Supplemental Materials

Reduced Transfer of Affective Value to Instrumental Behavior in Violent Offenders

by V. Ly et al., 2016, Journal of Abnormal Psychology

http://dx.doi.org/10.1037/abn0000166

Appendix S1 – Demographic data

Questionnaires and interviews

Participants were screened by trained interviewers for Axis-I and Axis-II psychiatric disorders

using the Dutch version of the Mini International Neuropsychiatric Interview (MINI; Van Vliet,

Leroy, & Van Megen, 2000) and the Structured Clinical Interview for DSM-IV disorders (SCID-II;

Weertman, Arntz, & Kerkhofs, 2000) respectively. The National Adult Reading Test was used to

assess IQ (NART; Schmand, Bakker, Saan, & Louman, 1991). Subjective trait anxiety was

measured using the self-report State-Trait Anxiety Inventory (STAI; Van der Ploeg, Defares, &

Spielberger, 1980). Additional scores on aggressive traits and psychopathic tendencies were

assessed using the Impulsive Premeditated Aggression Scale (IPAS; Kuyck, De Beurs,

Barendregt, & Van den Brink, 2013) and the Psychopathy Checklist-Revised (PCL-R; Hare, Hart,

& Harpur, 1991; Hildebrand, De Ruiter, & Nijman, 2004).

Mini International Neuropsychiatric Interview. The MINI is a brief structured diagnostic

interview, developed to assess psychiatric diagnoses according to DSM-IV axis-I and ICD-10

criteria. The interview consist of 26 modules, with each of the modules corresponding to a

diagnostic category. Each module starts with one or two screening questions. During the

interview, a professional trained for psychiatric diagnostic interviews determines whether a

responder scores on each of the symptoms to meet criteria. Good psychometric characteristics

of the MINI have been demonstrated previously (Sheehan et al., 1998).

Structured Clinical Interview for DSM-IV axis-II disorders. The SCID-II is a semi-structured

interview, which is used to assess personality disorders. The interview consists of 134 questions

grouped per disorder. Several studies have shown good reliability of the SCID-II (Ball,

Rounsaville, Tennen, & Kranzler, 2001; Ekselius, Lindstrom, von Knorring, Bodlund, & Kullgren,

1994).

National Adult Reading Test. The Dutch version of the NART consists of a series of words with

an irregular pronunciation. This reading test is in particular suitable for research purposes and

has been proposed as a simple measure for obtaining an estimation of premorbid IQ. Good

inter- and intra-rater reliability has been shown previously for this test (Lugt, Ponds, Rozendaal,

Houx, & Jolles, 1995).

State-Trait Anxiety Inventory. Trait anxiety was assessed using the Dutch version of the STAI

(Van der Ploeg, Defares, & Spielberger, 1980), which is a 20-item self-report questionnaire on

which participants rate how anxious they feel in general, using a scale ranging from 1 (not at all)

to 4 (very much so). The Dutch version of the STAI has been shown to have good validity and

reliability (Van der Ploeg, 1981).

Impulsive Premeditated Aggression Scale. For the current study, we have used the Dutch

version of the IPAS (Kuyck et al., 2013). The IPAS is a 30-item self-report questionnaire that

measures impulsive and premeditated aggression in the last six months. Participants indicated

how much each item characterized their latest act of aggression, ranging from 1 (strongly

disagree) to 5 (strongly agree). This Dutch version of the IPAS has been shown to have good

psychometric properties, although the two subscales reflecting impulsive and premeditated

aggression were shown to be highly correlated (Kuyck et al., 2013).

Psychopathy Checklist-Revised. The PCL-R is a structured interview, which can be used to assess

the presence of psychopathy in individuals (Hildebrand et al., 2004). The PCL-R consists of 20

items that target personality characteristics and behavioral patterns. These items are rated on a

scale from 0 to 2, with 0 = absent, 1 = may be present, and 2 = definitely present. Factor

analysis of the PCL-R indicated that it consists of two factors: factor 1 relates to interpersonal

and affective deficits; factor 2 relates to lifestyle and anti-social behaviors. PCL-R scores were

obtained by two clinicians based the structured PCL-R interview, clinical status and prior

history. These clinicians were certified to administer and score the PCL-R after an intensive

three-day training that comprises theoretical and practical aspects using case-material and

clinical videos. Although the clinician raters were staff personnel from the forensic institutions,

which could undermine the reliability of the ratings (e.g., Edens, Boccaccini, & Johnson, 2010),

the clinicians were not involved in the treatment of the participants. Moreover, two raters

always compared their scores after independent scoring and came to a consensus score. When

no consensus could be found, a third independent rater was included in the process. Using

similar procedures, good to excellent inter-rater reliability has previously been demonstrated in

a Dutch sample of male violent offenders (Total score: 0.88; Factor 1: 0.76, Factor 2: 0.83;

Hildebrand et al., 2004), and also in Dutch sexual offenders (Total score: 0.84, Factor 1: 0.71,

factor 2: 0.77; Schönberger, Hildebrand, Spreen, & Bloem, 2008).

Demographic data

Demographic data are presented in Table 1. The groups differed significantly in age (F(1,55) = 6.8,

p = 0.012, ηp2 = 0.110, 95% CI [0.005; 0.272]) and IQ (F(1,55) = 7.2, p = 0.010, ηp

2 = 0.116, 95% CI

[0.007; 0.279]). Furthermore, the violent offenders scored higher on trait anxiety (F(1,55) = 6.2, p

= 0.015, ηp2 = 0.101, 95% CI [0.003; 0.262]) and premeditated aggression (F(1,55) = 7.2, p = 0.010,

ηp2 = 0.116, 95% CI [0.007; 0.279]), but not on impulsive aggression (F(1,55) = 0.01, p = 0.918, ηp

2 <

0.01, 95% CI [0.000; 0.008]) compared with the controls. Violent offenders showed an average

total score of 22.4 (SD= 8.6) on the PCL-R (Hare et al., 1991; Hildebrand et al., 2004). There

were 14 out of 37 who scored at or above the European cutoff of 26 as an indication for

psychopathy; and 6 out of 37 who scored at or above the North American cutoff of 30 as an

indication for psychopathy (Hildebrand et al., 2004).

To examine the validity of the self-report of aggression and the PCL-R scores, we correlated the

subscales of the IPAS with the PCL-R score as a whole and with each of the two separate factors

of the PCL-R. Based on literature with regard to PCL-R psychopathy and aggression, we would

expect that the two PCL-R factors show differential relations with the two aggression subscales

(i.e., Factor 1 more related to premeditated, Factor 2 more related to impulsive aggression).

However, these analyses only revealed a marginal correlation between PCL-R Factor 2 with

impulsive aggression (r = 0.299, p = 0.073). This was not observed for the correlational analysis

for PCL-R factor 2 and self-reported premeditated aggression score (r = -0.105, p = 0.535). A test

of difference between two dependent correlations resulted in a marginal effect (Z-score =1.72,

p = .085). No other significant relations were observed between the PCL-R and the IPAS (all r <

0.017, p > 0.921). This lack of an association suggests that we should be careful with the

interpretation of the scores for aggression and psychopathic tendencies in this group of violent

offenders.

Table 1. Demographic dataViolent offenders Controls F, p-value

Age 37.7 (9.6) 44.7 (10.7) 6.8, 0.012*

National adult reading test 93.9 (9.7) 100.9 (8.2) 7.2, 0.010*

Axis-II personality disorders

Narcissistic 9a

Borderline 5a

Anti-social 33a

Trait anxiety 37.1(10.2) 30.6(6.2) 6.2, 0.015*

Impulsive premeditated aggression scaleb

Premeditative 2.5 (.75) 1.9 (.69) 7.2, 0.010*

Impulsive 2.3 (.82) 2.3 (.77) 0.01, 0.918

Psychopathy checklist revised total

22.4 (7.5) [2-34] - -

Factor 1 9.1 (3.4) [2-34]

Factor 2 10.6 (4.0) [2-34]

Mean (SD) [range]; *p<0.05

aNumber of individuals

b1= low in aggression; 5= high in aggression.

Appendix 2 – Experimental paradigm

Experimental set-up

The balance board consists of a custom-made strain gauge force plate (dimensions: 1 m x 1 m;

sampling frequency: 100 Hz) with four sensors measuring forces in the (vertical) z-direction.

Time series of the center of pressure, for the anterior-posterior (AP) and the medio-lateral (ML)

direction were derived from the signals of these sensors. Visual stimuli of the task were

presented 1 m in front of the participant at eye level on a 22-inch height-adjustable screen.

Affective decision making task

Participants had to learn optimal responses – by trial and error – to instrumental targets based

on monetary feedback (wins/losses of €0.20). Instrumental responses consisted of whole body

go- and nogo-responses upon these instrumental targets. To induce affective influences on the

instrumental response, a task-irrelevant (angry/happy) face stimulus was presented on each

trial prior to the presentation of an instrumental target.

The task consisted of two blocks (120 trials each) with different action-contexts: approach and

avoidance, and the order randomized across participants. This manipulation of action-context

determined whether a go-response upon an instrumental target was an approach- or an

avoidance-action. Thus, participants could make four types of instrumental responses across

the whole task: approach-go, approach-nogo, avoidance-go, avoidance-nogo. Participants had

to learn within each block whether a go- or nogo-response was optimal (i.e., with higher

probability of a win) for each of the 6 different instrumental targets (12 across the whole task).

Within each block, the optimal response was a go-response for half of the instrumental targets;

whereas a nogo-response was optimal for the other half. This resulted in a multi-factorial

design, with affective prime (angry/happy), action-context (approach/avoidance), and optimal

response (go/nogo) manipulated independently (Table 2). The responses were probabilistically

reinforced: the optimal response would lead to a win in 80 percent (a loss in 20 percent) of the

time. Participants were only informed that correct choices were reinforced probabilistically, but

not about the exact nature of the probabilistic associations. Participants were informed about

the monetary gain as a bonus (€10 maximum on top of the reimbursement) to enhance

ecological validity and motivation during this task.

Participants were required to make whole body go- and nogo-responses on the balance board.

For a nogo-response (approach-nogo/avoid-nogo), participants remained stationary at the

center of the board. For a go-response (approach-go/avoidance-go), participants made sideway

(not forward/backward) steps towards (approach-go) or away from (avoid-go) the side where

the target was presented to approach or avoid the target respectively. The side on which the

target was presented (left or right) was counterbalanced for each target.

Trial events. First, the affective face-prime (angry/happy) was presented centrally on the screen

(3000ms). Participants were instructed to maintain their view on these stimuli, while remaining

stationary. After face-prime offset, the instrumental target appeared either on the left or the

right side of the screen, upon which the participant had to make a go- or nogo-response. The

response window was fixed at 2500 ms. Response feedback in terms of a square turning orange

for a go-response; remaining white for a nogo-response was provided (500ms) before the

monetary outcome (1000ms). Intertrial interval was jittered (3000 ± 1000ms). If a go-response

had been made, participants were required to return to their starting position (i.e., the center

of the board) at the outcome presentation.

Visual stimuli. Face-primes consisted of adult Caucasian faces from 36 models (18 male) from

several databases (Ekman & Friesen, 1976; Matsumoto & Ekman, 1988; Martinez & Benavente,

1988; Lundqvist et al., 1998). Model identity was counterbalanced for each instrumental target.

Each model showed two expressions (angry/happy), matched for brightness and contrast. Faces

were trimmed to exclude influence from hair and nonfacial contours (van Peer et al., 2007). The

instrumental targets consisted of 12 different colored shapes. The affective primes and the

instrumental targets were randomly assigned to the two blocks, such that different affective

and instrumental stimuli occurred in the two blocks. Stimulus presentation and response

acquisition were controlled by Presentation 14.8 12.30.10 (Neurobehavioral Systems Inc.,

Berkeley, CA).

Table 2. Task-design. Affective prime (angry/happy), action-context (approach/avoidance), and

optimal response (go/nogo) were manipulated independently.

Action-context Affective prime

Optimal response

Probablistic reinforcement: +/- € 0.20

Approach (120)

Instrumental targets:1-3 Angry (30) Go (60) p(reward|go)=0.8,p(punish|go)=0.2 Happy (30)

Instrumental targets:4-6 Angry (30)Happy (30)

Nogo (60) p(reward|go)= 0.2,p(punish|go)=0.8

Avoidance (120)

Instrumental targets:7-9 Angry (30)Happy (30)

Go (60) p(reward|go)= 0.8,p(punish|go)=0.2

Instrumental targets:10-12

Angry (30)Happy (30)

Nogo (60) p(reward|go)= 0.2,p(punish|go)=0.8

(N)=N trials

Appendix S3 - Affective biasing of instrumental action with age- and IQ-matched groups

To explore and rule out any potential influence of age and IQ on the group effect on affective

biasing of instrumental action, an additional analysis was conducted with 19 violent offenders

who best matched the control group average (n=19) in terms of age and IQ based on nearness

in a two-dimensional Euclidean space using the Distance Formula and standardized values of

age and IQ (Spiel et al., 2008). After this procedure, there were no differences between the

matched groups in terms of age and IQ (F(1,37) = 2.1, p = 0.103, ηp2 = 0.054, 95% CI [0.000; 0.231];

and F(1,37) = 2.8, p = 0.153, ηp2 = 0.070, 95% CI [0.000; 0.256] respectively).

Consistent with our primary analysis, an ANOVA of proportion of go (Pgo) across the age- and IQ-

matched groups also yielded a significant group x emotion x action-context interaction effect

(F(1,36) = 6.00, p = 0.019, ηp2 = 0.143, 95% CI [0.003; 0.345]), indicating an affective bias in the

controls (F(1,18) = 7.94, p = 0.011, ηp2 = 0.306, 95% CI [0.018; 0.550]), but not in the violent

offenders (F(1,18) = 0.17, p = 0.684, ηp2 <0.01, 95% CI [0.000; 0.212]). These effects were not

reflected by reaction time (group x emotion x action-context; F(1,36) = 0.810, p = 0.374, ηp2 =

0.022, 95% CI [0.000; 0.178]).

In conclusion, the analysis using age- and IQ-matched groups yielded the same results as the

analyses across the whole sample. Thus, it is unlikely that the group effect on affective biasing

of instrumental action is driven by group differences in age and IQ.

Appendix S4 - Control tasks assessing affective responding

To assess whether any reduced transfer of affective value to behavior might reflect a reduction

in affective processing per se (e.g., poor affective evaluation), we also administered passive

viewing tasks and a picture rating task to the participants after the primary experiment

involving the emotional decision making task. These control tasks were designed to measure

affective processing in terms of bodily freezing (Hagenaars, Stins, & Roelofs, 2012; Roelofs,

Hagenaars, & Stins, 2010) and subjective evaluation respectively.

Control tasks

Passive viewing task. Participants were asked to remain stationary on the board while

maintaining their focus on the screen to watch a stimuli-sequence on the screen (Hagenaars et

al., 2012; Roelofs et al., 2010). There were three blocks with 20 stimuli of one type of valence

(negative, positive and neutral) presented consecutively (3s) without interval. The order of

blocks and stimuli was randomized across participants. Blocks were separated by a 5-s black

screen followed by a 2-s white fixation cross.

Visual stimuli. The face-stimuli were followed by stimuli from the International Affective Picture

System (IAPS) (CSEA, 1999). The face-stimuli consisted of adult Caucasian faces from 20 models

(10 male). Each model showed three types of expressions (angry/happy/neutral), matched for

brightness and contrast, displayed against a black background. Additionally, three sets (negative

[mutilated bodies and corpses], positive [sports] and neutral [objects]) of 20 stimuli were used

from the IAPS following previous studies (Azevedo et al., 2005; Hagenaars et al., 2012).

Picture rating task. On a 9-point Likert scale, participants scored the valence of each face-

stimulus (very happy to very angry) and IAPS pictures (very positive to very negative); and their

stress level for each of the IAPS pictures (not stressed at all to very stressed).

Data- and statistical analyses

Following Ly et al. (2014), we calculated postural mobility, which is the sway path length or sum

of the center of pressure displacements in AP and ML directions [mm/s].

Passive viewing task. To assess whether violent offenders versus controls show abnormal bodily

freezing, we performed ANOVAs with postural mobility as a dependent variable, valence

(negative/positive/neutral) as a within-subject variable and group (violent offenders/controls)

as a between-subject variable.

Picture rating task. ANOVAs were performed of the ratings, with valence

(negative/positive/neutral) as a within-subject variable and group (violent offenders/controls)

as a between-subject variable to assess whether the groups differed in terms of the subjective

evaluation of the face-stimuli and the IAPS stimuli.

Note that data from the control tasks were incomplete for three participants: we encountered

technical problems during recordings for one healthy control and one violent offender; one

violent offender refused to continue with the passive viewing task involving IAPS stimuli (see

Table 3 and 4). Analyses were only performed on data from completed tasks.

Results

All mean values of postural mobility and subjective ratings are shown in Table 3 and 4

respectively.

Passive viewing task. There were no group differences in responding to the affective stimuli in

terms of bodily freezing. This was the case for face-stimuli (F(2,52) = 1.186, p = 0.313, ηp2 = 0.044,

95% CI [0.000; 0.165]) as well as for the IAPS pictures in the passive viewing task (F(2,51) = 0.190,

p = 0.828, ηp2 < 0.01, 95% CI [0.000; 0.073]). The main effect of emotion was significant for IAPS

pictures (F(2,51) = 10.35, p < 0.001, ηp2 = 0.289, 95% CI [0.083; 0.446]), indicating reduced postural

mobility during the negative versus both the positive (F(1,52) = 12.02, p < 0.001, ηp2 = 0.188, 95%

CI [0.034; 0.361]) and the neutral IAPS stimuli (F(1,52) = 14.16, p < 0.001, ηp2 = 0.214, 95% CI

[0.049; 0.387]). No main effect of emotion was found for face-stimuli (F(2,52) = 0.506, p = 0.606,

ηp2 = 0.019, 95% CI [0.000; 0.113]). Moreover, there were no main effects of group (all F < 2.0).

Picture rating task. There were main effects of emotion for face-stimuli (F(2, 52) = 171.91, p <

0.001, ηp2 = 0.869, 95% CI [0.791; 0.902]) and IAPS pictures (valence: F(2,52) = 94.52, p < 0.001, ηp

2

= 0.784, 95% CI [0.663; 0.840]; stress: F(2,52) = 88.079, p < 0.001, ηp2 = 0.772, 95% CI [0.645;

0.831]). Ratings for each valence differed significantly from the other two (faces:

angry>neutral>happy; all F > 291.01, p < 0.001; IAPS: negative>neutral>positive; all F > 191.87,

p < 0.001). Furthermore, stress level ratings were significantly higher for the negative versus

both the positive and the neutral IAPS pictures (F(1, 53) = 155.69, p < 0.001, ηp2 = 0.746, 95% CI

[0.615; 0.814] and F(1,53) = 166.77, p < 0.001, ηp2 = 0.759, 95% CI [0.634; 0.824] respectively). The

stress level ratings for positive versus neutral IAPS pictures was not significant (F(1,53) = 0.335, p =

0.565, ηp2 < 0.01, 95% CI [0.000; 0.104]). Again, the groups did not differ in subjective

evaluation of the affective stimuli as indicated by absence of main and interaction effects for

group (all F < 1.66).

In sum, the results show that violent offenders and the healthy controls did not differ in terms

of affective processing per se. This finding needs to be replicated in future studies that also

include physiological measurements and a variety of affective stimulus sets (e.g., pleasurable-

arousing stimuli), given the possibility that the aversive mutilation scenes might not be

optimally matched to the pleasurable IAPS scenes (e.g. sports scenes) in terms of attentional

engagement.

Table 3. Mean values of postural mobility on the passive viewing taskViolent offenders Controls

Facesa

Angry 10.5 (0.7) 11.0 (0.9)

Neutral 10.5 (0.7) 10.6 (0.7)

Happy 11.0 (0.9) 10.8 (0.8)

IAPSb

Negative 13.3 (1.6) 10.3 (0.7)

Neutral 16.0 (2.6) 13.6 (1.2)

Positive 16.0 (2.2) 14.4 (1.9)

Mean values of postural mobility for emotional stimuli on the passive viewing task (mm/s) for

each group separately (SEM). aViolent offenders: n = 36; Controls: n = 19. bViolent offenders:

n=35; n = 19.

Table 4. Mean subjective evaluation ratings for stimuliViolent offenders Controls

Faces

Angry 7.7 (0.2) 7.5 (0.3)

Neutral 4.9 (0.2) 5.1 (0.1)

Happy 2.5 (0.4) 2.7 (0.4)

IAPS

Negative 8.1 (0.4); 7.0 (0.5) 8.3 (0.2); 7.6 (0.4)

Neutral 4.2 (0.4); 2.7 (0.4) 4.4 (0.3); 2.8 (0.4)

Positive 3.2 (0.4); 2.7 (0.4) 2.7 (0.3); 2.7 (0.4)

For each group separately, mean subjective valence ratings (SEM) are presented on a scale

from 1 = very happy to 9 = very angry for the face-stimuli. For the IAPS stimuli, both mean

ratings for valence (1 = very positive to 9 = very negative) and stress level (1 = not stressed at all

to 9 = very stressed) are presented [valence (SEM); stress level (SEM)]. aViolent offenders: n =

37; Controls: n = 18. bViolent offenders: n=37; n = 18.

Appendix S5 - Relation between affective biasing score and trait measures based on self-

report

In order to explore the relation between the assessed affective biasing of instrumental action

and characteristics that are specific to the violent offender sample, we performed an ANOVA

for the violent offender and control group separately with emotion and action-context as

within-subjects factors and premeditative aggression score (based on the IPAS) and trait anxiety

(based on the STAI) and their interaction as covariates.

An ANOVA within the violent offender group demonstrated a significant emotion x action-

context x premeditative aggression (F(1, 33) = 11.301, p < 0.002, ηp2 = 0.255, 95% CI [0.041;

0.460]), indicating that premeditative aggression score was positively associated with affective

biasing of instrumental action. However, an emotion x action x premeditative aggression x trait

anxiety (F(1, 33) = 4.151, p < 0.05, ηp2 = 0.112, 95% CI [0.000; 0.318]) interaction with this model

suggest that this the relation between affective biasing and aggression was modulated by

anxiety. Specifically, the combination of lower scores on trait anxiety and higher scores on

premeditative aggression was associated with low affective biasing of instrumental action.

These effects were not observed in the healthy control group (Emotion x action x premeditative

aggression: F(1,15) = 0.752, p = 0.400, ηp2 = 0.048, 95% CI [0.000; 0.311]; Emotion x action x trait

anxiety: F(1,15) = 0.731, p = 0.406, ηp2 = 0.047, 95% CI [0.000; 0.309]; Emotion x action x

premeditative aggression x anxiety: F(1,15) = 0.043, p = 0.839, ηp2 < 0.01, 95% CI [0.000; 0.098]).

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