. Thus the actual noise increased heart rate, skin conductance level and fluctuations, confirming that it was a potent noxious stimulus. Our findings are similar to those found previously using shocks. We used the conditions which have been found maximal in producing socially mediated aggression e.g. increasing levels of provocation, equai ability as evidenced from a 50% defeat ratio (Epstein and Taylor, 1967), and found these conditions to elicit hostility following noises in a similar way to that found by the previous authors using shocks. This device therefore proved very useful in eliciting hostility. The subjects showed increased anger on behavioural, physiological and self-rating measures. The mood effects were inter-personal, directed outward and were not directed inward either in the form of sadness or anxiety. This lack of reported anxiety suggests that the arousal shown on the skin conductance measures is a concomitant of anger rather than fear or anxiety with the exception of the stress response to the actual noise. Interestingly the subjects experienced these feelings even though some of them suspected that there was no other person. It is possible that these subjects, who became sceptical during the experiment, directed their anger at the experimenter or perhaps in this automated age of computers, ‘space-invaders’ and the like, competing against a machine arouses as much aggression and frustration as competing against another human being.
References Bandura, A. (1973). Aggression. A Social Learning Analysis. Prentice-Hall: New Jersey. Bond, A.J. and Lader, M.H. (1972). Residual effects of hypnotics. Psychopharmacologia (Berl.). 25, 117-132. Bond. A.J. and Lader, M.H. (1974). The use of analogue scales in rating subjective feelings. British Journal of Medical Psychology, 47, 211-218. Edmunds, G. and Kendrick. D.C. (1980). The measurement of human aggressiveness. Wiley: New York; Ellis Horwood Ltd: Chichester. Epstein, S. and Taylor, S.P. (1967). Instigation to aggression as a function of degree of defeat and perceived aggressive intent of the opponent. Journal of Personality, 35, 265-289. Gale, A. and Baker, S. (1981). In Vivo or In Vitro? Some effects of Laboratory environments, with particular reference to the psychophysiology experiment. In: Christie, M.J. and Mellett, P. (Eds). Foundations of Psychosomatics. John Wiley and Sons Ltd: Chichester, 363-384. Geen, R.G. (1976). Personality. the Skein of Behaviour. Henry Kimpton. Hinde. R.A. (1974). Biological Bases of Human Social Behaviour. McGraw-Hill: New York. Lundberg, U. and Frankenhaeuser, M. (1978). Psychophysiological reactions to noise as modified by personal control over noise intensity. Biological Psychology, 6. 51-59. Spielberger, C.D., Gorsuch, R.L. and Lushene, R.E. (1969). The State-Trait Anxiety Inventory. Palo Alto, CA: Consulting Psychologists Press.
A. Bond md h4. Lader
Taylor, S.P. (1967). Aggressive and the tendency to inhibit Taylor, S.P. and Epstein. S. Medicine. 29. 514-525. Ward. N.G.. Doerr. H.O. and for depression. Psychiatry
/ Aggrmron
79
elicited by prococatm
behaviour and physiological arousal as a function aggression. Journal of Personality. 35, 297-310. (1967). The measurement of autonomic arousal. Storrie, M.C. (1983). Skin conductance: Research. 10. 295-302.
A potentially
of provocation Psychosomatic sensitive
test
Hdog~cul PsycholoR), 22 (1986) 69-79 North-Holland
A METHOD TO ELICIT AGGRESSIVE VIA PROVOCATION
Accepted
for publication
11 October
FEELINGS
AND BEHAVIOUR
1985
A technique is described which elicits hostility via provocation in a competitive reaction time task inco~orating a predetermined failure rate of 50%. When the subject loses he is exposed to a white noise which increases in intensity through the experiment. When he wins he is able to administer one of 8 levels of noise to his opponent. Heart rate and skin conductance level and fluctuations were monitored throughout the experiment. Self-ratings of mood. aggression and anxiety were completed both pre and post task. It was found that the task elicited hostility which could be measured behaviourally, physiologically and emotionally.
1. Introduction Aggression is a very difficult phenomenon to study under controlled conditions (Edmunds and Kendrick, 1980). A wealth of literature is concerned with definitions (Bandura, 1973; Hinde, 1974; Geen. 1976) but most authors agree that three components are necessary for behaviour to be defined as ‘aggressive’: a noxious stimulus, intent to harm and expectation of success in this objective. Although it may be difficult to produce aggressive behaviour in the laboratory, especially among otherwise stable, well-controlled individuals, they may nevertheless feel increased anger or hostility. This feeling should be measurable on mood change instruments whether or not it is admitted verbally, This experiment was aimed at setting up a laboratory paradigm which would produce aggression and at finding physiological, behavioural and emotional measures, with the object of assessing drug effects at a later stage. Taylor (1967) devised an interactive, competitive situation in which the subject undertakes a reaction time task in apparent competition with another subject. In this study we adapted his technique by adnlinistering white noise instead of an electric shock. It has been shown that noise delivered out of the subject’s direct control is a very potent noxious stimulus (Lundberg and Fran* Correspondence and reprint requests to Dr. A. Bond at above address. financially supported by the Medical Research Council of Great Britain.
0301-0511/86/$3.50
6:) 19S6, Elsevier Science Publishers
B.V. (North-Holland)
This
work
was
A. Bond md
70
M. La&r
/ Aggressron
elru~ed by prouocu~ron
kenhaeuser, 1978). The objective was to ascertain whether this modified technique would increase behavioural aggression and in addition to monitor its effects on physiological measures and a variety of self-reported feelings.
2. Methods
Nineteen subjects were studied, 9 males and 10 females with a mean age of 33 (range = 23-57) all employees of the Institute of Psychiatry. 2.2. Experimentul
situation and design
Each subject was told that he was engaged in a competitive reaction time task with a subject in another room. The subject was instructed to adjust a switch on his task board (fig. 1) at the beginning of each trial so that any of 8 intensities of noise (range = 70-105 dB) could be delivered. These noises, he was informed, would be administered to his opponent at the end of the trial if his reaction time was faster than this opponent’s: his opponent had similar privileges. Thus the subject realised that he might hear or administer a noise depending on the outcome of the competition and the magnitude of the noise could be varied by both competitors. In fact there was no opponent. The level of provocation was increased through the experiment. After the initial (no provocation) trial, the 24 trials were divided into 4 blocks of 6 trials each. On the first block, the noise level averaged 1.5; on the second block, 3.5
111*13141W+l Volume Volume to to other
set
by other
be delivered subject
0 Press
when
0 Set
volume
Fig. 1. Task board.
volume
set
0 Warning
0 Reaction
Timer
subject
and on the third and fourth, 5.5 and 7.5 respectively. actual noise on 50% of occasions within each block.
The subject
heard
the
the same sequence
of
2.3. Procedure All subjects events. (1) Green
received
light on
(2) Green button (3) Light display (4) (5) (6) (7)
25 trials.
on
Amber light on Red light on Red button Noise
Certain
measures
Each trial contained
- signal for subject to set the level of noise for their opponent. - subject presses when ready to proceed. of lights (1-S) was illuminated to - a number display the level of noise set by the opponent. - warning for R.T. stimulus. - R.T. stimulus. _ subject presses in response. _ administered on 50% trials.
were taken from these events:
(a) Setting time was the time taken from the onset of the green light to the subject pressing the green button indicating he has turned the switch onto his chosen setting. (b) Level set was that which the subject set for their opponent to receive on each trial. (c) Reuction time. The visual reaction time was measured in msec. The data from the 25 trials were summarized by a Pre Score (trial 1) and four subsequent scores, each representing the mean of 6 trials. A PDP 12A laboratory computer controlled the events in the experiment, recorded the other variables and administered the noises. 2.4. Physiological
measures
2.4.1. Heart period.The heart period was monitored throughout the experiment. During each trial, mean inter-beat-intervals (IBI) were taken around the significant events - Pre Green Light; Post Ready Button; Post Volume Display; Post Amber Light; Post Noise or No-Noise. These figures were averaged for blocks of 6 trials giving a Pre (trial one) score and 4 other readings. 2.4.2. Skin conductance level and fluctuations. The palmer skin conductance was recorded throughout the experiment on a Grass Polygraph as described previously (Bond and Lader, 1972). Two readings were taken within each trial at the beginning (Pre Green Light) and at the point of greatest change within the trial. The latter was expressed as a difference score from the pre trial level. These 2 scores were averaged across the 4 blocks of trials. The number of
12
Name
A. Bond and M. lader
Age . .
Date
/ A~gress~on elicited by prouocatran
Sex
I. Please rate the way you feel in terms of the dimensions given below 2. Regard the line as representing the full range of each dimension 3. Rate your feelings as they are AT THE MOMENT 4. Mark clearly and perpendicularly across each line ANGRY AFFABLE FURIOUS SOCIABLE AGGRESSIVE BELLIGERENT RESENTFUL PATIENT FRIENDLY SPITEFUL ANNOYED PLEASED REBELLIOUS Fig. 2. Aggression
PEACEFUL QUARRELSOME CALM UNSOCIABLE COOL-HEADED RESTRAINED TOLERANT IMPATIENT HOSTILE BENEVOLENT COMPOSED DISGUSTED COMPLIANT
_ _ _ _ _
_ _ rating
scale.
fluctuations greater than a certain criterion (1% of baseline level) was counted for 15 set at the beginning of the trial before the Green Light (Pre), for 15 see after the ready button (during) and for 15 set after the reaction time was recorded (post). These figures were then averaged across the 4 blocks of trials and divided into Noise and No-Noise conditions. 2.5. Suhjeclive
ratings
2.5.1. Mood Rating Scafe (MRS). The subjects completed a visual analogue mood rating scale of 16 items. For each item the subject had to make a mark along a 100 mm line and the score was measured in mm from the scale end to that mark. In addition 3 factors previously isolated from the scale. were analysed (Bond and Lader, 1974). 2.5.2. Aggression Rating Scale (ARS). This scale consisted of 13 items measuring feelings of hostility and was constructed in a similar way to the MRS (fig. 2). 2.5.3. Spielberger State Anxiety Inventory (SSAI). The SSAI was used with an instruction requiring subjects to indicate how they felt ‘at this moment’, (Spielberger, Gorsuch and Lushene, 1969). All three scales wese completed both before the competitive reaction time task and immediately after it. 2.6. Analysis of data Analysis of variance (sex, time and sex X time) was used to analyse the data for the variables which were measured on the 4 blocks of trials and for the ratings. Linear trends were examined.
A. Bond and M. Lader / Aggressmn
elrcired b?:prmocatwn
13
3. Results Only significant
results are shown.
(1) Setting time. The time taken by the subjects to set the noise level for their (2)
opponent decreased significantly through the experiment (p < 0.002) with a linear trend (p < 0.025). Level set. The level of noise that the subjects set for their opponent significantly increased through the experiment (p < 0.007) with a linear trend ( p < 0.01) (fig. 3).
3. I. Physiological
measures
3.1.1. Heart period: Post ready button. This is a waiting period: the subjects have selected the level of noise for their opponent and are anticipating their opponent’s setting. During this time, the heart period (HP) grew significantly longer through the experiment (p < 0.003) and in a linear fashion (p < 0.005). Post noise or no-noise. There was no significant change after the subjects heard a noise through the experiment i.e. increasing noise levels did not alter
8 7
-
6
-
/ / 5
$4
-
-
: .$3
-
z" 2
-
l-
o
Trial
I
r
1
l-2
I
3-4 L.34
5-6
7-a
received
Fig. 3. Mean level of noise which the subjects administered blocks of trials (0-O) and the level which they received (-
-
to their opponent -).
over successive
A. Bond and M. Lnder / Aggression elrcited b.y prowcutron
14
I a.1
840
Q, \
_
‘1 ‘O-,.__
-0,
\
post \
820
-
no-noise
\
‘0 800
-
780 -
760 -
740
-
+
07,;
, 1
2-7
r
8 -13
14-19
, 20-25
Trials Fig. 4. The mean inter-beat-interval no-noise.
of the heart rate over successive
blocks of trials
post noise and
the subjects’ heart-period (fig. 4). When no noise occurred, the HP showed a progressive shortening over trials (p < 0.05) with a linear trend ( p < 0.06). When the two conditions were compared there was a highly significant difference between them (p < 0.0005) which did not change with increasing noise level. The HP was significantly longer when no noise occurred.
There was a significant difference between sexes on baseline skin conductance level ( p -=z0.02); the males having a higher level (X = 11.1) than the females (X = 7.5). There was no significant interaction of sex with time, both
by prooocution
A. Bond and M. Loder / A.ggre.won rlmted 1.1 -
10
-
0 0
///
0 -0
2.5
-
29
-
75
0,-o \
:
\ .9
.P 3
-
I5
‘0
-
; 3 4
-
IL 5 01
.7
07
1 s
-
5
-
o-
I
1
1.0 -
0 -13
2-7
14 -- 19
20 -25
0
I
!
we
During
Post
Trials
Fig. 5. The mean change in skin conductance level in microsiemens within each trial shown over successive blocks of trials (left). The mean number of fluctuations within trial shown for pre trial, ) and no-noise (- ~ -). during the trial and post noise (-
sexes increasing through the experiment (p < 0.001) with a linear trend (p < 0.006). When the change in SCL within each trial was analysed, the measure altered significantly through the experiment (p < 0.0005) (fig. 5). The difference from baseline increased over the successive blocks of trials i.e. as the noise became louder, and showed a linear trend ( p cc 0.006). Males had significantly more fluctuations both pre trial (p < 0.025) and during the trial (p < 0.005) but not post noise/no-noise. There was no significant interaction effect. There was no significant difference across blocks of trials through the experiment but there was a significant difference within the trials. The number of fluctuations increased from pre trial to the rest of the trial (p < 0.0001). There was also a significant difference between the noise and no-noise conditions ( p < 0.0002), with more fluctuations after the noise (fig. 5). 3.2. Subjective
ratings
There were no sex differences
on any of the rating
scales.
3.2. I. Mood rating scale The only item which showed a significant change on this scale was amicable-antagonistic: the subjects rated themselves as significantly less amicable after the task (p < 0.005). They also tended to show increased excitement and tension as measured by the factor 3 score ( p < 0.06).
76
3.2.2. Aggression
A. Bond and M. Lader / Aggressron elicited by prorocatron
ruting scale
Five items on this scale showed a significant change after the task: affable-quarrelsome ( p < 0.05); calm~furious ( p < 0.04); restrained-belligerent ( p < 0.04). All the other scales showed similar but non-significant changes. 3.2.3. Spielberger
SSA I
There was no significant change after scores were 35.8 (pre) and 39.6 (post).
the task on this scale. The mean
4. Discussion Our results show that the competitive reaction time task used in this experiment succeeded in eliciting hostility which could be measured behaviourally, physiologically and emotionally. The subjects came into the laboratory feeling alert, contented and calm (MRS), generally friendly and peaceful (ARS) and showing mild situational anxiety (SSAI). After the competitive reaction time task their self-assessments of alertness and contentedness did not change, but their interpersonal feelings did. They felt less amicable and friendly and admitted to feelings of hostility on the ARS. They rated themselves as more antagonistic towards the other person but not unhappy in themselves. Their anxiety scores did not change much but they did rate increased excitement and tension as would be expected from a competitive task. The behavioural measure of hostility in this experiment was the level of noise which the subjects set for their ‘opponent’. The subjects increased this setting in response to provocation. The subjects changed physiologically during the experiment. For the heart period, the change in arousal was greatest on the first trial; the HP shortening from 800 msec at the start of the trial to 740 msec after the noise (fig. 6). On subsequent trials, the subjects showed a similar pattern which changed significantly at only two points. After the subjects had set the noise level for their opponent their HP lengthened significantly through the experiment. The difference was small indicating that the variability between subjects was minimal. It occurred at a time of rest or waiting and may reflect the subjects’ anticipation of their opponent’s setting. The heart period after the noise differed from that in the no-noise condition. When no noise occurred, the HP progressively shorterned through the experiment. This is probably a fear reaction as the subjects anticipated receiving louder and louder noises and this proposition is confirmed by the even greater shortening when the noise actually occurred.
A. Bond and M. Lader
/ Aggresston
elrcited
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trials
I.B.I. n 840
by pro~wution
2-7
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820
800
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780
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‘0 \ \
Fig. 6. The mean inter-beat-interval of trials.
O\
0
trial
1
of the heart rate shown for trial 1 and the 4 subsequent
blocks
That males have significantly higher skin conductance levels than females has been reported before (Ward, Doerr and Storrie, 1983) but may simply reflect the sex of the experimenter, in this case female (Gale and Baker, 1981). Both sexes showed a significant increase in level through the experiment suggesting that the subjects were becoming more aroused physiologically through the experiment with no evidence of habituation. This was confirmed by the difference score in level which was measured on each trial and which also increased with mounting provocation. The number of fluctuations did not increase through the experiment but it did increase within each trial. The
subjects relaxed between trials (pre or resting measure) but arousal increased with the sequence of events and again the number of fluctuations was greater after the noise than when no noise occurred. Thus the actual noise increased heart rate, skin conductance level and fluctuations, confirming that it was a potent noxious stimulus. Our findings are similar to those found previously using shocks. We used the conditions which have been found maximal in producing socially mediated aggression e.g. increasing levels of provocation, equai ability as evidenced from a 50% defeat ratio (Epstein and Taylor, 1967), and found these conditions to elicit hostility following noises in a similar way to that found by the previous authors using shocks. This device therefore proved very useful in eliciting hostility. The subjects showed increased anger on behavioural, physiological and self-rating measures. The mood effects were inter-personal, directed outward and were not directed inward either in the form of sadness or anxiety. This lack of reported anxiety suggests that the arousal shown on the skin conductance measures is a concomitant of anger rather than fear or anxiety with the exception of the stress response to the actual noise. Interestingly the subjects experienced these feelings even though some of them suspected that there was no other person. It is possible that these subjects, who became sceptical during the experiment, directed their anger at the experimenter or perhaps in this automated age of computers, ‘space-invaders’ and the like, competing against a machine arouses as much aggression and frustration as competing against another human being.
References Bandura, A. (1973). Aggression. A Social Learning Analysis. Prentice-Hall: New Jersey. Bond, A.J. and Lader, M.H. (1972). Residual effects of hypnotics. Psychopharmacologia (Berl.). 25, 117-132. Bond. A.J. and Lader, M.H. (1974). The use of analogue scales in rating subjective feelings. British Journal of Medical Psychology, 47, 211-218. Edmunds, G. and Kendrick. D.C. (1980). The measurement of human aggressiveness. Wiley: New York; Ellis Horwood Ltd: Chichester. Epstein, S. and Taylor, S.P. (1967). Instigation to aggression as a function of degree of defeat and perceived aggressive intent of the opponent. Journal of Personality, 35, 265-289. Gale, A. and Baker, S. (1981). In Vivo or In Vitro? Some effects of Laboratory environments, with particular reference to the psychophysiology experiment. In: Christie, M.J. and Mellett, P. (Eds). Foundations of Psychosomatics. John Wiley and Sons Ltd: Chichester, 363-384. Geen, R.G. (1976). Personality. the Skein of Behaviour. Henry Kimpton. Hinde. R.A. (1974). Biological Bases of Human Social Behaviour. McGraw-Hill: New York. Lundberg, U. and Frankenhaeuser, M. (1978). Psychophysiological reactions to noise as modified by personal control over noise intensity. Biological Psychology, 6. 51-59. Spielberger, C.D., Gorsuch, R.L. and Lushene, R.E. (1969). The State-Trait Anxiety Inventory. Palo Alto, CA: Consulting Psychologists Press.
A. Bond md h4. Lader
Taylor, S.P. (1967). Aggressive and the tendency to inhibit Taylor, S.P. and Epstein. S. Medicine. 29. 514-525. Ward. N.G.. Doerr. H.O. and for depression. Psychiatry
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behaviour and physiological arousal as a function aggression. Journal of Personality. 35, 297-310. (1967). The measurement of autonomic arousal. Storrie, M.C. (1983). Skin conductance: Research. 10. 295-302.
A potentially
of provocation Psychosomatic sensitive
test