Behaa. Res. Thu. Vol. 29, No. 2, pp. 191-196, 1991 Printed in Great Britain. All rights reserved
0005-7967/91 $3.00 + 0.00 Copyright Q 1991 Pergamon Press plc
THE EFFECTS OF FALSE RESPONSE FEEDBACK ON HUMAN ‘FEAR’ CONDITIONING CHRISTINE Department
RUSSELL
and
of Social Sciences, The City University,
GRAHAM
Northampton
C.
L. DAVEY*
Square,
London
EClV OHB, England
(Received 26 January 1990; received for publication I October 1990) Summary-This study describes a human electrodermal conditioning experiment in which subjects were given false skin conductance feedback during CS presentation. In comparison with appropriate attentional control groups, subjects who believed they were exhibiting a strong CR did actually emit a greater magnitude CR, while subjects who believed they were exhibiting only a weak CR emitted a significantly lower magnitude CR. When both self-report and behavioural measures of UCS revaluation were taken after conditioning, the evidence suggested that response feedback had not differentially affected subjects evaluation of the aversiveness of the UCS. The results suggest that the response modulating effects of response feedback observed in this and other studies are not caused by response feedback influencing evaluation of the UCS, but they are consistent with the hypothesis that beliefs about the nature of response feedback influence the strength of the UCS representation itself.
INTRODUCTION
Davey (1987, 1989) has suggested that there are a number of factors which can influence the strength of a Pavlovian conditioned response (CR) other than the strength of the association between the conditioned stimulus (CS) and the unconditioned stimulus (UCS). In many cases these nonassociative factors can be seen to exert their influence by affecting the S’s evaluation of the UCS. For instance, if Ss are given postconditioning habituation training to the UCS which leads them to revalue the UCS more favourably, then there is a subsequent dramatic drop in the strength of the CR on the next CS presentation (Davey & McKenna, 1983). If Ss are given postconditioning presentations of an increased intensity UCS which inflates their evaluation of the UCS, then this produces an increased magnitude CR on subsequent CS presentations (White & Davey, 1989). Similarly, if, during conditioning, Ss are given false feedback which leads them to believe that they are finding the UCS particularly aversive, they consequently emit a stronger CR (Cracknell & Davey, 1988). One other nonassociative factor which produces dramatic differences in CR magnitude and persistance is feedback of the CR itself. Davey (1987) has reported a series of studies in which Ss in electrodermal conditioning studies have been provided with either real or false feedback of their CR levels. These studies have indicated that (i) when the CR is made significantly more discriminable (e.g. by providing discriminable response feedback), Ss actually emit a greater magnitude CR and show a relative resistance to extinction when compared with Ss who have poor CR discrimination; and, (ii) when false CR feedback leads Ss to believe they are emitting a strong CR, they exhibit a resistance to extinction compared with Ss who are led to believe they are emitting only a weak CR. The theoretical conclusion that is frequently drawn from such findings in the false-feedback literature is that information about emotional responding influences the strength of that response by forcing some degree of reappraisal of situational or internal stimuli (cf. Parkinson, 1985; Lazarus, Averill & Opton, 1970). Davey (1988) has argued more specifically that the effects of self-observation of responding in conditioning studies may reflect reappraisal of the UCS, and, as such, may be representative of a much broader range of UCS revaluation phenomena (cf. Davey, 1989). That is, when Ss are able to observe their own reaction to the CS, this provides them with information which contributes to their evaluation of the UCS-if they believe they are emitting a strong fear CR, processes of response attribution will lead them to believe they really do fear the UCS, which in turn facilitates the CR.
*To whom
all correspondence
should
be addressed. 191
192
CHRISTINERUSSELLand GRAHAMC. L. DAVEY
The present experiment attempts revaluation in the modulation of CR using a false-feedback procedure in presentation. Assessments of UCS behavioural methods.
to make a preliminary assessment of the role of UCS strength caused by response feedback. Ss were conditioned which false response feedback was provided during CS evaluation were then made using both self-report and
METHOD
Subjects
The Ss were 28 undergraduate volunteers of both sexes whose ages ranged from 19 to 30 yr. All Ss were naive as to the purpose of the experiment, and a majority had no knowledge of psychology. Apparatus
Skin conductance responses (SCRs) were measured by bipolar placement of 9 mm dia silver/silver chloride (Ag/AgCl) GSR electrodes to the medial phalanx of the first and third fingers of the nonprefered hand. Before the electrodes were attached the S’s fingers were cleansed with methyl alcohol and neptic electrode gel applied to the fingers. Electrodes were secured in place with elastoplast, and these electrodes projected changes in skin conductance level (SCL) onto a Washington 400 MD 2C polygraph via a constant voltage circuit. The experiment was conducted using a 16 K PET microcomputer interfaced with solid-state logic programming equipm5nt located on a bus-bar rack system. Outline figures used as stimuli were projected onto the screen of the microcomputer. All Ss wore headphones which were used to present the false feedback tone and the UCS. The false-feedback tone was a square-wave tone of 65 + 2 dB which could be varied in frequency between 600-800 Hz. The UCS was a 0.5 set burst of a 1000 Hz tone with an intensity of 115 dB. Procedure
On introduction to the experimental room Ss were given written instructions telling them that the experiment was designed to measure sweat gland activity. They were seated in a comfortable chair facing the microcomputer’s visual display unit (VDU) on which the experimental instructions and outline figures were to be displayed. Ss were then fitted with the GSR electrodes and headphones and were told to expect brief instructions displayed on the screen, and to attend to the VDU screen at all times throughout the experiment. Ss were randomly allocated to one of four groups. These groups were labelled (i) Hi-Feedback (Hi) (n = 7), (ii) Lo-Feedback (Lo) (n = 7), (iii) Hi-Control (I%) (n = 7), and (iv) Lo-control (Lo) (n = 7). Ss in the two Feedback groups were told that during the experiment proper the SCR feedback would be switched on only when shapes (CSs) appeared on the VDU screen. They were then told that increases in the frequency of the feedback tone reflected increased perspiring of the palms, and this in turn indicates increasing anxiety. They were similarly informed that decreases in the frequency of the tone meant less perspiring and decreasing anxiety levels. Ss in the Control groups received identical false-feedback to their experimental counterparts but were told at the outset of the experiment that frequency changes had no particular meaning, but they should attend to the tone when it was being presented. These groups represented attentional control groups for whom the feedback had no meaning. The experiment was divided into four phases: (i) a demonstration period, (ii) conditioning, (iii) UCS evaluation self-report, (iv) reconditioning. Demonstration period. This first phase was basically a demonstration period designed to adapt Ss to the stimuli to be used as the CSs in stage 2, and to establish a baseline expectancy of feedback changes in experimental Ss. All four groups received two nonreinforced presentations of a triangle and two nonreinforced presentations of a kitchen tap. Each presentation lasted for 6 set, and was separated by an inter-trial interval of 10 sec. This was immediately followed by a feedback demonstration period in which the false feedback tone was presented continuously for 30 sec. During this period the tone was allowed to step randomly between 600 and 625 HZ. Conditioning. In stage 2 all Ss received six presentations of the triangle (CS+) projected onto the VDU screen followed immediately by the 0.5 set 115 dB tone UCS. Randomly interspersed
Response feedback and fear conditioning
193
amongst these pairings were six presentations of the kitchen tap (CS -). Both CS + and CS - were presented for 6 set with a 20 set inter-trial interval. The VDU screen was blank during all inter-trial intervals. Triangle and tap were counter-balanced as CS + and CS - across Ss. The false-feedback tone was presented only during CS presentations (both CS+ and CS-). SS in all four groups received identical false feedback during CS- in which the tone started randomly at a frequency between 600-800 Hz and, during stimulus presentation, made 3 or 4 random fluctuations over a 20 Hz range. The false feedback presented during CS+, however, differed between Hi and Lo Groups. Ss in the Lo groups received false feedback to CS+ which was generated on the same basis as the false feedback for CS - . For experimental Ss this would indicate no substantial difference between the CR to CS + and CS - . Ss in the Hi Groups received false feedback to the first CS+ presentation generated on the same basis as false feedback to CS(i.e. prior to the first pairing of CS+ with the UCS). On the remaining five CS+ presentations the false feedback tone started randomly at a frequency between 600-800 Hz and, after 1 set of CS+ presentation had elapsed, gradually rose in frequency by between 80-120 Hz before reaching an asymptote just prior to CS+ offset. The rate of this increase in frequency was varied randomly between CS+ presentations. For experimental Ss this manipulation was designed to indicate differential anxiety levels to CS+ and CS - . UC’S ecaluation self-report. At the end of the conditioning stage, Ss were asked to turn over and complete a questionnaire placed next to the VDU screen. This questionnaire asked Ss to rate the aversiveness of the UCS and the CSs on a IO-point scale where 0 = not aversive at all the 10 = very aversive indeed. Ss were also asked to write down what they believed were the relationships between the shapes presented on the VDU screen and the aversive tone. Reconditioning. Stage 4 was used to obtain a behavioural measure of UCS evaluation by reconditioning with novel CSs. In comparison with appropriate control Ss, the rate and strength of differential conditioning in this reconditioning stage should be a function of the evaluation of the UCS (cf. Cracknell & Davey, 1988, for the effects of perceived UCS strength on conditioned responding). In the reconditioning stage Ss were given 3 presentations of a square (CS+) interspersed with 3 presentations of a cross (CS-). CS presentation lasted for 6 set with an intertrial interval of 20 sec. At the start of this stage Ss were informed that the aversive tone UCS may be presented immediately following some of the presentations of the square but never following the cross (a ‘threat’ conditioning procedure). However, no UCS presentations occurred during this stage, and there was no false feedback during CS presentation. A behavioural measure of UCS revaluation was used because (i) there is no reason to suppose that all Ss would understand the notion of aversiveness in a similar way when using the self-report scale, and (ii) there is no reason to suppose that UCS revaluation is always a process that is open to conscious scrutiny by the S. At the end of the experiment all Ss were asked to rate the aversiveness of the square (CS+) and cross (CS-) on the IO-point aversiveness scale. Response
measurement
A CR was considered to be an upward curve of the SCR within 3 set of the onset of the stimulus, and the magnitude of the response was calculated by measuring the distance between the trough and the apex of the curve; all response changes which did not result in an upward curve of the SCR were given zero value. On the small number of trials which exhibited two response peaks, only the first response was measured. All SCR values were treated with a quasi-correction factor used to aid comparison of SCR values across Ss. The formula for this is 4 = SCR/SCR,,, (Lykken, 1972) and SCR,,, was taken as each S’s largest response during the whole experiment. RESULTS Figure 1 shows mean CR magnitude for CS+ aiid CS- for all four groups for the last three trials of the Conditioning stage of the experiment. This exhibited a significant effect of stimulus [F(l, 48) = 57.385, P < O.OOOl] suggesting that all groups had acquired a differential CR to CS+. These data also exhibited a significant Group x stimulus interaction [F(3,48) = 3.124, P < 0.051, in which there was no difference in response magnitude to CS- across groups (all Ps > O.S), but there was a significant difference between groups in response magnitude to CS+ . Pair-wise
194
CHRISTINERUSSELLand GRAHAMC. L. DAVEY
0.8 0.7 0
0.8
2
0.5
1
0.2 0.1 cs*cs-
cs+ cs-
cs+ cs-
Lo
iz
Hi Fig.
CS+
cs-
Lo
I. Mean CR magnitude
(+ SEM) to CS+ (solid bars) and CS- (open bars) for the least three trials of Conditioning for all four groups in the experiment.
comparisons of CR magnitude to CS + indicated that Group Hi exhibited a greater magnitude CR than all other groups (all ts > 2.6, all Ps < 0.02), and that Group Lo exhibited a significantly lower magnitude CR than all other groups (all ts > 2.4, all Ps < 0.05). There was no significant difference in CR magnitude to CS+ between the two attentional control groups K and Lo. Table 1 lists the mean aversiveness ratings to the UCS, CS + and CS - used in the Conditioning stage of the experiment, and the new CS+ and CSused in the Reconditioning stage of the experiment. Although Ss in Group Hi gave the UCS a higher mean aversiveness rating than Ss in the other three groups, there was no significant difference between groups in this measure (P > 0.1). Aversiveness ratings to CS + and CS - during the Conditioning stage of the experiment exhibited a significant effect of stimulus [F(l, 48) = 95.682, P < O.OOOl], suggesting that Ss generally found CS+ more aversive than CS -. However, there was no Group x stimulus interaction, suggesting that the between-groups CR magnitude effect found in the Conditioning stage was not reflected in between-group differences in the rating of the aversiveness of CS + . Finally, in the Reconditioning stage, Ss in all groups rated CS+ as more aversive than CS[F(l, 48) = 128.000, P < O.OOOl], but, as in the Conditioning stage, there was no significant Group x stimulus interaction (F < 1). Figure 2 shows the mean CR magnitude to CS+ and CSin all four groups for the three Reconditioning trials. This exhibited a significant effect of stimulus [a(l, 48) = 5.157, P < 0.051, indicating higher SCR levels to CS+ than CS-. However, there was no significant Group x stimulus interaction (F < 1.7) indicating no between-group differences in response magnitude to CS + . Nevertheless, since the Reconditioning stage was basically a threat procedure in which no UCS presentations occurred, it is possible that any between-group differences may only be manifested during early trials before Ss begin to realise that no UCSs will be presented. However, even when CR magnitude to only the first CS + presentation in the Reconditioning stage is analysed (at a time when Ss would not be aware that there would be no more UCS presentations), there is still no significant difference between groups (P > 0.1). At the end of the experiment all Ss were asked to give their impressions of the response feedback. None of the Ss in Groups Hi and Lo were aware that the feedback was false. Table
I. Mean aver~wene~ratings (f SEM) for UCS, CS+ and CS - after conditioning and the novel CS+ and CS-
after reconditioning Reconditioning
Conditioning GKXlp Hi Lo Hi Lo
ucs 7.85 i_ 0.26 7.42 k 0.48 7.28 + 0.28 7.14 f 0.50
cs-
cs+ 7.28 + 7.14 * 7.57 f 7.14 *
0.56 0.40 0.20 0.40
2.57 i 2.71 + 3.00 i 3.85 i
cs-
cs+ 0.68 0.64 0.81 0.88
6.14 F 5.14 k 6.57 i 4.57 +
0.79 0.63 0.52 0.60
1.14iO.63 1.14 * 0.33 1.00 f 0.30 0.85 + 0.55
Response
feedback
195
and fear conditioning
cs* cs-
cs* cs-
cs* cs-
Hi
Lo
iii
cs* csL-o
Fig. 2. Mean CR magnitude (k SEM) to the novel CS + (solid bars) and the novel CS - (open bars) for the three trials of Reconditioning for all four groups in the experiment.
DISCUSSION
This study has replicated the finding of Davey (1987) that CR strength in a differential conditioning procedure will be influenced by the nature of response feedback given to Ss. In comparison with appropriate attentional control groups, Ss who are led to believe they are emitting a strong CR actually do emit a higher magnitude CR; Ss who are led to believe they are emitting a weak CR actually do emit a significantly lower magnitude CR. These data supplement other studies which show that Ss who believe they are emitting a strong CR also take longer to extinguish than Ss who believe they are emitting only a weak CR (cf. Davey, 1987). Davey (1988) has speculated that the response modulating effects of response feedback may have their effect via processes of UCS revaluation; that is, observing oneself emitting a strong CR leads one to attribute appropriate aversive properties to the UCS, this evaluation in turn leads to stronger CRs on future CS presentations. However, contrary to this speculation, there was no evidence in the present study for any UCS revaluation occurring as a result of response feedback. There were no between-group differences in self-report ratings of the aversiveness of the UCS, nor were there any between-group differences in the behavioural measure of UCS evaluation taken during Reconditioning. Nevertheless, the present experiment provided further clear evidence for the response modulating effects of response feedback, so what processes other than revaluation of UCS aversiveness might be responsible for this phenomenon? First, the SCR is a response which does not just reflect components of the defensive systems implicated during aversive conditioning, but is also an indicator of generalised orienting reactions (Siddle, 1983) and centralised information processing (ohman, 1979). If this is the case, then providing immediate SCL feedback during CS presentation represents extra information that requires processing during CS presentation. Because the SCL feedback provides new information on each trial, the SCR produced by the processing of this information may combine with the conditioned SCR to produce a larger magnitude CR. Davey (1987) has argued that this explanation is highly unlikely for a number of reasons: (i) feedback contains intrinsic information and not extrinsic information, and as such is not a signal calling for processing space; the vast majority of studies that have investigated intrinsic information have reported no effect of this variable on SCR strength (e.g. Becker & Shapiro, 1980; Pendergrass & Kimmel, 1968); (ii) if feedback represents extra information to be processed during CS presentation, then SCR magnitude should not differ between Lo and Hi groups since both groups have extra information to process during CS presentation. This, however, is not the case. In fact Ss in Group Lo exhibit SCR levels which are lower than attentional control Ss; and (iii) Davey (1987) found that the response modulating effects of response feedback could be found even when response feedback was presented during the inter-trial interval and not during CS presentation. This suggests that the response modulating
196
CHRISTINE RUSSELL and GRAHAM C. L. DAVEY
effects of response feedback are not due to the extra information processing requirements imposed when feedback is given during CS presentation. Clearly, the fact that Ss in Group Hi emit a greafer magnitude CR than attentional controls, and SS in Group Lo emit a lower magnitude CR than attentional controls implies that the qualitative way in which the feedback is interpreted plays a major role in determining response strength. The theoretical question remaining concerns the kind of processes that beliefs about response strength influence in order to produce their effects. The present study provides little evidence that these beliefs influence the aversive evaluation of the UCS; nor, it seems, do these beliefs substantially influence individual estimation of the aversiveness of the CS itself. In the light of this evidence, one alternative possibility is that beliefs about response strength do not influence the aversive evaluation of events such as the UCS, but affect the moment-to-moment strength of the UCS representation itself. That is, while response feedback may not affect UCS evaluation, it may influence the rate at which the UCS representation is established or the rate at which it will deteriorate. For example, believing that your response to the CS is relatively insignificant (Group Lo) may lead to reduced processing of the CS which in turn results in weakened activation of the UCS representation; believing that your response to the CS is relatively strong (Group Hi), however, may lead to intensive processing of the CS which readily activates a strong UCS representation. In this case, CR strength is determined by the strength of activation of the UCS representation-not by altered evaluation of the UCS. Explanation of response feedback effects in terms of its influence on the strength of the UCS representation does not require that Ss alter their evaluation of the aversiveness of the UCS or the CS, and it is also consistent with Davey’s (1987) findings that persistance of the CR during extinction is a direct function of the Ss’ beliefs about the strength of their CR. Nevertheless, regardless of the nature of the exact mechanism which underlies the response feedback effect, this phenomenon has a number of implications for the persistance and amelioration of clinical fears. The most obvious implications are that the strength or persistance of a fear or anxiety response will be affected by (i) the tendency that the individual has to focus in on and discriminate their own physiological reactions to the fearful situation, and (ii) beliefs that the individual holds about the strength of their fear response (whether true or false, or whether acquired directly from response feedback or other sources). Furthermore, the present results show that convincing the S that their fear CR is weak actually attenuates CR strength. This suggests that any means by which the anxious or phobic individual can be led to believe that their fear or anxiety reaction is weak should have a desired therapeutic effect on both the magnitude and persistance of the fear response. REFERENCES Becker, D. E. & Shaprio, D. (1980). Directing attention towards stimuli affects the P300 but not the orienting response. Psychophysiology, 17, 385-389. Cracknell, S. & Davey, G. C. L. (1988). The effect of perceived unconditioned response strength on conditioned responding in humans. Medical Science Research, 16, 169-170. Davey, G. C. L. (1987). An integration of human and animal models of Pavlovian conditioning: Associations, cognitions and attributions. In Davey, G. C. L. (Ed.), Cognitive processes and Pavlovian conditioning in humans. Chichester: Wiley. Davey, G. C. L. (1988). Pavlovian conditioning in humans: UCS revaluation and self-observation of conditioned responding. Medical Science Research, 16, 957-961. Davey, G. C. L. (1989). UCS revaluation and conditioning models of acquired fears. Behauiour Research and Therapy 27, 521-528. Davey, G. C. L. & McKenna, I. (1983). The effect of postconditioning revaluation of CSl and UCS following Pavlovian second-order electrodermal conditioning in humans. Quarterly Journal of Experimental Psychology, 35B, 125-133. Lazarus, R. S., Averill, J. R. & Opton, E. M. (1970). Towards a cognitive theory of emotion. In Arnold, M. B. (Ed.), Feelings and emotions: The Loyola symposium. New York: Academic Press. Lykken, D. T. (1972). Range correction applied to heart rate and GSR data. Psychophysiology, 9, 373-382. ohman, A. (1979). The orienting response, attention, and learning: An information-processing perspective. In Kimmel, F. H., Van Olst, E. H. & Orlebecke, J. F. (Eds), The orienfing reflex in humans. Hillsdale, N.J.: Erlbaum. Parkinson, B. (1985). Emotional effects of false autonomic feedback. Psychology Bulletin, 98, 471494. Pendergrass, V. E. & Kimmel, H. D. (1968). UCR domination in temporal conditioning and habituation. Journal O/ Experimental Psychology, 77, 14. Siddle, D. (1983). Orienting and habituation: Perspectives in human research. Chichester: Wiley. White, K. & Davey, G. C. L. (1989). Sensory preconditioning and UCS inflation in human ‘fear’ conditioning. Behaviour Research & Therapy, 27, 161-166.
0005-7967/91 $3.00 + 0.00 Copyright Q 1991 Pergamon Press plc
THE EFFECTS OF FALSE RESPONSE FEEDBACK ON HUMAN ‘FEAR’ CONDITIONING CHRISTINE Department
RUSSELL
and
of Social Sciences, The City University,
GRAHAM
Northampton
C.
L. DAVEY*
Square,
London
EClV OHB, England
(Received 26 January 1990; received for publication I October 1990) Summary-This study describes a human electrodermal conditioning experiment in which subjects were given false skin conductance feedback during CS presentation. In comparison with appropriate attentional control groups, subjects who believed they were exhibiting a strong CR did actually emit a greater magnitude CR, while subjects who believed they were exhibiting only a weak CR emitted a significantly lower magnitude CR. When both self-report and behavioural measures of UCS revaluation were taken after conditioning, the evidence suggested that response feedback had not differentially affected subjects evaluation of the aversiveness of the UCS. The results suggest that the response modulating effects of response feedback observed in this and other studies are not caused by response feedback influencing evaluation of the UCS, but they are consistent with the hypothesis that beliefs about the nature of response feedback influence the strength of the UCS representation itself.
INTRODUCTION
Davey (1987, 1989) has suggested that there are a number of factors which can influence the strength of a Pavlovian conditioned response (CR) other than the strength of the association between the conditioned stimulus (CS) and the unconditioned stimulus (UCS). In many cases these nonassociative factors can be seen to exert their influence by affecting the S’s evaluation of the UCS. For instance, if Ss are given postconditioning habituation training to the UCS which leads them to revalue the UCS more favourably, then there is a subsequent dramatic drop in the strength of the CR on the next CS presentation (Davey & McKenna, 1983). If Ss are given postconditioning presentations of an increased intensity UCS which inflates their evaluation of the UCS, then this produces an increased magnitude CR on subsequent CS presentations (White & Davey, 1989). Similarly, if, during conditioning, Ss are given false feedback which leads them to believe that they are finding the UCS particularly aversive, they consequently emit a stronger CR (Cracknell & Davey, 1988). One other nonassociative factor which produces dramatic differences in CR magnitude and persistance is feedback of the CR itself. Davey (1987) has reported a series of studies in which Ss in electrodermal conditioning studies have been provided with either real or false feedback of their CR levels. These studies have indicated that (i) when the CR is made significantly more discriminable (e.g. by providing discriminable response feedback), Ss actually emit a greater magnitude CR and show a relative resistance to extinction when compared with Ss who have poor CR discrimination; and, (ii) when false CR feedback leads Ss to believe they are emitting a strong CR, they exhibit a resistance to extinction compared with Ss who are led to believe they are emitting only a weak CR. The theoretical conclusion that is frequently drawn from such findings in the false-feedback literature is that information about emotional responding influences the strength of that response by forcing some degree of reappraisal of situational or internal stimuli (cf. Parkinson, 1985; Lazarus, Averill & Opton, 1970). Davey (1988) has argued more specifically that the effects of self-observation of responding in conditioning studies may reflect reappraisal of the UCS, and, as such, may be representative of a much broader range of UCS revaluation phenomena (cf. Davey, 1989). That is, when Ss are able to observe their own reaction to the CS, this provides them with information which contributes to their evaluation of the UCS-if they believe they are emitting a strong fear CR, processes of response attribution will lead them to believe they really do fear the UCS, which in turn facilitates the CR.
*To whom
all correspondence
should
be addressed. 191
192
CHRISTINERUSSELLand GRAHAMC. L. DAVEY
The present experiment attempts revaluation in the modulation of CR using a false-feedback procedure in presentation. Assessments of UCS behavioural methods.
to make a preliminary assessment of the role of UCS strength caused by response feedback. Ss were conditioned which false response feedback was provided during CS evaluation were then made using both self-report and
METHOD
Subjects
The Ss were 28 undergraduate volunteers of both sexes whose ages ranged from 19 to 30 yr. All Ss were naive as to the purpose of the experiment, and a majority had no knowledge of psychology. Apparatus
Skin conductance responses (SCRs) were measured by bipolar placement of 9 mm dia silver/silver chloride (Ag/AgCl) GSR electrodes to the medial phalanx of the first and third fingers of the nonprefered hand. Before the electrodes were attached the S’s fingers were cleansed with methyl alcohol and neptic electrode gel applied to the fingers. Electrodes were secured in place with elastoplast, and these electrodes projected changes in skin conductance level (SCL) onto a Washington 400 MD 2C polygraph via a constant voltage circuit. The experiment was conducted using a 16 K PET microcomputer interfaced with solid-state logic programming equipm5nt located on a bus-bar rack system. Outline figures used as stimuli were projected onto the screen of the microcomputer. All Ss wore headphones which were used to present the false feedback tone and the UCS. The false-feedback tone was a square-wave tone of 65 + 2 dB which could be varied in frequency between 600-800 Hz. The UCS was a 0.5 set burst of a 1000 Hz tone with an intensity of 115 dB. Procedure
On introduction to the experimental room Ss were given written instructions telling them that the experiment was designed to measure sweat gland activity. They were seated in a comfortable chair facing the microcomputer’s visual display unit (VDU) on which the experimental instructions and outline figures were to be displayed. Ss were then fitted with the GSR electrodes and headphones and were told to expect brief instructions displayed on the screen, and to attend to the VDU screen at all times throughout the experiment. Ss were randomly allocated to one of four groups. These groups were labelled (i) Hi-Feedback (Hi) (n = 7), (ii) Lo-Feedback (Lo) (n = 7), (iii) Hi-Control (I%) (n = 7), and (iv) Lo-control (Lo) (n = 7). Ss in the two Feedback groups were told that during the experiment proper the SCR feedback would be switched on only when shapes (CSs) appeared on the VDU screen. They were then told that increases in the frequency of the feedback tone reflected increased perspiring of the palms, and this in turn indicates increasing anxiety. They were similarly informed that decreases in the frequency of the tone meant less perspiring and decreasing anxiety levels. Ss in the Control groups received identical false-feedback to their experimental counterparts but were told at the outset of the experiment that frequency changes had no particular meaning, but they should attend to the tone when it was being presented. These groups represented attentional control groups for whom the feedback had no meaning. The experiment was divided into four phases: (i) a demonstration period, (ii) conditioning, (iii) UCS evaluation self-report, (iv) reconditioning. Demonstration period. This first phase was basically a demonstration period designed to adapt Ss to the stimuli to be used as the CSs in stage 2, and to establish a baseline expectancy of feedback changes in experimental Ss. All four groups received two nonreinforced presentations of a triangle and two nonreinforced presentations of a kitchen tap. Each presentation lasted for 6 set, and was separated by an inter-trial interval of 10 sec. This was immediately followed by a feedback demonstration period in which the false feedback tone was presented continuously for 30 sec. During this period the tone was allowed to step randomly between 600 and 625 HZ. Conditioning. In stage 2 all Ss received six presentations of the triangle (CS+) projected onto the VDU screen followed immediately by the 0.5 set 115 dB tone UCS. Randomly interspersed
Response feedback and fear conditioning
193
amongst these pairings were six presentations of the kitchen tap (CS -). Both CS + and CS - were presented for 6 set with a 20 set inter-trial interval. The VDU screen was blank during all inter-trial intervals. Triangle and tap were counter-balanced as CS + and CS - across Ss. The false-feedback tone was presented only during CS presentations (both CS+ and CS-). SS in all four groups received identical false feedback during CS- in which the tone started randomly at a frequency between 600-800 Hz and, during stimulus presentation, made 3 or 4 random fluctuations over a 20 Hz range. The false feedback presented during CS+, however, differed between Hi and Lo Groups. Ss in the Lo groups received false feedback to CS+ which was generated on the same basis as the false feedback for CS - . For experimental Ss this would indicate no substantial difference between the CR to CS + and CS - . Ss in the Hi Groups received false feedback to the first CS+ presentation generated on the same basis as false feedback to CS(i.e. prior to the first pairing of CS+ with the UCS). On the remaining five CS+ presentations the false feedback tone started randomly at a frequency between 600-800 Hz and, after 1 set of CS+ presentation had elapsed, gradually rose in frequency by between 80-120 Hz before reaching an asymptote just prior to CS+ offset. The rate of this increase in frequency was varied randomly between CS+ presentations. For experimental Ss this manipulation was designed to indicate differential anxiety levels to CS+ and CS - . UC’S ecaluation self-report. At the end of the conditioning stage, Ss were asked to turn over and complete a questionnaire placed next to the VDU screen. This questionnaire asked Ss to rate the aversiveness of the UCS and the CSs on a IO-point scale where 0 = not aversive at all the 10 = very aversive indeed. Ss were also asked to write down what they believed were the relationships between the shapes presented on the VDU screen and the aversive tone. Reconditioning. Stage 4 was used to obtain a behavioural measure of UCS evaluation by reconditioning with novel CSs. In comparison with appropriate control Ss, the rate and strength of differential conditioning in this reconditioning stage should be a function of the evaluation of the UCS (cf. Cracknell & Davey, 1988, for the effects of perceived UCS strength on conditioned responding). In the reconditioning stage Ss were given 3 presentations of a square (CS+) interspersed with 3 presentations of a cross (CS-). CS presentation lasted for 6 set with an intertrial interval of 20 sec. At the start of this stage Ss were informed that the aversive tone UCS may be presented immediately following some of the presentations of the square but never following the cross (a ‘threat’ conditioning procedure). However, no UCS presentations occurred during this stage, and there was no false feedback during CS presentation. A behavioural measure of UCS revaluation was used because (i) there is no reason to suppose that all Ss would understand the notion of aversiveness in a similar way when using the self-report scale, and (ii) there is no reason to suppose that UCS revaluation is always a process that is open to conscious scrutiny by the S. At the end of the experiment all Ss were asked to rate the aversiveness of the square (CS+) and cross (CS-) on the IO-point aversiveness scale. Response
measurement
A CR was considered to be an upward curve of the SCR within 3 set of the onset of the stimulus, and the magnitude of the response was calculated by measuring the distance between the trough and the apex of the curve; all response changes which did not result in an upward curve of the SCR were given zero value. On the small number of trials which exhibited two response peaks, only the first response was measured. All SCR values were treated with a quasi-correction factor used to aid comparison of SCR values across Ss. The formula for this is 4 = SCR/SCR,,, (Lykken, 1972) and SCR,,, was taken as each S’s largest response during the whole experiment. RESULTS Figure 1 shows mean CR magnitude for CS+ aiid CS- for all four groups for the last three trials of the Conditioning stage of the experiment. This exhibited a significant effect of stimulus [F(l, 48) = 57.385, P < O.OOOl] suggesting that all groups had acquired a differential CR to CS+. These data also exhibited a significant Group x stimulus interaction [F(3,48) = 3.124, P < 0.051, in which there was no difference in response magnitude to CS- across groups (all Ps > O.S), but there was a significant difference between groups in response magnitude to CS+ . Pair-wise
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CHRISTINERUSSELLand GRAHAMC. L. DAVEY
0.8 0.7 0
0.8
2
0.5
1
0.2 0.1 cs*cs-
cs+ cs-
cs+ cs-
Lo
iz
Hi Fig.
CS+
cs-
Lo
I. Mean CR magnitude
(+ SEM) to CS+ (solid bars) and CS- (open bars) for the least three trials of Conditioning for all four groups in the experiment.
comparisons of CR magnitude to CS + indicated that Group Hi exhibited a greater magnitude CR than all other groups (all ts > 2.6, all Ps < 0.02), and that Group Lo exhibited a significantly lower magnitude CR than all other groups (all ts > 2.4, all Ps < 0.05). There was no significant difference in CR magnitude to CS+ between the two attentional control groups K and Lo. Table 1 lists the mean aversiveness ratings to the UCS, CS + and CS - used in the Conditioning stage of the experiment, and the new CS+ and CSused in the Reconditioning stage of the experiment. Although Ss in Group Hi gave the UCS a higher mean aversiveness rating than Ss in the other three groups, there was no significant difference between groups in this measure (P > 0.1). Aversiveness ratings to CS + and CS - during the Conditioning stage of the experiment exhibited a significant effect of stimulus [F(l, 48) = 95.682, P < O.OOOl], suggesting that Ss generally found CS+ more aversive than CS -. However, there was no Group x stimulus interaction, suggesting that the between-groups CR magnitude effect found in the Conditioning stage was not reflected in between-group differences in the rating of the aversiveness of CS + . Finally, in the Reconditioning stage, Ss in all groups rated CS+ as more aversive than CS[F(l, 48) = 128.000, P < O.OOOl], but, as in the Conditioning stage, there was no significant Group x stimulus interaction (F < 1). Figure 2 shows the mean CR magnitude to CS+ and CSin all four groups for the three Reconditioning trials. This exhibited a significant effect of stimulus [a(l, 48) = 5.157, P < 0.051, indicating higher SCR levels to CS+ than CS-. However, there was no significant Group x stimulus interaction (F < 1.7) indicating no between-group differences in response magnitude to CS + . Nevertheless, since the Reconditioning stage was basically a threat procedure in which no UCS presentations occurred, it is possible that any between-group differences may only be manifested during early trials before Ss begin to realise that no UCSs will be presented. However, even when CR magnitude to only the first CS + presentation in the Reconditioning stage is analysed (at a time when Ss would not be aware that there would be no more UCS presentations), there is still no significant difference between groups (P > 0.1). At the end of the experiment all Ss were asked to give their impressions of the response feedback. None of the Ss in Groups Hi and Lo were aware that the feedback was false. Table
I. Mean aver~wene~ratings (f SEM) for UCS, CS+ and CS - after conditioning and the novel CS+ and CS-
after reconditioning Reconditioning
Conditioning GKXlp Hi Lo Hi Lo
ucs 7.85 i_ 0.26 7.42 k 0.48 7.28 + 0.28 7.14 f 0.50
cs-
cs+ 7.28 + 7.14 * 7.57 f 7.14 *
0.56 0.40 0.20 0.40
2.57 i 2.71 + 3.00 i 3.85 i
cs-
cs+ 0.68 0.64 0.81 0.88
6.14 F 5.14 k 6.57 i 4.57 +
0.79 0.63 0.52 0.60
1.14iO.63 1.14 * 0.33 1.00 f 0.30 0.85 + 0.55
Response
feedback
195
and fear conditioning
cs* cs-
cs* cs-
cs* cs-
Hi
Lo
iii
cs* csL-o
Fig. 2. Mean CR magnitude (k SEM) to the novel CS + (solid bars) and the novel CS - (open bars) for the three trials of Reconditioning for all four groups in the experiment.
DISCUSSION
This study has replicated the finding of Davey (1987) that CR strength in a differential conditioning procedure will be influenced by the nature of response feedback given to Ss. In comparison with appropriate attentional control groups, Ss who are led to believe they are emitting a strong CR actually do emit a higher magnitude CR; Ss who are led to believe they are emitting a weak CR actually do emit a significantly lower magnitude CR. These data supplement other studies which show that Ss who believe they are emitting a strong CR also take longer to extinguish than Ss who believe they are emitting only a weak CR (cf. Davey, 1987). Davey (1988) has speculated that the response modulating effects of response feedback may have their effect via processes of UCS revaluation; that is, observing oneself emitting a strong CR leads one to attribute appropriate aversive properties to the UCS, this evaluation in turn leads to stronger CRs on future CS presentations. However, contrary to this speculation, there was no evidence in the present study for any UCS revaluation occurring as a result of response feedback. There were no between-group differences in self-report ratings of the aversiveness of the UCS, nor were there any between-group differences in the behavioural measure of UCS evaluation taken during Reconditioning. Nevertheless, the present experiment provided further clear evidence for the response modulating effects of response feedback, so what processes other than revaluation of UCS aversiveness might be responsible for this phenomenon? First, the SCR is a response which does not just reflect components of the defensive systems implicated during aversive conditioning, but is also an indicator of generalised orienting reactions (Siddle, 1983) and centralised information processing (ohman, 1979). If this is the case, then providing immediate SCL feedback during CS presentation represents extra information that requires processing during CS presentation. Because the SCL feedback provides new information on each trial, the SCR produced by the processing of this information may combine with the conditioned SCR to produce a larger magnitude CR. Davey (1987) has argued that this explanation is highly unlikely for a number of reasons: (i) feedback contains intrinsic information and not extrinsic information, and as such is not a signal calling for processing space; the vast majority of studies that have investigated intrinsic information have reported no effect of this variable on SCR strength (e.g. Becker & Shapiro, 1980; Pendergrass & Kimmel, 1968); (ii) if feedback represents extra information to be processed during CS presentation, then SCR magnitude should not differ between Lo and Hi groups since both groups have extra information to process during CS presentation. This, however, is not the case. In fact Ss in Group Lo exhibit SCR levels which are lower than attentional control Ss; and (iii) Davey (1987) found that the response modulating effects of response feedback could be found even when response feedback was presented during the inter-trial interval and not during CS presentation. This suggests that the response modulating
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CHRISTINE RUSSELL and GRAHAM C. L. DAVEY
effects of response feedback are not due to the extra information processing requirements imposed when feedback is given during CS presentation. Clearly, the fact that Ss in Group Hi emit a greafer magnitude CR than attentional controls, and SS in Group Lo emit a lower magnitude CR than attentional controls implies that the qualitative way in which the feedback is interpreted plays a major role in determining response strength. The theoretical question remaining concerns the kind of processes that beliefs about response strength influence in order to produce their effects. The present study provides little evidence that these beliefs influence the aversive evaluation of the UCS; nor, it seems, do these beliefs substantially influence individual estimation of the aversiveness of the CS itself. In the light of this evidence, one alternative possibility is that beliefs about response strength do not influence the aversive evaluation of events such as the UCS, but affect the moment-to-moment strength of the UCS representation itself. That is, while response feedback may not affect UCS evaluation, it may influence the rate at which the UCS representation is established or the rate at which it will deteriorate. For example, believing that your response to the CS is relatively insignificant (Group Lo) may lead to reduced processing of the CS which in turn results in weakened activation of the UCS representation; believing that your response to the CS is relatively strong (Group Hi), however, may lead to intensive processing of the CS which readily activates a strong UCS representation. In this case, CR strength is determined by the strength of activation of the UCS representation-not by altered evaluation of the UCS. Explanation of response feedback effects in terms of its influence on the strength of the UCS representation does not require that Ss alter their evaluation of the aversiveness of the UCS or the CS, and it is also consistent with Davey’s (1987) findings that persistance of the CR during extinction is a direct function of the Ss’ beliefs about the strength of their CR. Nevertheless, regardless of the nature of the exact mechanism which underlies the response feedback effect, this phenomenon has a number of implications for the persistance and amelioration of clinical fears. The most obvious implications are that the strength or persistance of a fear or anxiety response will be affected by (i) the tendency that the individual has to focus in on and discriminate their own physiological reactions to the fearful situation, and (ii) beliefs that the individual holds about the strength of their fear response (whether true or false, or whether acquired directly from response feedback or other sources). Furthermore, the present results show that convincing the S that their fear CR is weak actually attenuates CR strength. This suggests that any means by which the anxious or phobic individual can be led to believe that their fear or anxiety reaction is weak should have a desired therapeutic effect on both the magnitude and persistance of the fear response. REFERENCES Becker, D. E. & Shaprio, D. (1980). Directing attention towards stimuli affects the P300 but not the orienting response. Psychophysiology, 17, 385-389. Cracknell, S. & Davey, G. C. L. (1988). The effect of perceived unconditioned response strength on conditioned responding in humans. Medical Science Research, 16, 169-170. Davey, G. C. L. (1987). An integration of human and animal models of Pavlovian conditioning: Associations, cognitions and attributions. In Davey, G. C. L. (Ed.), Cognitive processes and Pavlovian conditioning in humans. Chichester: Wiley. Davey, G. C. L. (1988). Pavlovian conditioning in humans: UCS revaluation and self-observation of conditioned responding. Medical Science Research, 16, 957-961. Davey, G. C. L. (1989). UCS revaluation and conditioning models of acquired fears. Behauiour Research and Therapy 27, 521-528. Davey, G. C. L. & McKenna, I. (1983). The effect of postconditioning revaluation of CSl and UCS following Pavlovian second-order electrodermal conditioning in humans. Quarterly Journal of Experimental Psychology, 35B, 125-133. Lazarus, R. S., Averill, J. R. & Opton, E. M. (1970). Towards a cognitive theory of emotion. In Arnold, M. B. (Ed.), Feelings and emotions: The Loyola symposium. New York: Academic Press. Lykken, D. T. (1972). Range correction applied to heart rate and GSR data. Psychophysiology, 9, 373-382. ohman, A. (1979). The orienting response, attention, and learning: An information-processing perspective. In Kimmel, F. H., Van Olst, E. H. & Orlebecke, J. F. (Eds), The orienfing reflex in humans. Hillsdale, N.J.: Erlbaum. Parkinson, B. (1985). Emotional effects of false autonomic feedback. Psychology Bulletin, 98, 471494. Pendergrass, V. E. & Kimmel, H. D. (1968). UCR domination in temporal conditioning and habituation. Journal O/ Experimental Psychology, 77, 14. Siddle, D. (1983). Orienting and habituation: Perspectives in human research. Chichester: Wiley. White, K. & Davey, G. C. L. (1989). Sensory preconditioning and UCS inflation in human ‘fear’ conditioning. Behaviour Research & Therapy, 27, 161-166.
