British Journal of Social and Clinical Psychology (1979). 18, 13-19
Printed in Great Britain
13
Orienting responses and locus of control Tim Lobstein, Bob Webb and Otto Edholm Few studies have attempted to relate the locus of control (Rotter, 1966) variable to physiological activity. This paper describes the heart-rate and skin conductance responses of 40 subjects exposed to a series of auditory stimuli, in relation to their locus of control scores. It was found that those scoring relatively
‘externally’ on the locus of control scale gave less decelerative and more accelerative heart-rate responses and tended to give larger skin conductance responses when there was a change in stimulus characteristics,than those scoring ‘internally’. These results may be interpreted to support Lazarus’ (1966) suggestions that control over a situation lessens the threat perceived in that situation. They also indicate that internal subjects tend to seek information to increase their control. The locus of control scale, derived from Rotter’s (1954, 1966) social learning theory, assesses the degree to which ‘individuals perceive the events in their life as being a consequence of their own actions and thereby controllable (internal control), or as being unrelated to their own behaviours and therefore beyond personal control (external control)’ (Lefcourt, 1972, p. 2). Subjects with different locus of control scores appear to differ in a number of ways (see also Joe, 1971) including reaction to threat; hostility and emotional lability; response to psychotherapy; and in their self-esteem and self-control. Generally, subjects with expectations of external control tend to react with increased hostility, make less effective coping responses and have lowered self-esteem compared with internal subjects. Lazarus (1966) has suggested that subjects who specifically or generally believe they have control over the environment should perceive less threat (and thus be less anxious) in a threatening situation than subjects who tend to believe they are helpless. In the specific sense, Glass & Singer (1972), Staub et al. (1974) and others, have shown subjects to be less anxious and less aroused when aversive stimuli were controllable or predictable than when they were not. In the general sense, ascertained by the locus of control scale, we might expect internally scoring subjects to show less anxiety in response to an arousing stimulus than externally scoring subjects. The present paper examines the relationship between orienting responses to a series of non-signal tones and the locus of control variable. The orienting, or alerting response is a pattern of physiological changes that occurs when a subject perceives a stimulus, of which an increase in palmar sweating and a biphasic heart-rate response (Graham & Clifton, 1966) are commonly a part. Responses can habituate with repeated presentations of the same stimulus, and may reappear if the stimulus alters. In the present report, the stimuli are meaningless tones, and do not signal any required overt response from the subject. Studies of individual differences in responses to such stimuli suggest that slower habituation may be related to neuroticism (Coles et al. 1971; but see, Sadler et al. 1971, for contradictory data). The locus of control variable has not previously been examined in terms of physiological orienting responses. Data relating to the first response of a series need to be interpreted with caution; Lader & Wing (1%6), e.g. state that they put little emphasis on the first response as it was found to be highly variable. The experiment reported here was designed with a second series of tones of lower pitch presented immediately after the first series. An unexpected change in stimulus characteristics of this sort, which contradicts an expected pattern and possibly heralds a significant change in the environment, may elicit differential responses from internal and external subjects. Following Lazarus, internal subjects might be expected to show less anxiety-like responding (palmar sweating, heart-rate increase) than external subjects. 0007-1293/79/0201-0013$02.00/0 (01979 The British Psychological Society
14
Tim Lobstein. Bob Webb and Otto Edholm
Method Procedure Forty subjects, 20 of each sex, mean age 21.9 years (SD 5.7), were drawn from a college population on a voluntary, nominally paid basis. Time of day of testing was counterbalanced across subjects (10-12 a.m., 2-5 p.m.1. Each subject was asked not to eat, or drink other than water, for an hour prior to the experiment. No subject had been to the laboratory before. On arrival they were given 20 min acclimatization to the environment during which time they completed the locus of control scale (Norwicki & Duke, 1974) or the Eysenck Personality Inventory (half the subjects completed the EPI or the locus of control scale after the end of the session). Subjects sat in a comfortable chair in a small, temperature controlled (2021 “C), sound attenuated (mean extraneous noise level approximately 40 dBA) cubicle with reduced lighting (50 lux red light from a 15 watt bulb). Electrodes were attached and the subjects instructed as follows: ‘This part of the experiment is about relaxation. Please just sit here and relax but keep awake. You will hear occasional “pips” through these headphones but these don’t mean anything, so just ignore them. In about 20 minutes we’ll go on to the next bit of the experiment. OK?’ If necessary, subjects were reassured that there was nothing unpleasant about the tones or any other aspect of the experiment. They were not told that the tones would alter in pitch. Headphones were put in place and the experimenter left the cubicle, closed the door and calibrated the polygraph. All subjects then received the following schedule: a 2 min quiet period followed by a series of 15 tones (1 s duration, rise and fall times of 25 ms, 85 dBA, lo00 Hz, at pseudo-random intervals 25-50 s, mean 35 s. These tones were immediately followed by a second series of three tones, which continued with identical characteristics as the first series of tones, with the exception that the pitch of each tone was 500 Hz. There followed a second period of 2 min silence. Subjects were then released from the electrodes and asked to complete the second personality questionnaire.
Apparatus Following Venables & Christie’s recommendations (l973), bipolar skin conductance was recorded from the medial phalanges of the first and second fingers of both hands using AglAgCl 1 cm* electrodes, 5 per cent KCI agar-agar electrolyte, and the recommended constant voltage circuit (approximately 0.5 V). ECG was recorded from the forearms (Standard lead I) using Cambridge electrodes and electrolyte. Data were recorded on a Grass 7 polygraph. Stimuli were presented through Sansui SS2 headphones, from a Bruel and Kjoer signal generator through a Grason Stadler electronic switch (1212) and Leak 30 amplifier. Decibel levels were measured through a B and K sound level meter and artificial ear (headphone adaptor).
Scoring Heart rate was scored from the cardiotachometer record, sensitive to one beat per minute. Heart-rate responses were derived from the post-stimulus beats expressed as deviations from the mean value of the 10 pre-stimulus beats, and are defined as the minimum value in beats one to five post-stimulus (deceleration) and maximum value in beats one to six (acceleration), both scores expressed as deviations from the pre-stimulus mean value. These response features are similar to those described by Koriat et al. (1973), and to the D, and A scores used by Bull & Lang (l972), and generally account for the biphasic cardiac response usually found after a brief orienting stimulus. Heart-rate levels are those derived from the mean of the ten beat sequences prior to the first and the 16th stimulus. Heart-rate variability is the range shown (maximum minus minimum) in the first 10 beat sequence. Skin conductance responses were defined as transient increases in level starting between 1 and 5 s after stimulus onset, greater than 0.02 micromhos. Latency and recovery half-time are defined by Venables & Christie (1973) and are essentially the time from stimulus onset to response onset, and time from the response peak to a half-amplitude return. Trials to habituation is defined as the number of stimuli before habituation takes place, i.e. the last stimulus on which a response occurs (followed by the end of the series or three consecutive non-responding trials). This habituation measure is commonly found in the literature and is usually free of initial value effects. Unfortunately there is no equivalent for cardiac responses due to the difficulty in defining when no response has occurred. Skin conductance tonic levels were averaged from the minute immediately before the first stimulus and the minute before the end of the recording schedule, and the number of spontaneous fluctuations taken from the minute before the first stimulus.
Orienting responses and locus of control
15
Results Mean score on the locus of control scales was 11.55 (SD 4.5 1) and males and females showed no significant difference (males 11.65, females 11.45). Correlations between locus of control and extraversion ( r = -0.14) and neuroticism ( r = 0.03) were not significant. Locus of control and neuroticism showed an interaction in the measures of heart-rate response to the reorienting stimulus (see below). Apart from this the locus of control and EPI variables showed little interaction on the physiological measures. Two groups of subjects were defined: those scoring above the median were called external (mean score 15.25, SD 2.97) and those below called internals (mean score 7.85, SD 2.01), divided to allow equal numbers of each sex in each group. However, scores on the locus of control scale tend to be distributed normally, which argues against the use of a simple typological division. For this reason appraisal of the relationship between locus of control and the physiological measures takes two forms: analysis of variance for a measure across the internal-external classification (and across gender), and product moment correlations (see Table 1). Where gender is a significant factor, or interacts with locus of control, this is indicated in the text. Table 1. Locus of control and physiological measures: Analyses of variance and correlations. Means and standard errors for the two personality subgroups are indicated, and the significance level for the resulting analysis of variance (which included gender). Pearson correlation coefficients are given, and their associated significance levels Internals
N
Externals
p ( F ) onetailed r
X
s.e.
x
s.e.
-8.09
4.18 -7.93 2.25 t 3.66 +2*58 67.70 +0*02
I .39 0.93 0.80 0.84 1*80 1.61 243 0.76
-3.39 5.77 -4.70 5.53 -0.88 -0.59 68.14 -0.58
1.17 1.36 0.63 0.91 I .44 1.31 2.28 0.85
< 0.01 n.s. < 0.005 < 0.005 < 0.05 n.s. n.s.
12.05
1.67
10.95
2.32 2.43 0.77 0.47 8.% 5 *67 5.57 -0.79
0.21 0.22 0.17 1.16 1.93 0.68 0.37
242 2.10 0.75 1.05 10.19
1.4 3.8
R r)
Heart rate t. I deceleration 40 t. 1 acceleration 40 t. 16 decelaration 40 t. 16 acceleration 40 t. 15-t. 1 deceleration 40 t. 154. 1 acceleration 40 Mean level, pre-t. I 40 Mean level change 40 pre-t. 16-pre-t. 1 Range, pre-t. I 40 Skin conductance Latency t. 1 28 Latency 1. 16 13 Amplitude t. 1 28 Amplitude t. 16 13 Recovery half-time t. I 26 Recovery half-time t. 16 13 Tonic level, minute pre 40 Tonic level change, 40 minute post-minute pre Spontaneous fluctuations, 40 minute pre Trials to habituation 40
ns.
-0.20 0.0 1 -0.33 0.23 -0.19 -0.38 0.00 0.13
n.s. n.s. < 0.025 < 0.10 n.s. < 0.01 ns. n.s.
1.16
n.s.
-0.03
n.s.
ns.
5.3 I -0.59
0.26 0.1 1 0.2 1 0.36 I .45 1.98 0.69 0.3 I
ns. ns.
0.12 -0.46 0.13 0.54 0.02 0.31 0.06 0.12
n.s. < 0.10 n.s. < 0.05 n.s. n.s. n.s. n.s.
0.6
0.6
0.3
n.s.
-0.06
ns.
1 .o
3. I
I .o
ns.
0.15
n.s.
0.15
11.58
< 0.10 ns.
< 0.10 n.s. < 0.05
16
Tim Lobstein, Bob Webb and Otto Edholm Stimulus I
Q
c
.-3 C E L n Q. c) Y)
d
t
:
1
2
;
;
:
i
:
i
:
:
i
l
3 4 5 6 7 8 9 1 0 1 1 I ? Post-stimulus consecutive cardiac cycles Stimulus I6
/x - I
Figure 1. Change in heart rate from pre-stimulus mean level for internally scoring ( 0 4 ) and externally scoring (x-x) subjects. The former group tend to show more heart-rate fall and less rise compared with the latter group, particularly to the reorienting stimulus (number 16).
Heart rate
The major finding is that external subjects show less deceleration and more acceleration in response to a reorienting stimulus (stimulus 16) than do internal subjects. The same relationship tends to apply to stimulus I , the first tone heard. An interaction with neuroticism suggested that internal, stable (low neuroticism score) subjects show the most initial deceleration and least early acceleration, and external stable subjects the least deceleration and most acceleration, i.e. the relationship between locus of control and heart-rate responding appears to apply most strongly among the subjects scoring towards the non-neurotic end of the neuroticism scale. With respect to the law of initial values, the correlations between the mean initial heart rate and the other heart-rate variables never approach significance. The range score correlates with stimulus one acceleration ( r = 0.42, P < and stimulus 16 deceleration ( r = 0.39, P < 0.01) and acceleration ( r = 0.34, P < 0.025). Partialling out this range factor does not significantly reduce the relationship between locus of control and any of these measures, and indeed strengthens that between locus of control and stimulus 16 deceleration ( r = 0.37, P < 0.01). The relationship of the change in response scores between the first and 15th stimuli with locus of control suggests that the deceleration shown by internals to the first trial habituates. The change in the mean pre-stimulus heart-rate levels across the same period correlates significantly with the change in deceleration ( r = 0.49, P < 0.01) where a fall in heart-rate level is associated with a reduced decelerative response. Change in heart-rate level is not correlated with a decline in the accelerative response ( r = -0.14). O e O I ) ,
Orienting responses and locus of control
17
Skin conductance
Twelve of the 40 subjects showed no response to the first stimulus, and an additional 15 subjects gave no response to the reorienting stimulus (stimulus 16). The proportion of first stimulus ‘non-responders’ was the same among internals as externals, and did not significantly differentiate males from females. The proportion of stimulus 16 non-responders did not differentiate internals from externals but non-responding was more common among women than men (xz = 4-10, P < 0.05). One reason for the large number of skin conductance non-responders may have been the relatively low laboratory temperature in conjunction with the cold weather (Jan.-Feb. 1975) to which some subjects were exposed. Venables & Martin (1967) suggest that longer response 0.50
X
0.40
3
r.
E
e f 0
0.30
0.20
0.10
Stimuli
Figure 2. Mean amplitude of non-zero skin conductance responses for internally scoring (04) and externally scoring ( x - x ) subjects. The former group tend to show smaller reorienting responses to the 16th stimulus than do the latter group.
latencies may be associated with low skin temperatures, and in the present experiment those responding to stimulus 1 but not to stimulus 16 gave longer latencies to stimulus 1 than those who responded to both stimuli (means 2.89 and 2.20 s, t = 2.22. P < 0.05). Despite the low number of subjects responding to the 16th stimulus, the results support the heart-rate data. Amplitudes of non-zero responses are smaller, latencies tend to be longer and recovery times are faster for internals compared with externals. Women tended to show fewer trials to habituation than men ( p ( F )< 0.10) and showed fewer spontaneous responses (p(F)< 0.05). Discussion The results are consistent with the suggestions made in the introduction, that subjects scoring more externally would tend to show greater heart-rate and sweat-rate increases to unexpected stimuli than would internally scoring subjects. A distinction should be made, however, between the conditions described in this experiment, where subjects sat passively and received tones with little signal value and situations where subjects may be required to perform some task or make
18
Tim Lobstein, Bob Webb and Otto Edholm
other overt responses. In the latter situation motivational variables may elicit raised heart-rate and palmar sweating levels. Motivation appears to be generally higher among subjects scoring internally, particularly that associated with avoidance of failure (McGhee & Crandall, 1%8). Thus the raised heart rate found among internal subjects compared with external by Bennett et al. (1977) in a tracking task situation, and by Houston (1972) in a memory task with noxious penalties, may derive from motivational factors largely excluded in the present study. Heart-rate deceleration in the orienting response may reflect information factors (Graham & Clifton, 1966). The data presented here, showing internals giving greater decelerative responses, support Davis & Phares’ (1967) suggestion that internals tend to seek information. The correlation between deceleration and acceleration scores following stimulus 16 was not significant ( r = 0.23), and thus information-seeking responses may be independent of the arousal response. Skin conductance recovery time may relate to information intake and defensive aspects of a situation (Edelberg, 1972; Furedy, 1972); longer recovery time being associated with more noxious stimuli and shorter times with an attentional task. Following stimulus 16 externals gave longer recovery times than internals. Moreover, recovery time relates to heart-rate deceleration and acceleration amplitudes appropriately on stimulus 16 ( r = -0.77, P < 0.01 and r = 0.68. P < 0.05 respectively), although not significantly following stimulus one. From the evidence presented here it appears that a reorienting response, elicited by a small change in an otherwise predictable event, may reveal attentional and arousing components of a situation. These in turn relate to the individual’s generalized attitude about his or her ability to influence the environment (locus of control). Acknowledgements We are indebted to Karen McGrath for her assistance in the preparation of this paper. The work was supported by a Medical Research project grant to Professor R. G. Hopkinson, to whom we are also indebted.
References BENNETT, M. D., WEBB,R. & WITHEY,W. R. (1977). Personality, performance and physiological cost during vibration. Journal of Physiology (in press). BULL, K. & LANG,P. J. (1972). Intensity judgements and physiological response amplitude. Psychophysiology, 9, 428-436. COLES.M. G. H., GALE,A. & KLINE. P. (1971). Personality and habituation of the orienting reaction: Tonic and response measures of electrodermal activity. Psychophysiology, 8, 54-63.
W. L. & PHARES, E. J. (1%7). DAVIES, Internakxternal control as a determinant of information-seeking in a social influence situation. Journal of Personality, 35. 547-561. EDELBERG, R. (1972). Electrodermal recovery rate, goal-orientation, and aversion. Psychophysiology. 9.512-520.
FUREDY, J . J. (1972). Electrodermal recovery time as a supra-sensitive autonomic index of anticipated intensity of threatened shock. Psychophysiology, 9, 28 1-282. GLASS,D. C. & SINOER. J. E. (1972). Urban Stress: Experiments on Noise and Social Stressors. New York: Academic Press. GRAHAM, F. K. & CLIITON,R. K. (1966). Heart
rate change as a component of the orienting response. Psychological Bulletin, 65, 305-320. HOUSTON, B. K. (1972). Control over stress, locus of control, and response to stress. Journal of Personality and Social Psychology. 21, 249-255. JOE, V. C. (1971). Review of the internakxternal control construct as a personality variable. Psychological Reporfs, 28. 619440. E. J. KORIAT,A., AVERILL, J. R. & MALMSTROM, (1973). Individual differences in habituation; some methodological and conceptual issues. Journal of Research in Personality, 7. 88-101. LADER,M. H. &WING,L. (1966). Physiological Measures, Sedative Drugs and Morbid Anxiety. London: Oxford University Press. LAZARUS, R. S. (1966). Psychological Stress and the Coping Process. New York: McGraw-Hill. LEFCOURT, H.M. (1972). Recent developments in the study of locus of control. I n B. Maher (ed.), Progress in Experimental Personality Research, vol. 6 . New York: Academic Press. MCGHEE, P. E. & CRANDALL, V. C. (1968). Beliefs in internalexternal control of reinforcement and academic performance. Child Developmenf, 39, 9 1- 102. S . & DUKE,M. P. (1974). A locus of NOWICKI, control scale for non-college as well as college
Orienting responses and locus of control adults. Journal of Personalify Assessment, 38. 136137. ROTTER,J. B. (1954). Social Learning and Clinical Psychology. New York: Prentice-Hall. ROTTER, 3. B. (1966). Generalised expectancies for internal versus external control of reinforcement. Psychological Monographs, 80, whole no. 609. SADLER, T. G., MEFFERD, R. B. & HOUCK,R. L. (1971). The interaction of extraversion and neuroticism in orienting response. Psychophysiology, 8. 312-318.
19
STAUB,E., TURSKY, B. & SCHWARTZ. G. E. (1971). Self-control and predictability: Their effects on reactions to aversive stimulation. Journal of Personality afid Social Psychology, 18, 157-162. P. H.& CHRISTIE,M. J. (1973). VENABLES, Mechanisms, instrumentation, techniques and quantification of responses. In W. F. Prokasy & D. C. Raskin (eds), Electrodermal Activity in Psychological Research. New York: Academic Press.
Received 30 March 1977; revised version received 10 June 1977 Requests for reprints should be addressed to Dr T. J. Lobstein. School of Environmental Studies, University College London, Gower Street, London WClE 6BT. Otto Edholm is at the same address. Bob Webb is now at Toronto University.
Printed in Great Britain
13
Orienting responses and locus of control Tim Lobstein, Bob Webb and Otto Edholm Few studies have attempted to relate the locus of control (Rotter, 1966) variable to physiological activity. This paper describes the heart-rate and skin conductance responses of 40 subjects exposed to a series of auditory stimuli, in relation to their locus of control scores. It was found that those scoring relatively
‘externally’ on the locus of control scale gave less decelerative and more accelerative heart-rate responses and tended to give larger skin conductance responses when there was a change in stimulus characteristics,than those scoring ‘internally’. These results may be interpreted to support Lazarus’ (1966) suggestions that control over a situation lessens the threat perceived in that situation. They also indicate that internal subjects tend to seek information to increase their control. The locus of control scale, derived from Rotter’s (1954, 1966) social learning theory, assesses the degree to which ‘individuals perceive the events in their life as being a consequence of their own actions and thereby controllable (internal control), or as being unrelated to their own behaviours and therefore beyond personal control (external control)’ (Lefcourt, 1972, p. 2). Subjects with different locus of control scores appear to differ in a number of ways (see also Joe, 1971) including reaction to threat; hostility and emotional lability; response to psychotherapy; and in their self-esteem and self-control. Generally, subjects with expectations of external control tend to react with increased hostility, make less effective coping responses and have lowered self-esteem compared with internal subjects. Lazarus (1966) has suggested that subjects who specifically or generally believe they have control over the environment should perceive less threat (and thus be less anxious) in a threatening situation than subjects who tend to believe they are helpless. In the specific sense, Glass & Singer (1972), Staub et al. (1974) and others, have shown subjects to be less anxious and less aroused when aversive stimuli were controllable or predictable than when they were not. In the general sense, ascertained by the locus of control scale, we might expect internally scoring subjects to show less anxiety in response to an arousing stimulus than externally scoring subjects. The present paper examines the relationship between orienting responses to a series of non-signal tones and the locus of control variable. The orienting, or alerting response is a pattern of physiological changes that occurs when a subject perceives a stimulus, of which an increase in palmar sweating and a biphasic heart-rate response (Graham & Clifton, 1966) are commonly a part. Responses can habituate with repeated presentations of the same stimulus, and may reappear if the stimulus alters. In the present report, the stimuli are meaningless tones, and do not signal any required overt response from the subject. Studies of individual differences in responses to such stimuli suggest that slower habituation may be related to neuroticism (Coles et al. 1971; but see, Sadler et al. 1971, for contradictory data). The locus of control variable has not previously been examined in terms of physiological orienting responses. Data relating to the first response of a series need to be interpreted with caution; Lader & Wing (1%6), e.g. state that they put little emphasis on the first response as it was found to be highly variable. The experiment reported here was designed with a second series of tones of lower pitch presented immediately after the first series. An unexpected change in stimulus characteristics of this sort, which contradicts an expected pattern and possibly heralds a significant change in the environment, may elicit differential responses from internal and external subjects. Following Lazarus, internal subjects might be expected to show less anxiety-like responding (palmar sweating, heart-rate increase) than external subjects. 0007-1293/79/0201-0013$02.00/0 (01979 The British Psychological Society
14
Tim Lobstein. Bob Webb and Otto Edholm
Method Procedure Forty subjects, 20 of each sex, mean age 21.9 years (SD 5.7), were drawn from a college population on a voluntary, nominally paid basis. Time of day of testing was counterbalanced across subjects (10-12 a.m., 2-5 p.m.1. Each subject was asked not to eat, or drink other than water, for an hour prior to the experiment. No subject had been to the laboratory before. On arrival they were given 20 min acclimatization to the environment during which time they completed the locus of control scale (Norwicki & Duke, 1974) or the Eysenck Personality Inventory (half the subjects completed the EPI or the locus of control scale after the end of the session). Subjects sat in a comfortable chair in a small, temperature controlled (2021 “C), sound attenuated (mean extraneous noise level approximately 40 dBA) cubicle with reduced lighting (50 lux red light from a 15 watt bulb). Electrodes were attached and the subjects instructed as follows: ‘This part of the experiment is about relaxation. Please just sit here and relax but keep awake. You will hear occasional “pips” through these headphones but these don’t mean anything, so just ignore them. In about 20 minutes we’ll go on to the next bit of the experiment. OK?’ If necessary, subjects were reassured that there was nothing unpleasant about the tones or any other aspect of the experiment. They were not told that the tones would alter in pitch. Headphones were put in place and the experimenter left the cubicle, closed the door and calibrated the polygraph. All subjects then received the following schedule: a 2 min quiet period followed by a series of 15 tones (1 s duration, rise and fall times of 25 ms, 85 dBA, lo00 Hz, at pseudo-random intervals 25-50 s, mean 35 s. These tones were immediately followed by a second series of three tones, which continued with identical characteristics as the first series of tones, with the exception that the pitch of each tone was 500 Hz. There followed a second period of 2 min silence. Subjects were then released from the electrodes and asked to complete the second personality questionnaire.
Apparatus Following Venables & Christie’s recommendations (l973), bipolar skin conductance was recorded from the medial phalanges of the first and second fingers of both hands using AglAgCl 1 cm* electrodes, 5 per cent KCI agar-agar electrolyte, and the recommended constant voltage circuit (approximately 0.5 V). ECG was recorded from the forearms (Standard lead I) using Cambridge electrodes and electrolyte. Data were recorded on a Grass 7 polygraph. Stimuli were presented through Sansui SS2 headphones, from a Bruel and Kjoer signal generator through a Grason Stadler electronic switch (1212) and Leak 30 amplifier. Decibel levels were measured through a B and K sound level meter and artificial ear (headphone adaptor).
Scoring Heart rate was scored from the cardiotachometer record, sensitive to one beat per minute. Heart-rate responses were derived from the post-stimulus beats expressed as deviations from the mean value of the 10 pre-stimulus beats, and are defined as the minimum value in beats one to five post-stimulus (deceleration) and maximum value in beats one to six (acceleration), both scores expressed as deviations from the pre-stimulus mean value. These response features are similar to those described by Koriat et al. (1973), and to the D, and A scores used by Bull & Lang (l972), and generally account for the biphasic cardiac response usually found after a brief orienting stimulus. Heart-rate levels are those derived from the mean of the ten beat sequences prior to the first and the 16th stimulus. Heart-rate variability is the range shown (maximum minus minimum) in the first 10 beat sequence. Skin conductance responses were defined as transient increases in level starting between 1 and 5 s after stimulus onset, greater than 0.02 micromhos. Latency and recovery half-time are defined by Venables & Christie (1973) and are essentially the time from stimulus onset to response onset, and time from the response peak to a half-amplitude return. Trials to habituation is defined as the number of stimuli before habituation takes place, i.e. the last stimulus on which a response occurs (followed by the end of the series or three consecutive non-responding trials). This habituation measure is commonly found in the literature and is usually free of initial value effects. Unfortunately there is no equivalent for cardiac responses due to the difficulty in defining when no response has occurred. Skin conductance tonic levels were averaged from the minute immediately before the first stimulus and the minute before the end of the recording schedule, and the number of spontaneous fluctuations taken from the minute before the first stimulus.
Orienting responses and locus of control
15
Results Mean score on the locus of control scales was 11.55 (SD 4.5 1) and males and females showed no significant difference (males 11.65, females 11.45). Correlations between locus of control and extraversion ( r = -0.14) and neuroticism ( r = 0.03) were not significant. Locus of control and neuroticism showed an interaction in the measures of heart-rate response to the reorienting stimulus (see below). Apart from this the locus of control and EPI variables showed little interaction on the physiological measures. Two groups of subjects were defined: those scoring above the median were called external (mean score 15.25, SD 2.97) and those below called internals (mean score 7.85, SD 2.01), divided to allow equal numbers of each sex in each group. However, scores on the locus of control scale tend to be distributed normally, which argues against the use of a simple typological division. For this reason appraisal of the relationship between locus of control and the physiological measures takes two forms: analysis of variance for a measure across the internal-external classification (and across gender), and product moment correlations (see Table 1). Where gender is a significant factor, or interacts with locus of control, this is indicated in the text. Table 1. Locus of control and physiological measures: Analyses of variance and correlations. Means and standard errors for the two personality subgroups are indicated, and the significance level for the resulting analysis of variance (which included gender). Pearson correlation coefficients are given, and their associated significance levels Internals
N
Externals
p ( F ) onetailed r
X
s.e.
x
s.e.
-8.09
4.18 -7.93 2.25 t 3.66 +2*58 67.70 +0*02
I .39 0.93 0.80 0.84 1*80 1.61 243 0.76
-3.39 5.77 -4.70 5.53 -0.88 -0.59 68.14 -0.58
1.17 1.36 0.63 0.91 I .44 1.31 2.28 0.85
< 0.01 n.s. < 0.005 < 0.005 < 0.05 n.s. n.s.
12.05
1.67
10.95
2.32 2.43 0.77 0.47 8.% 5 *67 5.57 -0.79
0.21 0.22 0.17 1.16 1.93 0.68 0.37
242 2.10 0.75 1.05 10.19
1.4 3.8
R r)
Heart rate t. I deceleration 40 t. 1 acceleration 40 t. 16 decelaration 40 t. 16 acceleration 40 t. 15-t. 1 deceleration 40 t. 154. 1 acceleration 40 Mean level, pre-t. I 40 Mean level change 40 pre-t. 16-pre-t. 1 Range, pre-t. I 40 Skin conductance Latency t. 1 28 Latency 1. 16 13 Amplitude t. 1 28 Amplitude t. 16 13 Recovery half-time t. I 26 Recovery half-time t. 16 13 Tonic level, minute pre 40 Tonic level change, 40 minute post-minute pre Spontaneous fluctuations, 40 minute pre Trials to habituation 40
ns.
-0.20 0.0 1 -0.33 0.23 -0.19 -0.38 0.00 0.13
n.s. n.s. < 0.025 < 0.10 n.s. < 0.01 ns. n.s.
1.16
n.s.
-0.03
n.s.
ns.
5.3 I -0.59
0.26 0.1 1 0.2 1 0.36 I .45 1.98 0.69 0.3 I
ns. ns.
0.12 -0.46 0.13 0.54 0.02 0.31 0.06 0.12
n.s. < 0.10 n.s. < 0.05 n.s. n.s. n.s. n.s.
0.6
0.6
0.3
n.s.
-0.06
ns.
1 .o
3. I
I .o
ns.
0.15
n.s.
0.15
11.58
< 0.10 ns.
< 0.10 n.s. < 0.05
16
Tim Lobstein, Bob Webb and Otto Edholm Stimulus I
Q
c
.-3 C E L n Q. c) Y)
d
t
:
1
2
;
;
:
i
:
i
:
:
i
l
3 4 5 6 7 8 9 1 0 1 1 I ? Post-stimulus consecutive cardiac cycles Stimulus I6
/x - I
Figure 1. Change in heart rate from pre-stimulus mean level for internally scoring ( 0 4 ) and externally scoring (x-x) subjects. The former group tend to show more heart-rate fall and less rise compared with the latter group, particularly to the reorienting stimulus (number 16).
Heart rate
The major finding is that external subjects show less deceleration and more acceleration in response to a reorienting stimulus (stimulus 16) than do internal subjects. The same relationship tends to apply to stimulus I , the first tone heard. An interaction with neuroticism suggested that internal, stable (low neuroticism score) subjects show the most initial deceleration and least early acceleration, and external stable subjects the least deceleration and most acceleration, i.e. the relationship between locus of control and heart-rate responding appears to apply most strongly among the subjects scoring towards the non-neurotic end of the neuroticism scale. With respect to the law of initial values, the correlations between the mean initial heart rate and the other heart-rate variables never approach significance. The range score correlates with stimulus one acceleration ( r = 0.42, P < and stimulus 16 deceleration ( r = 0.39, P < 0.01) and acceleration ( r = 0.34, P < 0.025). Partialling out this range factor does not significantly reduce the relationship between locus of control and any of these measures, and indeed strengthens that between locus of control and stimulus 16 deceleration ( r = 0.37, P < 0.01). The relationship of the change in response scores between the first and 15th stimuli with locus of control suggests that the deceleration shown by internals to the first trial habituates. The change in the mean pre-stimulus heart-rate levels across the same period correlates significantly with the change in deceleration ( r = 0.49, P < 0.01) where a fall in heart-rate level is associated with a reduced decelerative response. Change in heart-rate level is not correlated with a decline in the accelerative response ( r = -0.14). O e O I ) ,
Orienting responses and locus of control
17
Skin conductance
Twelve of the 40 subjects showed no response to the first stimulus, and an additional 15 subjects gave no response to the reorienting stimulus (stimulus 16). The proportion of first stimulus ‘non-responders’ was the same among internals as externals, and did not significantly differentiate males from females. The proportion of stimulus 16 non-responders did not differentiate internals from externals but non-responding was more common among women than men (xz = 4-10, P < 0.05). One reason for the large number of skin conductance non-responders may have been the relatively low laboratory temperature in conjunction with the cold weather (Jan.-Feb. 1975) to which some subjects were exposed. Venables & Martin (1967) suggest that longer response 0.50
X
0.40
3
r.
E
e f 0
0.30
0.20
0.10
Stimuli
Figure 2. Mean amplitude of non-zero skin conductance responses for internally scoring (04) and externally scoring ( x - x ) subjects. The former group tend to show smaller reorienting responses to the 16th stimulus than do the latter group.
latencies may be associated with low skin temperatures, and in the present experiment those responding to stimulus 1 but not to stimulus 16 gave longer latencies to stimulus 1 than those who responded to both stimuli (means 2.89 and 2.20 s, t = 2.22. P < 0.05). Despite the low number of subjects responding to the 16th stimulus, the results support the heart-rate data. Amplitudes of non-zero responses are smaller, latencies tend to be longer and recovery times are faster for internals compared with externals. Women tended to show fewer trials to habituation than men ( p ( F )< 0.10) and showed fewer spontaneous responses (p(F)< 0.05). Discussion The results are consistent with the suggestions made in the introduction, that subjects scoring more externally would tend to show greater heart-rate and sweat-rate increases to unexpected stimuli than would internally scoring subjects. A distinction should be made, however, between the conditions described in this experiment, where subjects sat passively and received tones with little signal value and situations where subjects may be required to perform some task or make
18
Tim Lobstein, Bob Webb and Otto Edholm
other overt responses. In the latter situation motivational variables may elicit raised heart-rate and palmar sweating levels. Motivation appears to be generally higher among subjects scoring internally, particularly that associated with avoidance of failure (McGhee & Crandall, 1%8). Thus the raised heart rate found among internal subjects compared with external by Bennett et al. (1977) in a tracking task situation, and by Houston (1972) in a memory task with noxious penalties, may derive from motivational factors largely excluded in the present study. Heart-rate deceleration in the orienting response may reflect information factors (Graham & Clifton, 1966). The data presented here, showing internals giving greater decelerative responses, support Davis & Phares’ (1967) suggestion that internals tend to seek information. The correlation between deceleration and acceleration scores following stimulus 16 was not significant ( r = 0.23), and thus information-seeking responses may be independent of the arousal response. Skin conductance recovery time may relate to information intake and defensive aspects of a situation (Edelberg, 1972; Furedy, 1972); longer recovery time being associated with more noxious stimuli and shorter times with an attentional task. Following stimulus 16 externals gave longer recovery times than internals. Moreover, recovery time relates to heart-rate deceleration and acceleration amplitudes appropriately on stimulus 16 ( r = -0.77, P < 0.01 and r = 0.68. P < 0.05 respectively), although not significantly following stimulus one. From the evidence presented here it appears that a reorienting response, elicited by a small change in an otherwise predictable event, may reveal attentional and arousing components of a situation. These in turn relate to the individual’s generalized attitude about his or her ability to influence the environment (locus of control). Acknowledgements We are indebted to Karen McGrath for her assistance in the preparation of this paper. The work was supported by a Medical Research project grant to Professor R. G. Hopkinson, to whom we are also indebted.
References BENNETT, M. D., WEBB,R. & WITHEY,W. R. (1977). Personality, performance and physiological cost during vibration. Journal of Physiology (in press). BULL, K. & LANG,P. J. (1972). Intensity judgements and physiological response amplitude. Psychophysiology, 9, 428-436. COLES.M. G. H., GALE,A. & KLINE. P. (1971). Personality and habituation of the orienting reaction: Tonic and response measures of electrodermal activity. Psychophysiology, 8, 54-63.
W. L. & PHARES, E. J. (1%7). DAVIES, Internakxternal control as a determinant of information-seeking in a social influence situation. Journal of Personality, 35. 547-561. EDELBERG, R. (1972). Electrodermal recovery rate, goal-orientation, and aversion. Psychophysiology. 9.512-520.
FUREDY, J . J. (1972). Electrodermal recovery time as a supra-sensitive autonomic index of anticipated intensity of threatened shock. Psychophysiology, 9, 28 1-282. GLASS,D. C. & SINOER. J. E. (1972). Urban Stress: Experiments on Noise and Social Stressors. New York: Academic Press. GRAHAM, F. K. & CLIITON,R. K. (1966). Heart
rate change as a component of the orienting response. Psychological Bulletin, 65, 305-320. HOUSTON, B. K. (1972). Control over stress, locus of control, and response to stress. Journal of Personality and Social Psychology. 21, 249-255. JOE, V. C. (1971). Review of the internakxternal control construct as a personality variable. Psychological Reporfs, 28. 619440. E. J. KORIAT,A., AVERILL, J. R. & MALMSTROM, (1973). Individual differences in habituation; some methodological and conceptual issues. Journal of Research in Personality, 7. 88-101. LADER,M. H. &WING,L. (1966). Physiological Measures, Sedative Drugs and Morbid Anxiety. London: Oxford University Press. LAZARUS, R. S. (1966). Psychological Stress and the Coping Process. New York: McGraw-Hill. LEFCOURT, H.M. (1972). Recent developments in the study of locus of control. I n B. Maher (ed.), Progress in Experimental Personality Research, vol. 6 . New York: Academic Press. MCGHEE, P. E. & CRANDALL, V. C. (1968). Beliefs in internalexternal control of reinforcement and academic performance. Child Developmenf, 39, 9 1- 102. S . & DUKE,M. P. (1974). A locus of NOWICKI, control scale for non-college as well as college
Orienting responses and locus of control adults. Journal of Personalify Assessment, 38. 136137. ROTTER,J. B. (1954). Social Learning and Clinical Psychology. New York: Prentice-Hall. ROTTER, 3. B. (1966). Generalised expectancies for internal versus external control of reinforcement. Psychological Monographs, 80, whole no. 609. SADLER, T. G., MEFFERD, R. B. & HOUCK,R. L. (1971). The interaction of extraversion and neuroticism in orienting response. Psychophysiology, 8. 312-318.
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STAUB,E., TURSKY, B. & SCHWARTZ. G. E. (1971). Self-control and predictability: Their effects on reactions to aversive stimulation. Journal of Personality afid Social Psychology, 18, 157-162. P. H.& CHRISTIE,M. J. (1973). VENABLES, Mechanisms, instrumentation, techniques and quantification of responses. In W. F. Prokasy & D. C. Raskin (eds), Electrodermal Activity in Psychological Research. New York: Academic Press.
Received 30 March 1977; revised version received 10 June 1977 Requests for reprints should be addressed to Dr T. J. Lobstein. School of Environmental Studies, University College London, Gower Street, London WClE 6BT. Otto Edholm is at the same address. Bob Webb is now at Toronto University.
