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The effects of reward and punishment on response disinhibition, moods, heart rate and skin conductance level during instrumental learning
Pergamon PII:
Person. indirid. D# Vol. 23, No. 2, pp. 305-316, 1997 CI1997 Elsevier Science Ltd. All rights reserved Printed in Great Britain 0191.8869/97 $17.00+0.00 SO191-8869(97)00031-7
THE EFFECTS OF REWARD AND PUNISHMENT ON RESPONSE DISINHIBITION, MOODS, HEART RATE AND SKIN CONDUCTANCE LEVEL DURING INSTRUMENTAL LEARNING Rapson School of Behavioural
Gomez*
and Suzanne
McLaren
and Social Sciences and Humanities, University Ballarat, 3350, Victoria, Australia (Received
9 September
of Ballarat,
Gear Avenue,
I!&%/
Summary-The study examined the effects of reward and punishment on response disinhibition, happy and nervous moods, heart rate and skin conductance levels during performance of an instrumental learning task. For one group of subjects (the reward group), correct responses were reinforced with a small monetary reward, while for another group (the punishment group), incorrect responses led to a small loss of money. Results indicated that subjects in the punishment group made fewer disinhibitory responses, were more nervous and less happy, and had a higher skin conductance level compared with subjects in the reward group. For both groups, these measures (and heart rate) did not correlate with each other, or with trait impulsivity or trait anxiety. These findings are discussed in relation to Gray’s theory of behavioural inhibition system (BIS) and behavioural approach system (BAS). c] 1997 Elsevier Science Ltd
INTRODUCTION
Eysenck’s (1967) theory of personality suggests two orthogonally related neurological based dimensions of personality: Extraversion-Introversion and NeuroticismPStability. J. A. Gray (1970) also proposed two orthogonal dimensions of personality, these being Anxiety and Impulsivity. In relating his own theory to that of Eysenck’s, Gray (1970, 1987) has proposed that in terms of a twodimensional space defined by Extraversion-Introversion and Neuroticism-Stability, the anxiety axis runs from the stable-extravert quadrant to the neurotic-introvert quadrant, while the impulsivity axis runs from the stable-introvert quadrant to the neurotic-extravert quadrant. On the anxiety axis, high anxious individuals are in the neurotic introvert quadrant and low anxious individuals are in the stable extravert quadrant. In terms of the impulsivity axis, high impulsive individuals are in the neurotic extravert quadrant, while low impulsive individuals are in the stable introvert quadrant. Based on animal learning, pharmacological and lesion studies, Gray (1970, 1981, 1990) has proposed that the anxiety and impulsivity dimensions of personality reflect two structurally distinct neurophysiological systems that differ in their sensitivities to reward and punishment cues. The neural substrates of anxiety were referred to as the behavioural inhibition system (BIS), while those related to impulsivity were referred to as the behavioural approach system (BAS). According to Gray (1982), the neural substrates of the BIS are the septohippocampal systems, including the monoaminergic afferents from the brainstem and the neocortical projection to the frontal lobe, while the neurological substrates of the BAS are the catecholaminergic (especially dopaminergic) pathways to the mesolimbic system. Gray’s (1970, 1990) theory suggests that activation of the BIS and the BAS lead to different behaviours and emotions. In relation to behaviour, this theory suggests that the BIS is sensitive to signals of punishment, frustrative non-reward and novelty, and when it is activated by such signals, it inhibits behaviour that will lead to further negative or painful outcomes. In contrast, the BAS is believed to be sensitive to signals of reward and non-punishment, and when it is activated by such signals, it causes or increases behaviour toward more rewards or goals. Thus, the BIS is activated by punishment, and is involved in regulating aversive motivation. The BAS is activated by reward, and is involved in regulating appetitive motivation. In terms of emotions, Gray (1990) has suggested
*To whom all correspondence
should be addressed. 305
306
Rapson Gomez and Suzanne McLaren
that activation of the BIS leads to negative affects such as anxiety, fear, frustration, and sadness, while activation of the BAS leads to positive affects such as happiness, hope, and elation. As pointed out earlier, Gray’s theory was developed primarily on animal studies. In recent years researchers have begun examining hypotheses derived from Gray’s theory with human Ss (e.g. Carver & White, 1994; Geen, 1987; Hagopian & Ollendick, 1994; Newman, Patterson & Kosson, 1987). Several studies have evaluated the activity of the BAS in relation to response disinhibition using response perseveration and passive avoidance learning paradigms (e.g. Gorenstein & Newman, 1980; Patterson & Newman, 1993). Perseveration refers to an exaggerated tendency to emit a dominant response despite punishment (McCleary, 1966) while passive avoidance learning refers to withholding a response (often an appetitively motivated one) to avoid punishment by learning cues that predict it (Patterson & Newman, 1993). Evidence suggests that when both reward and punishment are present, disinhibited individuals (such as psychopath adults and delinquent adolescents) exhibit more perseverative responses (Gorenstein & Newman, 1980; Newman et al., 1987) and more commission error responses (an index of response disinhibition) on passive avoidance learning tasks (Newman & Kosson, 1986; Newman, Widom & Nathan, 1985) than controls. There is also evidence that college students grouped as ‘neurotic extravert’ (individuals with high BAS sensitivity) obtained more errors of commission on a passive avoidance discrimination task in the presence of reward cues than when only punishment cues were present (Newman, 1987). These findings suggest that for impulsive individuals, the BAS is more sensitive than the BIS when rewards are present. This interpretation is consistent with Gray’s theory. In general, these studies provide indirect support for Gray’s theory. In relation to emotions, Carver and White (1994) reported that when Ss anticipated rewards, a significant positive correlation between BAS sensitivity and happiness was found, but there was no relationship between BIS sensitivity and happiness. Studies that have examined the BIS have demonstrated that individuals with high test anxiety made fewer impulsive responses on signal detection and passive avoidance tasks than individuals without test anxiety (Geen, 1985a, 1985b, 1987; Hagopian & Ollendick, 1994). A significant positive correlation between BIS sensitivity and nervousness, but no relationship between BAS sensitivity and nervousness, was found for a condition in which Ss anticipated punishment (Carver & White, 1994). These findings are consistent with Gray’s theory. Since the BIS and the BAS are viewed as distinct neurophysiological systems, it can be expected that activation of either the BIS or the BAS will be followed by changes in psychophysiological responses. Existing data suggest that when individuals respond actively to impending aversive cues there is an increase in heart rate (HR), while passive acceptance of impending aversive cues produces no change in HR (Obrist, 1976). Data also indicate that HR increases in response to rewards (see Fowles, 1980). Based on these findings, as well as the cardiac-somatic coupling hypothesis, Fowles (1980) has argued that HR is more strongly associated with BAS activity than BIS activity. Indirect support for this view comes from studies which have shown higher HR among highly impulsive individuals (e.g. psychopaths) compared with low impulsive individuals (see Hare, 1978 for a review). Although the data is equivocal, Fowles (1980) has also raised the possibility that electrodermal activity reflects emotional reactions to anticipation of punishment, and to that extent, it provides an index of BIS activity. The evidence of lower electrodermal activity to aversive stimuli (see Fowles, 1980), and lower electrodermal activity in high impulsive individuals compared with low impulsive individuals (see Hare, 1978 for a review) when faced with impending punishment, support this view. Overall, therefore, based on Gray’s theory, it can be argued that punishment cues will activate the BIS, which in turn will inhibit responses and at the same time produce feelings of anxiety, fear, frustration, and sadness. Reward cues will activate the BAS and produce more responses, particularly more disinhibitory responses, and feelings of happiness, hope and elation. As noted, BIS activation (and therefore punishment) has been linked to increased electrodermal activity, while BAS activation (and therefore reward) has been linked to higher HR. As the BIS and BAS are believed to be balanced in normal individuals (Gray, 1981), it can be expected that in normal individuals, punishment will activate the BIS, which in turn will lead to fewer disinhibitory responses, more negative emotions, and higher electrodermal activity. In contrast, rewards will activate the BAS, and its activation will lead to more disinhibitory responses, positive emotions and higher HR. To date, no study has obtained concurrent data on response disinhibition, emotions,
Gray’s BAS/BIS theory
307
electrodermal activity and HR in response to punishment (BIS activation) and reward (BAS activation). This study examined the differential effects of punishment and reward on the response disinhibition, HR, skin conductance level (SCL), and positive (happy) and negative (nervous) moods of normal individuals. As disinhibitory responses, moods and psychophysiological measures were collected concurrently, the study also examined how these measures covaried with each other under these reinforcement conditions. These issues were examined during instrumental learning, involving a computerized go/no-go task. Based on Gray’s theory, we predicted: (i) that compared with the punishment group, the reward group will have more disinhibitory responses, higher HR and happy mood, and lower SCL and nervousness during performance; (ii) for the punishment group, disinhibitory responses will correlate negatively with nervous mood, SCL and trait anxiety, and there will be positive correlations between nervous mood, SCL and trait anxiety; and (iii) there will be positive correlations between disinhibitory responses, happy mood, HR and trait impulsivity for the reward group.
METHOD Subjects Ss comprised 86 students from the University of Ballarat, who responded to a notice for volunteers for this study. For all Ss, informed consent was obtained prior to the study. The Ss were divided randomly into two groups of 43 Ss: the reward group and the punishment group. There were 17 males and 26 females in the reward group, and 16 males and 27 females in the punishment group. The mean age of Ss in the reward and punishment groups were 19.82 (SD=2.74) and 20.49, respectively. This age difference between the groups was not significant [t (d.f. =85)< 1, NS]. Ss were screened for known psychological disorders, medication-use and skin allergies. Procedure,
equipment
and measures
Following consent, appointments for the laboratory sessions were given to Ss. They were instructed to refrain from eating, smoking and consuming drinks containing caffeine for at least the hour prior to the laboratory sessions. Following this, Ss were given a set of personality questionnaires for completion in their own time, with instructions to return them prior to their laboratory sessions. The set of personality questionnaires comprised the Eysenck Impulsiveness Scale (EIS; Eysenck & Eysenck, 1977), the Trait-Anxiety scale of the State-Trait Anxiety Inventory Form (STAI-T; Spielberger et al., 1983), and the BIS and BAS Scales (Carver & White, 1994). The EIS provides scores for four types of impulsiveness: impulsiveness, risk-taking, non-planning and liveliness, with a’s ranging from 0.57 to 0.86. The STAI-T has 20 items, and its c( is above 0.90. The BAS Scale measures BAS sensitivity (i.e. trait impulsivity), and comprises three subscales: reward responsiveness, drive and fun-seeking, with a’s of 0.73, 0.76 and 0.66, respectively. The BIS Scale measures BIS sensitivity (i.e. trait anxiety), and its cchas been reported to be 0.74 (Carver & White, 1994). Table 1 provides the mean and standard deviation scores and the results of the t-tests for differences between the two groups on trait impulsivity and anxiety, as measured by these personality questionnaires. As will be noticed there were no significant differences between the groups on any of the measures. For the laboratory session, Ss were tested individually. They were fitted with electrodes, and psychophysiological recordings began. Psychophysiological responses were measured using Chart 3.4 on a Macintosh LC II linked to a MacLab/8s Data Acquistion System. Recordings were made at 1 mm/set, with a sampling frequency of 200 samples/set. Two psychophysiological measures were used: an electrocardiograph integrated through a cardiotachometer to achieve a mean HR, and SCL. HR rate was recorded using pre-gelled Nikomed Ag/AgCl electrodes fitted with a standard right rib, left rib placement. An electrode placed on the left mastoid process was used as an earth reference. SCL was measured using two UFI Model 1081 FG Ag/AgCl electrodes attached to the fingertips of the first and third fingers of the Ss nondominant hand. SCL was facilitated by using EC1 Electra-Gel. The electrodes were connected to a UFI Model 2701 Bioderm Skin Conductance Meter.
308
Rapson Gomez and Suzanne McLaren Table I. Trait impulsivity
and anxiety, and BIS and BAS sensitivities: group differences
Mean scores, standard
deviations
and
Group: Mean (SD) Reward
Punishment
t-statistics (d.f. =X5)
Eysenck Impulsiveness Scale Impulsiveness Risk-taking Non-planning Liveliness Spielberger‘s STAI-Trait Form
5.50 (3.13) 5.91 (2.78) 6.70 (1.67) 3.14(1.59) 41.71 (9.31)
6.76 6.40 7.19 2.98 39.00
(3.00) (2.68) (1.44) (1.37) (10.06)
1.69
BISiBAS Scales RTS BAS: Reward responsiveness BAS: Drive BAS: Fun seekmg BAS: Total
13.90 8.35 9.69 8.14 26.19
14.31 8.30 9.69 7.69 25.69
(2.60) (1.93) (2.16) (1.80) (4.66)
(3.96) (1.88) (2.43) (2.32) (5.04)
Note: No group difference for any measure.
At 10 min after being fitted with electrodes, the Ss were asked to complete a brief mood scale. In this scale, the items measuring nervous and happy were presented with three other neutral moods (interest, surprise, and agreeable). Ss rated each mood on a seven-point interval, from “not at all” (rated 1) to “very strongly” (rated 7). Immediately after completing the mood scale, the go/no-go task was administered. The task used was a computerized go/no-go task, similar to that used by Newman and Kosson (1986). This task was presented on a green monochrome IBM monitor. There were 96 test trials, divided into eight sets of 12 trials each. Each trial consisted of one of 12 two-digit numbers, presented randomly. In each trial, each stimulus was presented until the S responded or for a maximum of 3 set, if the S did not respond. The inter-stimulus interval was 1.5 sec. Of these 12 numbers, six were ‘good’ numbers, and six were ‘bad’ numbers. Ss were instructed to learn which were ‘good’ numbers and which were ‘bad’ numbers by trial and error. Eighteen practice trials were presented before the 96 test trials. Ss in the reward group were instructed that every time they responded to a ‘good’ number or refrained from responding to a ‘bad’ number they would gain 10 cents, and that there was no loss of money for failing to respond to a ‘good’ number or for responding to a ‘bad’ number. Correct responses (responding to a ‘good’ number or not responding to a ‘bad’ number) resulted in a I-set visual feedback indicating that the S had earned 10 cents. For the punishment group, all Ss started with a bonus of $9.60. They were instructed that every time they failed to respond to a ‘good’ number or they responded to a ‘bad’ number they would lose 10 cents, and that there was no gain of money for responding to a ‘good’ number or not responding to a ‘bad’ number. Incorrect responses (not responding to a ‘good’ number or responding to a ‘bad’ number) resulted in a I-see visual feedback indicating that the S had lost 10 cents. The directions for each condition were presented to Ss on the computer screen. On completion of the go/no-go task, Ss were asked to complete the brief mood-rating scale in terms of their moods during perfo~ance of the go/no-go task. Following this, psychophysiological recordings were stopped, and Ss were informed of how much money they had earned (reward group) or had remaining (punishment group). This money was paid to them. As task performance (Matthews et al., 1990), moods (Repetti, 1993), HR (Hutt & Weidner, 1993) and SCL (Kelsey, 1991) are related to stress and/or arousal, all Ss completed the short form of the Stress Arousal Checklist (SACL; King, Burrows & Stanley, 1983) immediately prior to commencing the go/no-go task, and at the end of the task. For the latter, Ss were instructed to rate the SACL items as they applied during performance. The SACL has 10 items tapping arousal and 10 items on stress. The Cos of the arousal and stress scales are 0.86 and 0.74, respectively. For both reinforcement groups, the dependent measures of disinhibitory response were the total number of responses and errors of commission (i.e. responding to ‘bad’ numbers). Hits (i.e. responding to a ‘good’ number) were also obtained in order to examine the rate of learning. For a11 three go/no-go measures, the scores were grouped into four blocks: block 1 (set + set 2), block 2 (set
Gray’s BAS/BIS theory
309
Table 2. Stress and arousal: Mean scores, standard deviations and group differences between just prior and during performance Group:
Mean (SD)
Reward
Punishment
F-values (d.f. =
I, 84)
Stress: Before Durine
2.09 (2.54) 3.28 (3.10)
2.35 (2.53) 4.14 (3.23)
Group: 1.32 Phase: 15.19* Group x Phase: < 1
Arousal: Before During
4.28 (2.09) 4.95 (2.65)
4.40 (2.45) 4.86 (2.65)
Group: < 1 Phase: 3.21 Group x Phase: <
I
‘P
3 + set 4) block 3 (set 5 + set 6), and block 4 (set 7 + set 8). For both psychophysiological measures (HR and SCL), there were five dependent variables: average of the recordings for 5 min prior to performance (pre-performance), and average of the recordings during the first (phase I), second (phase 2) third (phase 3) and fourth (phase 4) quarters of the recordings during performance. RESULTS
Group differences for stress and arousal The initial analyses were 2 (group) x 2 (time: pre-performance/performance) repeated measures ANOVAs on the stress and arousal scores of the SACL. Table 2 shows the mean and standard deviation scores, and the results of the statistical analyses. For stress, there were no group or group x time interaction effects. The main effect for time was significant, with both groups reporting increased stress levels during task performance. The results for arousal showed no group, or time, or group x time interaction effects. Thus both groups reported similar stress and arousal levels during task performance, and both groups reported a comparable increase in stress and arousal during task performance. In view of these results, the analyses for the go/no-go task performance, moods and psychophysiological responses were conducted without controlling for performance stress and arousal levels. Group differences for go/no-go task measures The differences between the groups for hits, total number of responses and commission errors for the go/no-go task were examined using 2 (group) x 4 (blocks: 1 to 4) ANOVAs. The differences between groups for these measures within each block were examined using t-tests, while the differences between blocks for all Ss together were examined by a series of single group repeated measures ANOVAs. Table 3 shows the mean and standard deviation scores, and the results of some of the statistical analyses for hits, total number of responses, and errors of commission. As shown in Table 3, for hits, the mean scores ranged from 8.81 to 9.79, indicating no ceiling effect for the go/no-go task. A 2 (group) x 4 (blocks 1 to 4) repeated measures ANOVA indicated no significant effects for group or group x block interaction. There was a main effect for block. For all Ss together, the mean scores (SD) for blocks 1,2, 3 and 4 were 8.86 (2.19) 8.92 (2.21) 9.36 (2.34) and 9.81 (2.28), respectively. A single group repeated measures ANOVA showed no difference in hits between blocks 1 and 2 [F (d.f. = 1, 85) < 1, NS]. There was significant increase in hits from block 2 to block 3 [F (d.f.=l, 85)= 113.24, P
Rapson
310
Table 3. Total number of responses, errors of commission
Group.
Gomez and Suzanne McLaren and hits during performance and group differences
of the go/no-go
task: Mean scores, standard
deviations
Mean (SD)
Reward
Punishment
Test statistics
Total responses OVerall Block 1 Block 2 Block 3 Block 4
59.79 16.33 15.09 14.60 13.77
(11.64) (3.41) (3.60) (3.81) (3.61)
53.95 15.07 13.63 12.79 12.47
(I 1.45) (3.92) (3.44) (3.22) (2.89)
Group:
F=5.50b
Commission Overall Block I Block 2 Block 3 Block 4
23.02 7.51 6.26 5.33 3.93
(10.07) (2.33) (3.06) (3.24) (3.90)
16.81 6.16 4.63 3.35 2.67
(8.86) (2.54) (2.93) (2.82) (2.46)
Group:
F=9.22'Block: F= 56.70’ Group x Block: F< I
Group x Block: F< I
Block: F=20.18’ ,= 1.58 1= 1.93” f=2.3gh r= 1.85
errors
Hits Overall Block I Block 2
36.77 (7.01) 8.81 (2.06) 8.84 (2.09)
37.14 (8.54) 8.91 (2.33) 9.00 (2.34)
Block 3 Block 4
9.28 (2.31) 9.84 (2.09)
9.44 (2.39) 9.79 (2.46)
1=2.56~ t=2.52b rz3.02 1= 1.97b
F< 1 Block: F=9.62'Group x Block: F< I
Group:
_
Note: d.f. values for F: Group = 1, 85; Block = 3, 252; Group x Block = 3, 252. “P
[F (d.f. = 1, 85) = 5.12, PcO.051, and a similar non-significant trend from block 3 to block 4 [F(d.f.= 1, 85)=3.50, P=O.O6]. As will be noticed in Table 3, there were significant main effects for group and block, and no group x block interaction effect for errors of commission. The groups differed in total number of responses for all blocks, with the punishment group scoring lower than the reward group. The mean scores (SD) for Ss as a whole for blocks 1, 2, 3 and 4 were 6.84 (2.52) 5.44 (3.09) 4.43 (3.18), 3.30 (3.01), respectively. A single group repeated measures ANOVA showed significant decrease in commission error responses from blocks 1 to 2 [F (d.f. = 1, 85)= 17.26, Pt0.0011, blocks 2 to 3 [F (d.f.= 1, 85)=21.65, P
Table 4. Moods:
Mean
scores, standard deviations and group performance and during performance Mean score (standard during Pre-perf. Observed
differences
deviation) Adjusted
between
ANCOVA d.f. = 1, 85
Nervous: Reward group Punishment group
3.00 (1.73) 3.01 (1.57)
3.00 (1.74) 3.88 (1.41)
3.02 3.86
7.91:
HIPPY: Reward group Punishment group
4.25 (1.55) 4.56 (1.24)
3.67 (1.37) 3.00 (1.33)
3.75 3.04
10.45*
Interest: Reward group Punishment group
5.14(1.15) 5.51 (1.01)
4.93 (1.22) 4.86 (1.51)
5.03 4.76
<1
Surprise: Reward group Punishment group
2.12 (1.40) 2.56 (1.52)
2.80 (1.52) 3.05 (1.46)
2.85 2.99
<1
Agreeable: Reward group Punishment group
5.24 (1.34) 5.28 (1.32)
4.00 (I .50) 4.12(1.56)
4.01 4.10
<1
“P
pre-
Gray’s BAS/BIS theory Table 5. Heart rate and skin conductance
level: Mean scores, standard phases Group: Reward
Heart rate (bpm) Pre-performance Phase 1: Phase 2: Phase 3: Phase 4:
Skin conductance Pre-performance Phase 1: Phase 2: Phase 3: Phase 4:
311
deviations
and group differences for the four
Mean (SD) Punishment
Observed Adjusted Observed Adjusted Observed Adjusted Observed Adjusted
82.98 (12.58) 84.16 (12.55) 82.91 82.98 (12.09) 81.75 84.01 (11.96) 82.83 83.94 (11.52) 82.79
80.20 (12.17) 82.23 (11.17) 83.47 81.66 (11.04) 82.88 82.35 (11.03) 83.54 82.50 (10.85) 83.66
Observed Adjusted Observed Adjusted Observed Adjusted Observed Adjusted
3.89 (2.52) 4.07 (2.55) 3.83 4.09 (2.58) 3.85 4.22 (2.65) 3.97 4.28 (2.70) 4.03
3.42 (2.46) 3.80 (2.74) 4.03 4.09 (2.87) 4.33 4.25 (3.03) 4.50 4.40 (3.10) 4.64
ANCOVA (F) d.f.=1,85
level (pcmhof
Note: bpm= beats per minute; pmho=micro *p
1.46 5.38: 5.00* 5.93*
mho.
two groups for moods. As shown, there were no significant differences between the groups for the neutral moods of interest, surprise and agreeable. In terms of the positive mood of happy, the Ss in the reward group rated themselves higher than the Ss in the punishment group, while for the negative mood of nervous, Ss in the punishment group rated themselves higher than Ss in the reward group. A single group repeated measures ANOVA indicated differences between pre-performance and performance happy mood scores for both the reward [F(d.f. = 1,42) = 6.70, P < 0.051 and punishment [F (d.f. = 1,42) = 53.06, P
groups
Table 6 shows the intercorrelations between errors of commission, moods, and psychophysiological responses in the reward and punishment groups. The correlations in this table are
312
Rapson Gomez and Suzanne McLaren Table
6. Intercorrelations between errors of commission, moods, and chophysiological responses in the reward and punishment groups EOC
EOC HIPPY Nervous HR SCL
HIPPY
Nervous
0.06
0.19 0.01
0.02 0.09 0.09 - 0.09
0.13 0.09 0.18
-0.11 0.01
psy-
HR
SCL
-0.10 0.13 0.06
-0.05 0.05 0.06 0.18
0.12
Now EOC=error of commision; HR= heart rate; SCL=skin conductance level. Correlations above the diagonal are for the reward group, below are for the pumshment group. The overall mean HR and SCL scores during performance were used to compute correlations.
Table 7. Intercorrelations
between personality
and errors of commission, in the reward group
moods, and psychophysiological
Mood
responses
Psychophysiology
Go/No-go EOC
HIPPY
NerVOllS
HR
SCL
Eysenck Impulsiveness Scale Impulsiveness Risk-taking Non-planning Livehness Spielberger’s STAI-Trait Form
0.13 -0.02 -0.25 -0.07 0.13
0.08 0.24 -0.20 0.12 -0.15
-0.00 -0.06 0.00 -0.03 0.13
0.21 -0.04 0.07 0.14 0.20
-0.10 0.18 0.06 0.00 0.13
BIS;BAS Scales BIS BAS: Reward responsiveness BAS: Drive BAS: Fun seeking BAS: Total
-0.14 -0.09 0.14 0.06 0.06
0.06 -0.15 0.17 -0.10 -0.02
-0.20 -0.16 0.11 0.03 0.00
-0.21 -0.10 0.16 -0.19 -0.04
-0.09 0.15 0.34* -0.02 0.21
Now EOC =error of commision; HR = heart rate; SCL= skin conductance scores durmg performance were used to compute correlations. *p
level. The overall mean HR and SCL
based on mood scores and overall psychophysiological scores during performance. As will be noticed, in both groups, none of the measures correlated significantly with each other. Although not shown, there were also no significant associations when the effects of the pre-performance mood and psychophysiological scores were controlled in the appropriate analyses. There were also no significant associations between errors of commission and psychophysiological scores obtained during the four phases of task performance, both with and without controlling the appropriate preperformance scores. Relations between dependent
variables and personality
measures
in the reward andpunishment
groups
Tables 7 and 8 show the correlations of personality measures with errors of commission, moods, and psychophysiological responses in the reward and punishment groups, respectively. The correlations in these tables are based on the performance mood scores and the overall performance psychophysiological scores. BAS: Drive correlated positively with SCL in the reward group. There was no other significant correlation in either group. The nature of the correlations did not vary when the effects of the pre-performance mood and psychophysiological scores were controlled in the appropriate analyses.
DISCUSSION The results of this study for differences between the two reinforcement groups can be summarized as follows: In relation to the go/no-go task, both reward and punishment increased the number of hits with time on task, and there was no group difference in the rate of increase. For the measures of total number of responses and commission error responses, both groups decreased in responses at the same rate, but Ss in the reward group generally made more responses (both types) than the punishment group throughout task performance. In relation to moods, there were no significant
Gray’s BAS/BIS theory Table 8. Intercorrelations
313
between personality and errors of commission, in the punishment group
moods, and physiological
Mood
responses
Psychophysiology
Go/No-go EOC
HIPPY
Nervous
Eysenck Impulsiveness Scale Impulsiveness Risk-taking Non-planning Liveliness Spielberger’s STAI-Trait Form
0.11 0.06 -0.11 -0.23 0.26
-0.16 0.22 -0.05 -0.05 -0.23
BIS/BAS Scales BIS BAS: Reward responsiveness BAS: Drive BAS: Fun seeking BAS: Total
0.08 0.13 -0.01 0.03 0.06
-0.05 0.04 -0.03 -0.25 -0.10
HR
SCL
0.23 0.12 -0.11 -0.14 0.11
0.09 0.06 -0.15 -0.20 0.07
-0.04 0.07 0.15 0.09 0.08
-0.10 -0.26 -0.16 -0.21 -0.27
-0.29 0.26 0.20 0.09 0.23
-0.13 0.11 0.04 -0.04 0.05
Note: EOC= error of commision; HR= heart rate; SCL=skin conductance SCL scores during performance were used to compute correlations.
level. The overall mean HR and
differences between the groups for the neutral moods of interest, surprise and agreeable. For the positive mood of happy, both groups reported lower levels during performance compared with preperformance, but the level of happy mood of the reward group during performance was higher than the punishment group. Although there was no pre-performance difference in ratings between the groups for the negative mood of nervous, Ss in the punishment group rated this mood during performance higher than Ss in the reward group, and also higher than their own pre-performance ratings. The groups did not differ for HR. For SCL, the punishment group was higher than the reward group, and the rate of increase in SCL with time on task was higher for the punishment group than the reward group. Based on Gray’s theory, it was predicted that punishment will activate the BIS and this will lead to more inhibitory responses and higher level of nervous mood, while reward will activate the BAS, leading to more disinhibitory responses and higher level of happy mood. Thus the findings of fewer responses in the go/no-go task, especially less commission errors (i.e. less disinhibitory responses), more nervous mood during performance, and increased nervous mood from pre-performance to performance in the punishment group compared with the reward group are consistent with the predictions. Also consistent with the predictions are the findings that reward resulted in more disinhibitory responses and higher levels of happy mood compared with punishment. Overall, therefore, there was some support for Gray’s theory that punishment and reward have differential effects on behaviour, emotions (moods), and psychophysiology. These findings must be considered robust as Ss in the two groups were matched for trait impulsivity and anxiety, BAS and BIS sensitivities, and stress and arousal prior to and during performance. In addition, the absence of difference between the groups for hits implies that the differences noted for total number of responses and commission errors are unlikely to have resulted from any difference in difficulty levels between the reward and punishment versions of the go/no-go task. The findings for nervous and happy moods are consistent with Gray’s theory and the study by Carver and White (1994). They found that when Ss anticipated punishment, there was a significant positive correlation between BIS sensitivity and nervousness, but no relationship between BAS sensitivity and nervousness. In terms of happy mood, Carver and White (1994) found a significant positive correlation between BAS sensitivity and happiness, but no relationship between BIS sensitivity and happiness. Based on Gray’s theory, as well as the results of the Carver and White (1994) study, it was expected that the reward group will increase in the level of happy mood from pre-performance to performance. Although the reward group obtained higher scores than the punishment group for happiness, both groups decreased in the level of happiness from pre-performance to performance. While the decrease in happy mood for the punishment group is consistent with Gray’s theory, the decrease for the reward group was unexpected, and is not consistent with Gray’s theory. One reason for this finding may be that the pressures associated with performance of the go/no-go task may have masked positive affects experienced by Ss. Indeed the finding that both groups reported higher
314
Rapson Gomez and Suzanne McLaren
levels of stress during performance provides indirect support for this view. Another explanation may be that the reward condition used in this study may not have been strong enough to produce positive moods. Unlike the study by Carver and White (1994), which provided progressive feedback during performance of earning extra experimental participation credit points (irrespective of performance), this study rewarded Ss with 10 cents for each correct response. It may be that for students, experimental participation credit points are more powerful reinforcers than small amounts of money. A third explanation may be that the BAS may not be crucial in relation to positive moods. As Ss in the Carver and White (1994) study were asked to complete their ratings of happiness after being told that they had earned the extra experimental participation credit points, it is possible that this may have accounted for the higher happiness reported by Ss. Based on Fowles’ (1980) suggestion that HR is more strongly associated with BAS activity than BIS activity, it was expected that reward (associated with activation of the BAS) would lead to increased HR. The results in this study showed no change in HR from pre-performance to performance for either group, and no difference between the groups during performance. These findings are inconsistent with Fowles’ (1980) view] that HR reflects BAS activity more than BIS activity. However, the findings in this study need to be interpreted cautiously as it is possible that (as suggested earlier) the reward used may not have been strong enough to produce changes in BAS activation to the degree required to produce noticeable differences in HR. Indeed the findings of no change in arousal level from pre-performance to performance in both groups provides indirect support for this argument. However, the possibility that increased HR may not result from BAS activation cannot be overlooked. Indeed, a recent study also reported no change in HR in a condition involving monetary reward (Sosnowski, Nurzynska & Polec, 1991). Fowles (1980) has also suggested that electrodermal activity reflects BIS activity. Consistent with this view, results demonstrated a higher SCL, and also significant increase in SCL with time given to the task in the punishment group compared with the reward group. The findings also support existing data that show a link between impulsivity and higher electrodermal activity when faced with impending punishment (Hare, 1978). Overall, the findings that punishment resulted in lower disinhibitory responses, more negative mood, and higher SCL, while reward resulted in more disinhibitory responses and positive mood support Gray’s BAS and BIS theory. However, it must be noted that these findings can also be interpreted in terms of Eysenck’s theory (Eysenck, 1967) that links differences in learning to arousal level and arousability. According to Eysenck, high arousal leads to more learning (i.e approach), while low arousal leads to less learning (i.e. avoidant). Thus, based on Eysenck’s theory, the differences noted in the two groups can be explained in terms of the low arousal produced by the punishment, and the high arousal produced by the reward. Gray’s theory also suggests that the BIS and BAS are two separate neurophysiological systems, and that the BIS is linked to trait anxiety, while the BAS is linked to trait impulsivity. Thus it was expected that the behavioural, emotional and psychophysiological responses thought to be linked to each of the systems will be associated with each other, and with the respective personality dimensions. The results in this study failed to support this, Response disinhibition, happy mood and HR were not associated with each other in the reward condition, while response inhibition, nervous mood and SCL were not associated with each other in the punishment condition. Also, response disinhibition? happy mood and FIR were not associated with trait impulsivity; and response inhibition, nervous mood and SCL were not associated with trait anxiety. Consistent with this study, Corr, Pickering, and Gray (1995) found no association between approach behaviour and impulsivity in a reward condition, and between avoidance behaviour and anxiety in a punishment condition. Taken together, these findings raise the possibility that the neurophysiological processes of the various responses, believed to be associated within each of Gray’s behavioural systems, may be somewhat different, and that the BJS and BAS may not be linked to trait anxiety and impulsivity, respectively. These findings are inconsistent with Gray’s personality theory. The findings here are consistent with the notion that disorders with major deficits in response inhibition, such as psychopathy, delinquency, and conduct disorder are related to an overactive BAS (Quay, 1988, 1993), and that impulsivity is unlikely to be related to an underactive BIS (e.g. Gray ef al., 1983; Newman, 1987). Furthermore, as nervousness is a core symptom of anxiety, it can be argued that the increase in nervous mood from pre-perfo~ance to performance, as well as
Gray’s BAS/BIS theory
315
the higher level of nervousness in the punishment group (but not the reward group), is consistent with the view linking BIS activation to high anxiety (Geen, 1985a, 1985b, 1987; Hagopian & Ollendick, 1994). In summary, the findings in this study are consistent with Gray’s BAS and BIS theory. However there was no support for Gray’s view linking the BIS to trait anxiety, and the BAS to trait impulsivity. Corr et al. (1995) have pointed out that it cannot be assumed that the relations between personality, reinforcement, moods, behaviour and psychophysiological responses in associative and instrumental learning will be the same. Indeed their study indicates some differences. It is to be noted that although the performance of the go/no-go task required instrumental learning, the task also involved associative learning, as Ss had to learn which numbers (conditioned stimuli) predicted the reward or punishment (unconditional stimuli). Thus it is possible that the associative learning involved in performance of the go/no-go task may have influenced the findings in this study. In view of the findings of Corr et al. (1995), there is need for some caution in the conclusions drawn. Clearly more studies aimed at ‘directly’ testing Gray’s theory, as in this study, are needed. In this respect, studies using ‘pure’ associative and instrumental learning tasks, such as those used by Corr et al. (1995), will be useful. Acknowledgements-We
are grateful to Dr John Winkelman, School of Behavioural and Social Sciences and Humanities, University of Ballarat, for writing the computer program for the go/no-go task. The study was supported by a grant from the School of Behavioural and Social Sciences and Humanities, University of Ballarat.
REFERENCES Carver, C. S. & White, T. L. (1994). Behavioral inhibition, behavioral activation, and affective responses to impending reward and punishment: The BIS/BAS scales. Journal ofPersonality and Social Psychology, 67, 319-333. Corr, P. J., Pickering, A. D. & Gray, J. A. (1995). Personality and reinforcement in associative and instrumental learning. Personality
Eysenck, Eysenck,
and Individual Differences,
19, 47-7
I.
H. J. (1967). The biological basis ofpersonality. Springfield, IL: Thomas. S. & Eysenck, H. (1977). The place of impulsiveness in a dimensional system of personality
Journal
of Psychology,
description.
British
16, 57-68.
Fowles, D. C. (1980). The three arousal model: Implications of Gray’s two-factor learning theory for heart rate, electrodermal activity, and psychopathy. Psychophysiology, 17. 87-104. Geen, R. G. (1985). Evaluation apprehension and response withholding in solution of anagrams. Personality and Individual Differences,
6, 293-298.
Geen, R. G. (1985). Test anxiety and visual vigilance. Journal qf Personalityand Social Psychology, 49, 363-370. Geen, R. G. (1987). Anxiety and behavioral avoidance. Journal of Research in Personality, 21,481488. Gorenstein, E. E. & Newman, J. P. (1980). Disinhibitory psychopathology: A new perspective and a model for research. Psychologicul Review, 87, 301-315. Gray, J. A. (1970). The psychophysiological basis of introversion%xtraversion. Behavior Research and Therapy, 8,249-266. Gray, J. A. (1981). A critique of Eysenck’s theory of personality. In H. J. Eysenck (Ed.), A modelfor personality (pp. 246 276). New York: Springer. Gray, J. A. (1982). The neuropsychology of anxiety. New York: Oxford University Press. Gray, J. A. (1987). The psychology offear and stress (2nd edn). Cambridge, England: Cambridge University Press. Gray, J. A. (1990). Brain systems that mediate both emotion and cognition. Cognition and Emotion, 4, 269-288. Gray, J. A., Owen, S., Davis, N. & Tsaltas, E. (1983). Psychological and physiological relations between anxiety and impulsivity. In M. Zuckerman (Ed.), Biological bases qfsensation seeking, impulsioity and anxiety (pp. 18 l-217). Hillsdale, NJ: Erlbaum. Hagopian, L. P. & Ollendick, T. H. (1994). Behavioral inhibition and test anxiety: An empirical investigation of Gray’s theory. Personality and Indiuiduul Difflences, 16, 597-604. Hare, R. D. (1978). Electrodermal and cardiovascular correlates of psychopathy. In R. D. Hare & D. Schalling (Eds), Psychopathic behavior: Approaches to research (pp. 107-144). New York: Wiley. Hutt, J. & Weidner, G. (1993). The effects of task demand and decision latitude on cardiovascular reactivity to stress. Behavioral
Medicine,
18, 181L188.
Kelsey, R. M. (1991). Electrodermal lability and myocardial reactivity to stress. Psychophysiology, 28, 619431. King, M. G., Burrows, G. D. & Stanley, G. V. (1983). Measurement of stress and arousal: Validation of the stress/arousal checklist. British Journal of Psychology, 74, 413479. Matthews, G., Davies, D. R. & Lees, J. L. (1990). Arousal, extraversion, and individual differences in resource availability. Journal
of Personalit),
and Social Psychology,
59, 150-l 68.
McCleary, R. A. (1966). Response modulating function of the limbic system: Initiation and suppression. In E. Stellar & J. M. Sprague (Eds), Progress in physiologicalpsychology (Vol. I, pp. 209-271). San Diego, CA: Academic Press. Newman, J. P. (1987). Reaction to punishment in extraverts and psychopaths: Implications for the impulsive behavior of disinhibited individuals. Journal of Research in Personality, 21, 464-480. Newman, J. P. & Kosson, D. S. (1986). Passive avoidance learning in psychopathic and nonpsychopathic offenders. Journal of Abnormal
Newman,
Psychology,
J. P., Patterson,
Psychology,
96, 145-148.
96, 145-148.
C. M. & Kosson,
D. S. (1987). Response
perseveration
in psychopaths.
Journal
of Abnormal
316
Rapson
Gomez and Suzanne
McLaren
Newman, J. P., Widom, C. S. & Nathan, S. (1985). Passive avoidance in syndromes of disinhibition: Psychopathy and extraversion. Journal of Personality and Social Psychology, 48, 1316-l 327. Obrist, P. A. (1976). The cardiovascular-behavioral interaction as it appears today. Psychophysiology, 1.3, 95-107. Patterson, C. M. & Newman, J. P. (1993). Reflectivity and learning from aversive events: Toward a psychological mechanism for the syndromes of disinhibition. Psychological Review, 100, 716736. Quay, H. C. (1988). The behavioral reward and inhibition system in childhood behavior disorders. In L. M. Bloomingdale (Ed.), Attention de&it disorder (Vol. 3, pp. 176186). Oxford: Pergamon Press. Quay, H. C. (1993). The psychobiology of undersocialized aggressive conduct disorder: A theoretical perspective. Development and Psychopathology, 5, 1655180. Repetti, R. L. (1993). Short-term effects of occupational stressors on daily mood and health complaints. Health Psychology, 12, 125-131. Sosnowski, T., Nurzynska, M. & Polec, M. (1991). Active-passive coping and skin conductance and heart rate changes. Psychophysiology, 28, 665-672. Spielberger, C. D., Gorsuch, R., Lushene, R., Vagg. P. R. & Jacobs, G. A. (1983). Manual for the Stak~Trait AnxiefJ Inventory (Form r). Palo Alto, CA: Consulting Psychologists Press.
Person. indirid. D# Vol. 23, No. 2, pp. 305-316, 1997 CI1997 Elsevier Science Ltd. All rights reserved Printed in Great Britain 0191.8869/97 $17.00+0.00 SO191-8869(97)00031-7
THE EFFECTS OF REWARD AND PUNISHMENT ON RESPONSE DISINHIBITION, MOODS, HEART RATE AND SKIN CONDUCTANCE LEVEL DURING INSTRUMENTAL LEARNING Rapson School of Behavioural
Gomez*
and Suzanne
McLaren
and Social Sciences and Humanities, University Ballarat, 3350, Victoria, Australia (Received
9 September
of Ballarat,
Gear Avenue,
I!&%/
Summary-The study examined the effects of reward and punishment on response disinhibition, happy and nervous moods, heart rate and skin conductance levels during performance of an instrumental learning task. For one group of subjects (the reward group), correct responses were reinforced with a small monetary reward, while for another group (the punishment group), incorrect responses led to a small loss of money. Results indicated that subjects in the punishment group made fewer disinhibitory responses, were more nervous and less happy, and had a higher skin conductance level compared with subjects in the reward group. For both groups, these measures (and heart rate) did not correlate with each other, or with trait impulsivity or trait anxiety. These findings are discussed in relation to Gray’s theory of behavioural inhibition system (BIS) and behavioural approach system (BAS). c] 1997 Elsevier Science Ltd
INTRODUCTION
Eysenck’s (1967) theory of personality suggests two orthogonally related neurological based dimensions of personality: Extraversion-Introversion and NeuroticismPStability. J. A. Gray (1970) also proposed two orthogonal dimensions of personality, these being Anxiety and Impulsivity. In relating his own theory to that of Eysenck’s, Gray (1970, 1987) has proposed that in terms of a twodimensional space defined by Extraversion-Introversion and Neuroticism-Stability, the anxiety axis runs from the stable-extravert quadrant to the neurotic-introvert quadrant, while the impulsivity axis runs from the stable-introvert quadrant to the neurotic-extravert quadrant. On the anxiety axis, high anxious individuals are in the neurotic introvert quadrant and low anxious individuals are in the stable extravert quadrant. In terms of the impulsivity axis, high impulsive individuals are in the neurotic extravert quadrant, while low impulsive individuals are in the stable introvert quadrant. Based on animal learning, pharmacological and lesion studies, Gray (1970, 1981, 1990) has proposed that the anxiety and impulsivity dimensions of personality reflect two structurally distinct neurophysiological systems that differ in their sensitivities to reward and punishment cues. The neural substrates of anxiety were referred to as the behavioural inhibition system (BIS), while those related to impulsivity were referred to as the behavioural approach system (BAS). According to Gray (1982), the neural substrates of the BIS are the septohippocampal systems, including the monoaminergic afferents from the brainstem and the neocortical projection to the frontal lobe, while the neurological substrates of the BAS are the catecholaminergic (especially dopaminergic) pathways to the mesolimbic system. Gray’s (1970, 1990) theory suggests that activation of the BIS and the BAS lead to different behaviours and emotions. In relation to behaviour, this theory suggests that the BIS is sensitive to signals of punishment, frustrative non-reward and novelty, and when it is activated by such signals, it inhibits behaviour that will lead to further negative or painful outcomes. In contrast, the BAS is believed to be sensitive to signals of reward and non-punishment, and when it is activated by such signals, it causes or increases behaviour toward more rewards or goals. Thus, the BIS is activated by punishment, and is involved in regulating aversive motivation. The BAS is activated by reward, and is involved in regulating appetitive motivation. In terms of emotions, Gray (1990) has suggested
*To whom all correspondence
should be addressed. 305
306
Rapson Gomez and Suzanne McLaren
that activation of the BIS leads to negative affects such as anxiety, fear, frustration, and sadness, while activation of the BAS leads to positive affects such as happiness, hope, and elation. As pointed out earlier, Gray’s theory was developed primarily on animal studies. In recent years researchers have begun examining hypotheses derived from Gray’s theory with human Ss (e.g. Carver & White, 1994; Geen, 1987; Hagopian & Ollendick, 1994; Newman, Patterson & Kosson, 1987). Several studies have evaluated the activity of the BAS in relation to response disinhibition using response perseveration and passive avoidance learning paradigms (e.g. Gorenstein & Newman, 1980; Patterson & Newman, 1993). Perseveration refers to an exaggerated tendency to emit a dominant response despite punishment (McCleary, 1966) while passive avoidance learning refers to withholding a response (often an appetitively motivated one) to avoid punishment by learning cues that predict it (Patterson & Newman, 1993). Evidence suggests that when both reward and punishment are present, disinhibited individuals (such as psychopath adults and delinquent adolescents) exhibit more perseverative responses (Gorenstein & Newman, 1980; Newman et al., 1987) and more commission error responses (an index of response disinhibition) on passive avoidance learning tasks (Newman & Kosson, 1986; Newman, Widom & Nathan, 1985) than controls. There is also evidence that college students grouped as ‘neurotic extravert’ (individuals with high BAS sensitivity) obtained more errors of commission on a passive avoidance discrimination task in the presence of reward cues than when only punishment cues were present (Newman, 1987). These findings suggest that for impulsive individuals, the BAS is more sensitive than the BIS when rewards are present. This interpretation is consistent with Gray’s theory. In general, these studies provide indirect support for Gray’s theory. In relation to emotions, Carver and White (1994) reported that when Ss anticipated rewards, a significant positive correlation between BAS sensitivity and happiness was found, but there was no relationship between BIS sensitivity and happiness. Studies that have examined the BIS have demonstrated that individuals with high test anxiety made fewer impulsive responses on signal detection and passive avoidance tasks than individuals without test anxiety (Geen, 1985a, 1985b, 1987; Hagopian & Ollendick, 1994). A significant positive correlation between BIS sensitivity and nervousness, but no relationship between BAS sensitivity and nervousness, was found for a condition in which Ss anticipated punishment (Carver & White, 1994). These findings are consistent with Gray’s theory. Since the BIS and the BAS are viewed as distinct neurophysiological systems, it can be expected that activation of either the BIS or the BAS will be followed by changes in psychophysiological responses. Existing data suggest that when individuals respond actively to impending aversive cues there is an increase in heart rate (HR), while passive acceptance of impending aversive cues produces no change in HR (Obrist, 1976). Data also indicate that HR increases in response to rewards (see Fowles, 1980). Based on these findings, as well as the cardiac-somatic coupling hypothesis, Fowles (1980) has argued that HR is more strongly associated with BAS activity than BIS activity. Indirect support for this view comes from studies which have shown higher HR among highly impulsive individuals (e.g. psychopaths) compared with low impulsive individuals (see Hare, 1978 for a review). Although the data is equivocal, Fowles (1980) has also raised the possibility that electrodermal activity reflects emotional reactions to anticipation of punishment, and to that extent, it provides an index of BIS activity. The evidence of lower electrodermal activity to aversive stimuli (see Fowles, 1980), and lower electrodermal activity in high impulsive individuals compared with low impulsive individuals (see Hare, 1978 for a review) when faced with impending punishment, support this view. Overall, therefore, based on Gray’s theory, it can be argued that punishment cues will activate the BIS, which in turn will inhibit responses and at the same time produce feelings of anxiety, fear, frustration, and sadness. Reward cues will activate the BAS and produce more responses, particularly more disinhibitory responses, and feelings of happiness, hope and elation. As noted, BIS activation (and therefore punishment) has been linked to increased electrodermal activity, while BAS activation (and therefore reward) has been linked to higher HR. As the BIS and BAS are believed to be balanced in normal individuals (Gray, 1981), it can be expected that in normal individuals, punishment will activate the BIS, which in turn will lead to fewer disinhibitory responses, more negative emotions, and higher electrodermal activity. In contrast, rewards will activate the BAS, and its activation will lead to more disinhibitory responses, positive emotions and higher HR. To date, no study has obtained concurrent data on response disinhibition, emotions,
Gray’s BAS/BIS theory
307
electrodermal activity and HR in response to punishment (BIS activation) and reward (BAS activation). This study examined the differential effects of punishment and reward on the response disinhibition, HR, skin conductance level (SCL), and positive (happy) and negative (nervous) moods of normal individuals. As disinhibitory responses, moods and psychophysiological measures were collected concurrently, the study also examined how these measures covaried with each other under these reinforcement conditions. These issues were examined during instrumental learning, involving a computerized go/no-go task. Based on Gray’s theory, we predicted: (i) that compared with the punishment group, the reward group will have more disinhibitory responses, higher HR and happy mood, and lower SCL and nervousness during performance; (ii) for the punishment group, disinhibitory responses will correlate negatively with nervous mood, SCL and trait anxiety, and there will be positive correlations between nervous mood, SCL and trait anxiety; and (iii) there will be positive correlations between disinhibitory responses, happy mood, HR and trait impulsivity for the reward group.
METHOD Subjects Ss comprised 86 students from the University of Ballarat, who responded to a notice for volunteers for this study. For all Ss, informed consent was obtained prior to the study. The Ss were divided randomly into two groups of 43 Ss: the reward group and the punishment group. There were 17 males and 26 females in the reward group, and 16 males and 27 females in the punishment group. The mean age of Ss in the reward and punishment groups were 19.82 (SD=2.74) and 20.49, respectively. This age difference between the groups was not significant [t (d.f. =85)< 1, NS]. Ss were screened for known psychological disorders, medication-use and skin allergies. Procedure,
equipment
and measures
Following consent, appointments for the laboratory sessions were given to Ss. They were instructed to refrain from eating, smoking and consuming drinks containing caffeine for at least the hour prior to the laboratory sessions. Following this, Ss were given a set of personality questionnaires for completion in their own time, with instructions to return them prior to their laboratory sessions. The set of personality questionnaires comprised the Eysenck Impulsiveness Scale (EIS; Eysenck & Eysenck, 1977), the Trait-Anxiety scale of the State-Trait Anxiety Inventory Form (STAI-T; Spielberger et al., 1983), and the BIS and BAS Scales (Carver & White, 1994). The EIS provides scores for four types of impulsiveness: impulsiveness, risk-taking, non-planning and liveliness, with a’s ranging from 0.57 to 0.86. The STAI-T has 20 items, and its c( is above 0.90. The BAS Scale measures BAS sensitivity (i.e. trait impulsivity), and comprises three subscales: reward responsiveness, drive and fun-seeking, with a’s of 0.73, 0.76 and 0.66, respectively. The BIS Scale measures BIS sensitivity (i.e. trait anxiety), and its cchas been reported to be 0.74 (Carver & White, 1994). Table 1 provides the mean and standard deviation scores and the results of the t-tests for differences between the two groups on trait impulsivity and anxiety, as measured by these personality questionnaires. As will be noticed there were no significant differences between the groups on any of the measures. For the laboratory session, Ss were tested individually. They were fitted with electrodes, and psychophysiological recordings began. Psychophysiological responses were measured using Chart 3.4 on a Macintosh LC II linked to a MacLab/8s Data Acquistion System. Recordings were made at 1 mm/set, with a sampling frequency of 200 samples/set. Two psychophysiological measures were used: an electrocardiograph integrated through a cardiotachometer to achieve a mean HR, and SCL. HR rate was recorded using pre-gelled Nikomed Ag/AgCl electrodes fitted with a standard right rib, left rib placement. An electrode placed on the left mastoid process was used as an earth reference. SCL was measured using two UFI Model 1081 FG Ag/AgCl electrodes attached to the fingertips of the first and third fingers of the Ss nondominant hand. SCL was facilitated by using EC1 Electra-Gel. The electrodes were connected to a UFI Model 2701 Bioderm Skin Conductance Meter.
308
Rapson Gomez and Suzanne McLaren Table I. Trait impulsivity
and anxiety, and BIS and BAS sensitivities: group differences
Mean scores, standard
deviations
and
Group: Mean (SD) Reward
Punishment
t-statistics (d.f. =X5)
Eysenck Impulsiveness Scale Impulsiveness Risk-taking Non-planning Liveliness Spielberger‘s STAI-Trait Form
5.50 (3.13) 5.91 (2.78) 6.70 (1.67) 3.14(1.59) 41.71 (9.31)
6.76 6.40 7.19 2.98 39.00
(3.00) (2.68) (1.44) (1.37) (10.06)
1.69
BISiBAS Scales RTS BAS: Reward responsiveness BAS: Drive BAS: Fun seekmg BAS: Total
13.90 8.35 9.69 8.14 26.19
14.31 8.30 9.69 7.69 25.69
(2.60) (1.93) (2.16) (1.80) (4.66)
(3.96) (1.88) (2.43) (2.32) (5.04)
Note: No group difference for any measure.
At 10 min after being fitted with electrodes, the Ss were asked to complete a brief mood scale. In this scale, the items measuring nervous and happy were presented with three other neutral moods (interest, surprise, and agreeable). Ss rated each mood on a seven-point interval, from “not at all” (rated 1) to “very strongly” (rated 7). Immediately after completing the mood scale, the go/no-go task was administered. The task used was a computerized go/no-go task, similar to that used by Newman and Kosson (1986). This task was presented on a green monochrome IBM monitor. There were 96 test trials, divided into eight sets of 12 trials each. Each trial consisted of one of 12 two-digit numbers, presented randomly. In each trial, each stimulus was presented until the S responded or for a maximum of 3 set, if the S did not respond. The inter-stimulus interval was 1.5 sec. Of these 12 numbers, six were ‘good’ numbers, and six were ‘bad’ numbers. Ss were instructed to learn which were ‘good’ numbers and which were ‘bad’ numbers by trial and error. Eighteen practice trials were presented before the 96 test trials. Ss in the reward group were instructed that every time they responded to a ‘good’ number or refrained from responding to a ‘bad’ number they would gain 10 cents, and that there was no loss of money for failing to respond to a ‘good’ number or for responding to a ‘bad’ number. Correct responses (responding to a ‘good’ number or not responding to a ‘bad’ number) resulted in a I-set visual feedback indicating that the S had earned 10 cents. For the punishment group, all Ss started with a bonus of $9.60. They were instructed that every time they failed to respond to a ‘good’ number or they responded to a ‘bad’ number they would lose 10 cents, and that there was no gain of money for responding to a ‘good’ number or not responding to a ‘bad’ number. Incorrect responses (not responding to a ‘good’ number or responding to a ‘bad’ number) resulted in a I-see visual feedback indicating that the S had lost 10 cents. The directions for each condition were presented to Ss on the computer screen. On completion of the go/no-go task, Ss were asked to complete the brief mood-rating scale in terms of their moods during perfo~ance of the go/no-go task. Following this, psychophysiological recordings were stopped, and Ss were informed of how much money they had earned (reward group) or had remaining (punishment group). This money was paid to them. As task performance (Matthews et al., 1990), moods (Repetti, 1993), HR (Hutt & Weidner, 1993) and SCL (Kelsey, 1991) are related to stress and/or arousal, all Ss completed the short form of the Stress Arousal Checklist (SACL; King, Burrows & Stanley, 1983) immediately prior to commencing the go/no-go task, and at the end of the task. For the latter, Ss were instructed to rate the SACL items as they applied during performance. The SACL has 10 items tapping arousal and 10 items on stress. The Cos of the arousal and stress scales are 0.86 and 0.74, respectively. For both reinforcement groups, the dependent measures of disinhibitory response were the total number of responses and errors of commission (i.e. responding to ‘bad’ numbers). Hits (i.e. responding to a ‘good’ number) were also obtained in order to examine the rate of learning. For a11 three go/no-go measures, the scores were grouped into four blocks: block 1 (set + set 2), block 2 (set
Gray’s BAS/BIS theory
309
Table 2. Stress and arousal: Mean scores, standard deviations and group differences between just prior and during performance Group:
Mean (SD)
Reward
Punishment
F-values (d.f. =
I, 84)
Stress: Before Durine
2.09 (2.54) 3.28 (3.10)
2.35 (2.53) 4.14 (3.23)
Group: 1.32 Phase: 15.19* Group x Phase: < 1
Arousal: Before During
4.28 (2.09) 4.95 (2.65)
4.40 (2.45) 4.86 (2.65)
Group: < 1 Phase: 3.21 Group x Phase: <
I
‘P
3 + set 4) block 3 (set 5 + set 6), and block 4 (set 7 + set 8). For both psychophysiological measures (HR and SCL), there were five dependent variables: average of the recordings for 5 min prior to performance (pre-performance), and average of the recordings during the first (phase I), second (phase 2) third (phase 3) and fourth (phase 4) quarters of the recordings during performance. RESULTS
Group differences for stress and arousal The initial analyses were 2 (group) x 2 (time: pre-performance/performance) repeated measures ANOVAs on the stress and arousal scores of the SACL. Table 2 shows the mean and standard deviation scores, and the results of the statistical analyses. For stress, there were no group or group x time interaction effects. The main effect for time was significant, with both groups reporting increased stress levels during task performance. The results for arousal showed no group, or time, or group x time interaction effects. Thus both groups reported similar stress and arousal levels during task performance, and both groups reported a comparable increase in stress and arousal during task performance. In view of these results, the analyses for the go/no-go task performance, moods and psychophysiological responses were conducted without controlling for performance stress and arousal levels. Group differences for go/no-go task measures The differences between the groups for hits, total number of responses and commission errors for the go/no-go task were examined using 2 (group) x 4 (blocks: 1 to 4) ANOVAs. The differences between groups for these measures within each block were examined using t-tests, while the differences between blocks for all Ss together were examined by a series of single group repeated measures ANOVAs. Table 3 shows the mean and standard deviation scores, and the results of some of the statistical analyses for hits, total number of responses, and errors of commission. As shown in Table 3, for hits, the mean scores ranged from 8.81 to 9.79, indicating no ceiling effect for the go/no-go task. A 2 (group) x 4 (blocks 1 to 4) repeated measures ANOVA indicated no significant effects for group or group x block interaction. There was a main effect for block. For all Ss together, the mean scores (SD) for blocks 1,2, 3 and 4 were 8.86 (2.19) 8.92 (2.21) 9.36 (2.34) and 9.81 (2.28), respectively. A single group repeated measures ANOVA showed no difference in hits between blocks 1 and 2 [F (d.f. = 1, 85) < 1, NS]. There was significant increase in hits from block 2 to block 3 [F (d.f.=l, 85)= 113.24, P
Rapson
310
Table 3. Total number of responses, errors of commission
Group.
Gomez and Suzanne McLaren and hits during performance and group differences
of the go/no-go
task: Mean scores, standard
deviations
Mean (SD)
Reward
Punishment
Test statistics
Total responses OVerall Block 1 Block 2 Block 3 Block 4
59.79 16.33 15.09 14.60 13.77
(11.64) (3.41) (3.60) (3.81) (3.61)
53.95 15.07 13.63 12.79 12.47
(I 1.45) (3.92) (3.44) (3.22) (2.89)
Group:
F=5.50b
Commission Overall Block I Block 2 Block 3 Block 4
23.02 7.51 6.26 5.33 3.93
(10.07) (2.33) (3.06) (3.24) (3.90)
16.81 6.16 4.63 3.35 2.67
(8.86) (2.54) (2.93) (2.82) (2.46)
Group:
F=9.22'Block: F= 56.70’ Group x Block: F< I
Group x Block: F< I
Block: F=20.18’ ,= 1.58 1= 1.93” f=2.3gh r= 1.85
errors
Hits Overall Block I Block 2
36.77 (7.01) 8.81 (2.06) 8.84 (2.09)
37.14 (8.54) 8.91 (2.33) 9.00 (2.34)
Block 3 Block 4
9.28 (2.31) 9.84 (2.09)
9.44 (2.39) 9.79 (2.46)
1=2.56~ t=2.52b rz3.02 1= 1.97b
F< 1 Block: F=9.62'Group x Block: F< I
Group:
_
Note: d.f. values for F: Group = 1, 85; Block = 3, 252; Group x Block = 3, 252. “P
[F (d.f. = 1, 85) = 5.12, PcO.051, and a similar non-significant trend from block 3 to block 4 [F(d.f.= 1, 85)=3.50, P=O.O6]. As will be noticed in Table 3, there were significant main effects for group and block, and no group x block interaction effect for errors of commission. The groups differed in total number of responses for all blocks, with the punishment group scoring lower than the reward group. The mean scores (SD) for Ss as a whole for blocks 1, 2, 3 and 4 were 6.84 (2.52) 5.44 (3.09) 4.43 (3.18), 3.30 (3.01), respectively. A single group repeated measures ANOVA showed significant decrease in commission error responses from blocks 1 to 2 [F (d.f. = 1, 85)= 17.26, Pt0.0011, blocks 2 to 3 [F (d.f.= 1, 85)=21.65, P
Table 4. Moods:
Mean
scores, standard deviations and group performance and during performance Mean score (standard during Pre-perf. Observed
differences
deviation) Adjusted
between
ANCOVA d.f. = 1, 85
Nervous: Reward group Punishment group
3.00 (1.73) 3.01 (1.57)
3.00 (1.74) 3.88 (1.41)
3.02 3.86
7.91:
HIPPY: Reward group Punishment group
4.25 (1.55) 4.56 (1.24)
3.67 (1.37) 3.00 (1.33)
3.75 3.04
10.45*
Interest: Reward group Punishment group
5.14(1.15) 5.51 (1.01)
4.93 (1.22) 4.86 (1.51)
5.03 4.76
<1
Surprise: Reward group Punishment group
2.12 (1.40) 2.56 (1.52)
2.80 (1.52) 3.05 (1.46)
2.85 2.99
<1
Agreeable: Reward group Punishment group
5.24 (1.34) 5.28 (1.32)
4.00 (I .50) 4.12(1.56)
4.01 4.10
<1
“P
pre-
Gray’s BAS/BIS theory Table 5. Heart rate and skin conductance
level: Mean scores, standard phases Group: Reward
Heart rate (bpm) Pre-performance Phase 1: Phase 2: Phase 3: Phase 4:
Skin conductance Pre-performance Phase 1: Phase 2: Phase 3: Phase 4:
311
deviations
and group differences for the four
Mean (SD) Punishment
Observed Adjusted Observed Adjusted Observed Adjusted Observed Adjusted
82.98 (12.58) 84.16 (12.55) 82.91 82.98 (12.09) 81.75 84.01 (11.96) 82.83 83.94 (11.52) 82.79
80.20 (12.17) 82.23 (11.17) 83.47 81.66 (11.04) 82.88 82.35 (11.03) 83.54 82.50 (10.85) 83.66
Observed Adjusted Observed Adjusted Observed Adjusted Observed Adjusted
3.89 (2.52) 4.07 (2.55) 3.83 4.09 (2.58) 3.85 4.22 (2.65) 3.97 4.28 (2.70) 4.03
3.42 (2.46) 3.80 (2.74) 4.03 4.09 (2.87) 4.33 4.25 (3.03) 4.50 4.40 (3.10) 4.64
ANCOVA (F) d.f.=1,85
level (pcmhof
Note: bpm= beats per minute; pmho=micro *p
1.46 5.38: 5.00* 5.93*
mho.
two groups for moods. As shown, there were no significant differences between the groups for the neutral moods of interest, surprise and agreeable. In terms of the positive mood of happy, the Ss in the reward group rated themselves higher than the Ss in the punishment group, while for the negative mood of nervous, Ss in the punishment group rated themselves higher than Ss in the reward group. A single group repeated measures ANOVA indicated differences between pre-performance and performance happy mood scores for both the reward [F(d.f. = 1,42) = 6.70, P < 0.051 and punishment [F (d.f. = 1,42) = 53.06, P
groups
Table 6 shows the intercorrelations between errors of commission, moods, and psychophysiological responses in the reward and punishment groups. The correlations in this table are
312
Rapson Gomez and Suzanne McLaren Table
6. Intercorrelations between errors of commission, moods, and chophysiological responses in the reward and punishment groups EOC
EOC HIPPY Nervous HR SCL
HIPPY
Nervous
0.06
0.19 0.01
0.02 0.09 0.09 - 0.09
0.13 0.09 0.18
-0.11 0.01
psy-
HR
SCL
-0.10 0.13 0.06
-0.05 0.05 0.06 0.18
0.12
Now EOC=error of commision; HR= heart rate; SCL=skin conductance level. Correlations above the diagonal are for the reward group, below are for the pumshment group. The overall mean HR and SCL scores during performance were used to compute correlations.
Table 7. Intercorrelations
between personality
and errors of commission, in the reward group
moods, and psychophysiological
Mood
responses
Psychophysiology
Go/No-go EOC
HIPPY
NerVOllS
HR
SCL
Eysenck Impulsiveness Scale Impulsiveness Risk-taking Non-planning Livehness Spielberger’s STAI-Trait Form
0.13 -0.02 -0.25 -0.07 0.13
0.08 0.24 -0.20 0.12 -0.15
-0.00 -0.06 0.00 -0.03 0.13
0.21 -0.04 0.07 0.14 0.20
-0.10 0.18 0.06 0.00 0.13
BIS;BAS Scales BIS BAS: Reward responsiveness BAS: Drive BAS: Fun seeking BAS: Total
-0.14 -0.09 0.14 0.06 0.06
0.06 -0.15 0.17 -0.10 -0.02
-0.20 -0.16 0.11 0.03 0.00
-0.21 -0.10 0.16 -0.19 -0.04
-0.09 0.15 0.34* -0.02 0.21
Now EOC =error of commision; HR = heart rate; SCL= skin conductance scores durmg performance were used to compute correlations. *p
level. The overall mean HR and SCL
based on mood scores and overall psychophysiological scores during performance. As will be noticed, in both groups, none of the measures correlated significantly with each other. Although not shown, there were also no significant associations when the effects of the pre-performance mood and psychophysiological scores were controlled in the appropriate analyses. There were also no significant associations between errors of commission and psychophysiological scores obtained during the four phases of task performance, both with and without controlling the appropriate preperformance scores. Relations between dependent
variables and personality
measures
in the reward andpunishment
groups
Tables 7 and 8 show the correlations of personality measures with errors of commission, moods, and psychophysiological responses in the reward and punishment groups, respectively. The correlations in these tables are based on the performance mood scores and the overall performance psychophysiological scores. BAS: Drive correlated positively with SCL in the reward group. There was no other significant correlation in either group. The nature of the correlations did not vary when the effects of the pre-performance mood and psychophysiological scores were controlled in the appropriate analyses.
DISCUSSION The results of this study for differences between the two reinforcement groups can be summarized as follows: In relation to the go/no-go task, both reward and punishment increased the number of hits with time on task, and there was no group difference in the rate of increase. For the measures of total number of responses and commission error responses, both groups decreased in responses at the same rate, but Ss in the reward group generally made more responses (both types) than the punishment group throughout task performance. In relation to moods, there were no significant
Gray’s BAS/BIS theory Table 8. Intercorrelations
313
between personality and errors of commission, in the punishment group
moods, and physiological
Mood
responses
Psychophysiology
Go/No-go EOC
HIPPY
Nervous
Eysenck Impulsiveness Scale Impulsiveness Risk-taking Non-planning Liveliness Spielberger’s STAI-Trait Form
0.11 0.06 -0.11 -0.23 0.26
-0.16 0.22 -0.05 -0.05 -0.23
BIS/BAS Scales BIS BAS: Reward responsiveness BAS: Drive BAS: Fun seeking BAS: Total
0.08 0.13 -0.01 0.03 0.06
-0.05 0.04 -0.03 -0.25 -0.10
HR
SCL
0.23 0.12 -0.11 -0.14 0.11
0.09 0.06 -0.15 -0.20 0.07
-0.04 0.07 0.15 0.09 0.08
-0.10 -0.26 -0.16 -0.21 -0.27
-0.29 0.26 0.20 0.09 0.23
-0.13 0.11 0.04 -0.04 0.05
Note: EOC= error of commision; HR= heart rate; SCL=skin conductance SCL scores during performance were used to compute correlations.
level. The overall mean HR and
differences between the groups for the neutral moods of interest, surprise and agreeable. For the positive mood of happy, both groups reported lower levels during performance compared with preperformance, but the level of happy mood of the reward group during performance was higher than the punishment group. Although there was no pre-performance difference in ratings between the groups for the negative mood of nervous, Ss in the punishment group rated this mood during performance higher than Ss in the reward group, and also higher than their own pre-performance ratings. The groups did not differ for HR. For SCL, the punishment group was higher than the reward group, and the rate of increase in SCL with time on task was higher for the punishment group than the reward group. Based on Gray’s theory, it was predicted that punishment will activate the BIS and this will lead to more inhibitory responses and higher level of nervous mood, while reward will activate the BAS, leading to more disinhibitory responses and higher level of happy mood. Thus the findings of fewer responses in the go/no-go task, especially less commission errors (i.e. less disinhibitory responses), more nervous mood during performance, and increased nervous mood from pre-performance to performance in the punishment group compared with the reward group are consistent with the predictions. Also consistent with the predictions are the findings that reward resulted in more disinhibitory responses and higher levels of happy mood compared with punishment. Overall, therefore, there was some support for Gray’s theory that punishment and reward have differential effects on behaviour, emotions (moods), and psychophysiology. These findings must be considered robust as Ss in the two groups were matched for trait impulsivity and anxiety, BAS and BIS sensitivities, and stress and arousal prior to and during performance. In addition, the absence of difference between the groups for hits implies that the differences noted for total number of responses and commission errors are unlikely to have resulted from any difference in difficulty levels between the reward and punishment versions of the go/no-go task. The findings for nervous and happy moods are consistent with Gray’s theory and the study by Carver and White (1994). They found that when Ss anticipated punishment, there was a significant positive correlation between BIS sensitivity and nervousness, but no relationship between BAS sensitivity and nervousness. In terms of happy mood, Carver and White (1994) found a significant positive correlation between BAS sensitivity and happiness, but no relationship between BIS sensitivity and happiness. Based on Gray’s theory, as well as the results of the Carver and White (1994) study, it was expected that the reward group will increase in the level of happy mood from pre-performance to performance. Although the reward group obtained higher scores than the punishment group for happiness, both groups decreased in the level of happiness from pre-performance to performance. While the decrease in happy mood for the punishment group is consistent with Gray’s theory, the decrease for the reward group was unexpected, and is not consistent with Gray’s theory. One reason for this finding may be that the pressures associated with performance of the go/no-go task may have masked positive affects experienced by Ss. Indeed the finding that both groups reported higher
314
Rapson Gomez and Suzanne McLaren
levels of stress during performance provides indirect support for this view. Another explanation may be that the reward condition used in this study may not have been strong enough to produce positive moods. Unlike the study by Carver and White (1994), which provided progressive feedback during performance of earning extra experimental participation credit points (irrespective of performance), this study rewarded Ss with 10 cents for each correct response. It may be that for students, experimental participation credit points are more powerful reinforcers than small amounts of money. A third explanation may be that the BAS may not be crucial in relation to positive moods. As Ss in the Carver and White (1994) study were asked to complete their ratings of happiness after being told that they had earned the extra experimental participation credit points, it is possible that this may have accounted for the higher happiness reported by Ss. Based on Fowles’ (1980) suggestion that HR is more strongly associated with BAS activity than BIS activity, it was expected that reward (associated with activation of the BAS) would lead to increased HR. The results in this study showed no change in HR from pre-performance to performance for either group, and no difference between the groups during performance. These findings are inconsistent with Fowles’ (1980) view] that HR reflects BAS activity more than BIS activity. However, the findings in this study need to be interpreted cautiously as it is possible that (as suggested earlier) the reward used may not have been strong enough to produce changes in BAS activation to the degree required to produce noticeable differences in HR. Indeed the findings of no change in arousal level from pre-performance to performance in both groups provides indirect support for this argument. However, the possibility that increased HR may not result from BAS activation cannot be overlooked. Indeed, a recent study also reported no change in HR in a condition involving monetary reward (Sosnowski, Nurzynska & Polec, 1991). Fowles (1980) has also suggested that electrodermal activity reflects BIS activity. Consistent with this view, results demonstrated a higher SCL, and also significant increase in SCL with time given to the task in the punishment group compared with the reward group. The findings also support existing data that show a link between impulsivity and higher electrodermal activity when faced with impending punishment (Hare, 1978). Overall, the findings that punishment resulted in lower disinhibitory responses, more negative mood, and higher SCL, while reward resulted in more disinhibitory responses and positive mood support Gray’s BAS and BIS theory. However, it must be noted that these findings can also be interpreted in terms of Eysenck’s theory (Eysenck, 1967) that links differences in learning to arousal level and arousability. According to Eysenck, high arousal leads to more learning (i.e approach), while low arousal leads to less learning (i.e. avoidant). Thus, based on Eysenck’s theory, the differences noted in the two groups can be explained in terms of the low arousal produced by the punishment, and the high arousal produced by the reward. Gray’s theory also suggests that the BIS and BAS are two separate neurophysiological systems, and that the BIS is linked to trait anxiety, while the BAS is linked to trait impulsivity. Thus it was expected that the behavioural, emotional and psychophysiological responses thought to be linked to each of the systems will be associated with each other, and with the respective personality dimensions. The results in this study failed to support this, Response disinhibition, happy mood and HR were not associated with each other in the reward condition, while response inhibition, nervous mood and SCL were not associated with each other in the punishment condition. Also, response disinhibition? happy mood and FIR were not associated with trait impulsivity; and response inhibition, nervous mood and SCL were not associated with trait anxiety. Consistent with this study, Corr, Pickering, and Gray (1995) found no association between approach behaviour and impulsivity in a reward condition, and between avoidance behaviour and anxiety in a punishment condition. Taken together, these findings raise the possibility that the neurophysiological processes of the various responses, believed to be associated within each of Gray’s behavioural systems, may be somewhat different, and that the BJS and BAS may not be linked to trait anxiety and impulsivity, respectively. These findings are inconsistent with Gray’s personality theory. The findings here are consistent with the notion that disorders with major deficits in response inhibition, such as psychopathy, delinquency, and conduct disorder are related to an overactive BAS (Quay, 1988, 1993), and that impulsivity is unlikely to be related to an underactive BIS (e.g. Gray ef al., 1983; Newman, 1987). Furthermore, as nervousness is a core symptom of anxiety, it can be argued that the increase in nervous mood from pre-perfo~ance to performance, as well as
Gray’s BAS/BIS theory
315
the higher level of nervousness in the punishment group (but not the reward group), is consistent with the view linking BIS activation to high anxiety (Geen, 1985a, 1985b, 1987; Hagopian & Ollendick, 1994). In summary, the findings in this study are consistent with Gray’s BAS and BIS theory. However there was no support for Gray’s view linking the BIS to trait anxiety, and the BAS to trait impulsivity. Corr et al. (1995) have pointed out that it cannot be assumed that the relations between personality, reinforcement, moods, behaviour and psychophysiological responses in associative and instrumental learning will be the same. Indeed their study indicates some differences. It is to be noted that although the performance of the go/no-go task required instrumental learning, the task also involved associative learning, as Ss had to learn which numbers (conditioned stimuli) predicted the reward or punishment (unconditional stimuli). Thus it is possible that the associative learning involved in performance of the go/no-go task may have influenced the findings in this study. In view of the findings of Corr et al. (1995), there is need for some caution in the conclusions drawn. Clearly more studies aimed at ‘directly’ testing Gray’s theory, as in this study, are needed. In this respect, studies using ‘pure’ associative and instrumental learning tasks, such as those used by Corr et al. (1995), will be useful. Acknowledgements-We
are grateful to Dr John Winkelman, School of Behavioural and Social Sciences and Humanities, University of Ballarat, for writing the computer program for the go/no-go task. The study was supported by a grant from the School of Behavioural and Social Sciences and Humanities, University of Ballarat.
REFERENCES Carver, C. S. & White, T. L. (1994). Behavioral inhibition, behavioral activation, and affective responses to impending reward and punishment: The BIS/BAS scales. Journal ofPersonality and Social Psychology, 67, 319-333. Corr, P. J., Pickering, A. D. & Gray, J. A. (1995). Personality and reinforcement in associative and instrumental learning. Personality
Eysenck, Eysenck,
and Individual Differences,
19, 47-7
I.
H. J. (1967). The biological basis ofpersonality. Springfield, IL: Thomas. S. & Eysenck, H. (1977). The place of impulsiveness in a dimensional system of personality
Journal
of Psychology,
description.
British
16, 57-68.
Fowles, D. C. (1980). The three arousal model: Implications of Gray’s two-factor learning theory for heart rate, electrodermal activity, and psychopathy. Psychophysiology, 17. 87-104. Geen, R. G. (1985). Evaluation apprehension and response withholding in solution of anagrams. Personality and Individual Differences,
6, 293-298.
Geen, R. G. (1985). Test anxiety and visual vigilance. Journal qf Personalityand Social Psychology, 49, 363-370. Geen, R. G. (1987). Anxiety and behavioral avoidance. Journal of Research in Personality, 21,481488. Gorenstein, E. E. & Newman, J. P. (1980). Disinhibitory psychopathology: A new perspective and a model for research. Psychologicul Review, 87, 301-315. Gray, J. A. (1970). The psychophysiological basis of introversion%xtraversion. Behavior Research and Therapy, 8,249-266. Gray, J. A. (1981). A critique of Eysenck’s theory of personality. In H. J. Eysenck (Ed.), A modelfor personality (pp. 246 276). New York: Springer. Gray, J. A. (1982). The neuropsychology of anxiety. New York: Oxford University Press. Gray, J. A. (1987). The psychology offear and stress (2nd edn). Cambridge, England: Cambridge University Press. Gray, J. A. (1990). Brain systems that mediate both emotion and cognition. Cognition and Emotion, 4, 269-288. Gray, J. A., Owen, S., Davis, N. & Tsaltas, E. (1983). Psychological and physiological relations between anxiety and impulsivity. In M. Zuckerman (Ed.), Biological bases qfsensation seeking, impulsioity and anxiety (pp. 18 l-217). Hillsdale, NJ: Erlbaum. Hagopian, L. P. & Ollendick, T. H. (1994). Behavioral inhibition and test anxiety: An empirical investigation of Gray’s theory. Personality and Indiuiduul Difflences, 16, 597-604. Hare, R. D. (1978). Electrodermal and cardiovascular correlates of psychopathy. In R. D. Hare & D. Schalling (Eds), Psychopathic behavior: Approaches to research (pp. 107-144). New York: Wiley. Hutt, J. & Weidner, G. (1993). The effects of task demand and decision latitude on cardiovascular reactivity to stress. Behavioral
Medicine,
18, 181L188.
Kelsey, R. M. (1991). Electrodermal lability and myocardial reactivity to stress. Psychophysiology, 28, 619431. King, M. G., Burrows, G. D. & Stanley, G. V. (1983). Measurement of stress and arousal: Validation of the stress/arousal checklist. British Journal of Psychology, 74, 413479. Matthews, G., Davies, D. R. & Lees, J. L. (1990). Arousal, extraversion, and individual differences in resource availability. Journal
of Personalit),
and Social Psychology,
59, 150-l 68.
McCleary, R. A. (1966). Response modulating function of the limbic system: Initiation and suppression. In E. Stellar & J. M. Sprague (Eds), Progress in physiologicalpsychology (Vol. I, pp. 209-271). San Diego, CA: Academic Press. Newman, J. P. (1987). Reaction to punishment in extraverts and psychopaths: Implications for the impulsive behavior of disinhibited individuals. Journal of Research in Personality, 21, 464-480. Newman, J. P. & Kosson, D. S. (1986). Passive avoidance learning in psychopathic and nonpsychopathic offenders. Journal of Abnormal
Newman,
Psychology,
J. P., Patterson,
Psychology,
96, 145-148.
96, 145-148.
C. M. & Kosson,
D. S. (1987). Response
perseveration
in psychopaths.
Journal
of Abnormal
316
Rapson
Gomez and Suzanne
McLaren
Newman, J. P., Widom, C. S. & Nathan, S. (1985). Passive avoidance in syndromes of disinhibition: Psychopathy and extraversion. Journal of Personality and Social Psychology, 48, 1316-l 327. Obrist, P. A. (1976). The cardiovascular-behavioral interaction as it appears today. Psychophysiology, 1.3, 95-107. Patterson, C. M. & Newman, J. P. (1993). Reflectivity and learning from aversive events: Toward a psychological mechanism for the syndromes of disinhibition. Psychological Review, 100, 716736. Quay, H. C. (1988). The behavioral reward and inhibition system in childhood behavior disorders. In L. M. Bloomingdale (Ed.), Attention de&it disorder (Vol. 3, pp. 176186). Oxford: Pergamon Press. Quay, H. C. (1993). The psychobiology of undersocialized aggressive conduct disorder: A theoretical perspective. Development and Psychopathology, 5, 1655180. Repetti, R. L. (1993). Short-term effects of occupational stressors on daily mood and health complaints. Health Psychology, 12, 125-131. Sosnowski, T., Nurzynska, M. & Polec, M. (1991). Active-passive coping and skin conductance and heart rate changes. Psychophysiology, 28, 665-672. Spielberger, C. D., Gorsuch, R., Lushene, R., Vagg. P. R. & Jacobs, G. A. (1983). Manual for the Stak~Trait AnxiefJ Inventory (Form r). Palo Alto, CA: Consulting Psychologists Press.