and premeditated- aggression

330 Pages·2011·1.26 MB·English

The Role of the Prefrontal Cortex in the Expression of Impulsive- and
Premeditated-Aggression

by

Sarah Haberle BA (Hons)

Submitted in fulfilment of the requirements for the Degree of Doctor of Philosophy
(Clinical Psychology)

School of Psychology
University of Tasmania
October 2011
This thesis contains no material, which has been accepted for a degree or
diploma by the University or any other institution, except by way of background
information and duly acknowledged in the thesis. To the best of my knowledge and
belief, this thesis contains no material previously published or written by another
person except where due acknowledgement is made in the text of the thesis, nor does
the thesis contain any material that infringes copyright.

__________________________________ Date: _______________
Sarah Haberle

The research associated with this thesis abides by the international and
Australian codes on human and animal experimentation, the guidelines by the
Australian Government’s office of the Gene Technology Regulator and the rulings of
the Safety, Ethics and Institutional Biosafety Committees of the University.

__________________________________ Date: _______________
Sarah Haberle

This thesis may be made available for loan and limited copying in accordance
with the Copyright Act 1968.

__________________________________ Date: _______________
Sarah Haberle
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Abstract

The notion that there is a relationship between frontal lobe damage and
aggressive behaviour has been recognised in the clinical literature for over 50 years.
However, although there is evidence for an association between general brain
dysfunction and aggression, there is little evidence pertaining to subclinical
impairment and the propensity for aggressive behaviour. Further to this, given the
functionally heterogeneity of the prefrontal cortex, it is vital to delineate the specific
roles of the dorsolateral, orbitofrontal and medial aspects of the prefrontal cortex in
the expression of aggression.
Two forms of aggression are distinguished: reactive, impulsive-aggression
and goal-directed premeditated aggression. While impulsive-aggression is typically
described as an emotionally-charged aggressive response characterised by a lack of
control, premeditated aggression is considered to be a planned and controlled
aggressive display that is instrumental in nature. The qualitative differences between
these subtypes of aggression suggest distinct neuropsychological differences
mediating the likelihood of their display.
The aim of this thesis was to clarify the role of the prefrontal cortex in
subclinical impulsive-aggression and premeditated aggression. More specifically,
possible executive functioning deficits mediated by the dorsolateral prefrontal cortex,
and emotion recognition, impulsivity, and response reversal capabilities mediated by
the orbitofrontal cortex were explored. Participants included university
undergraduate students identified as having high levels of trait aggression, classified
as either predominantly impulsive, or predominantly premeditated in nature.
Experiment 1 (n=85) explored possible executive deficits using a battery of
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neuropsychological measures pertaining to dorsolateral functioning. It was found that
impulsive-aggressive individuals performed significantly poorer on measures of
cognitive flexibility, planning, problem-solving, and flexibility of verbal thought
processes.
Experiment 2 (n=87) sought to identify possible deficits in interpretations of
facial expressions of emotion and hostile attribution biases. Contrary to expectations,
the results indicated that while impulsive- and premeditated-aggressive individuals
do not incorrectly interpret emotional expressions, premeditated-aggressive
individuals attributed greater levels of aggression to neutral faces.
Experiment 3 (n=87) investigated functions of the orbitofrontal cortex,
namely impulsivity, response reversal, and decision-making capabilities. No
differences between impulsive-aggressive and premeditated-aggressive individuals
were found on any of these measures suggesting negligible involvement of the
orbitofrontal cortex in subclinical aggression.
Overall, the results from this thesis suggest distinct neuropsychological
processes in individuals who display predominantly impulsive-aggressive behaviour
compared to those who display predominantly premeditated-aggression. While
impulsive-aggression may result from executive dysfunction pertaining to the
dorsolateral region of the prefrontal cortex, the display of premeditated aggression is
related to functioning of the orbitofrontal cortex mediating the interpretation of
aggression in others. Such findings have important implications not only in the
understanding of the causal features of such behaviour, but also in the development
and implementation of successful treatment strategies.

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Acknowledgements

I would like to express my thanks to friends and colleagues whose support and
encouragement have made this thesis possible. Most importantly, I would like to
thank my supervisor Dr Frances Martin for her continued help and support throughout
my candidature. I greatly appreciate your patience and flexibility, your honesty, and
your continued encouragement. I would also like to thank Dr Raimondo Bruno, Dr
Clive Skilbeck, and Dr Tess Crawley for their valued feedback on my research and
other academic and support staff within the School of Psychology at the University of
Tasmania, particularly Vlasti Broucek and David Chadderton for IT and technical
support, and Sue Ross and Susan Jopling for answering all my questions and helping
out in every way they possibly could. Thank you to all members of the annexe,
especially my roomies Megan Laugher and Matt Treeby for the many laughs, songs,
murals, mega-cards, and dances over the years. Lastly, I would like thank all of my
friends and family for their patience, advice, and understanding, and being so
supportive and encouraging especially when I needed it most.
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Table of Contents

Abstract

Acknowledgements

List of Tables

List of Figures

Chapter 1. Overview of the Thesis p. 1

Chapter 2. Impulsive- and Premeditated-Aggression: A Review of
the Literature p. 6

2.1 Aggression p. 6
2.2 Distinguishing between impulsive- and premeditated-
aggression p. 7
2.2.1 Psychobiological evidence p. 11
2.2.2 Psychophysiological evidence p. 12
2.2.3 Neuropsychological evidence p. 14
2.2.4 Psychopathy p. 15
2.3 Importance of distinguishing between impulsive- and
premeditated-aggression p. 17

Chapter 3. Prefrontal Cortex & Aggression p. 20

3.1 The prefrontal cortex p. 22
3.2 Prefrontal divisions p. 24
3.3 Prefrontal dysfunction and aggression p. 28
3.3.1 Lesion studies p. 28
3.3.2 Neuroimaging and clinical neurological findings p. 32
3.4 The specific roles of the orbitofrontal and dorsolateral
prefrontal cortex in aggression p. 35
3.5 The role of the prefrontal cortex in impulsive- and
premeditated-aggression p. 37
3.6 Subcortical structures p. 40
3.7 Conclusion p. 41

Chapter 4. Rationale p. 42

Chapter 5. Study 1: Executive Functioning p. 46

5.1 Neuroanatomy of executive functions p. 47
5.2 Executive functioning measures p. 50
5.2.1 Verbal Fluency Test p. 50
5.2.2 Trail Making Test p. 51
5.2.3 Tower of Hanoi p. 52
5.2.4 Stroop Colour-Word Interference Task p. 53
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5.2.5 The Brixton Test p. 54
5.3 Executive functioning and aggression – a review of previous
research p. 55
5.4 Executive functioning and impulsive- and premeditated-
Aggression p. 57
5.5 The relationship between executive functioning deficits and
aggression p. 60
5.6 Limitations of other studies p. 62
5.7 Aim and hypotheses p. 64
5.8 Method p. 65
5.8.1 Participants p. 65
5.8.2 Materials p. 70
5.8.2.1 Questionnaires p. 70
5.8.2.2 Executive function measures p. 73
5.8.2.3 Wechsler Adult Intelligence Scale –
Third Edition p. 77
5.8.3 Procedure p. 78
5.9 Results p. 80
5.9.1 Participants p. 80
5.9.2 Executive function measures p. 82
5.9.3 Wechsler Adult Intelligence Scale – Third Edition p. 83
5.10 Discussion p. 85
5.10.1 Verbal Fluency Test p. 87
5.10.2 Trail Making Test p. 88
5.10.3 Tower of Hanoi p. 90
5.10.4 Stroop Colour-Word Interference Task p. 92
5.10.5 The Brixton Test p. 95
5.10.6 Personality measures p. 96
5.10.7 Psychopathy and Antisocial Personality Disorder p. 98
5.10.8 The link between executive functioning deficits and
impulsive-aggression p. 100
5.10.9 Conclusion p. 103

Chapter 6. Study 2: Emotion Recognition and Aggression Attribution p. 107

6.1 Neural systems involved in emotion recognition p. 109
6.2 Separable neural systems for different emotional expressions p. 113
6.3 The relationship between emotion recognition and aggression p. 115
6.4 Aim and hypotheses p. 124
6.5 Method p. 125
6.5.1 Participants p. 125
6.5.2 Materials p. 127
6.5.2.1 Questionnaires p. 127
6.5.2.2 Facial recognition tasks p. 128
6.5.2.3 Wechsler Adult Intelligence Scale –
Third Edition p. 129
6.5.3 Procedure p. 129
6.6 Results p. 131
6.6.1 Participants p. 131
6.6.2 Emotion recognition task p. 132
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6.6.3 Aggression rating task p. 142
6.6.4 Wechsler Adult Intelligence Scale – Third Edition p. 150
6.7 Discussion p. 150
6.7.1 Emotion recognition task p. 150
6.7.2 Aggression rating task p. 155
6.7.3 Personality measures p. 157
6.7.4 The link between emotion recognition and aggression p. 157
6.7.5 Conclusion p. 159

Chapter 7. Study 3: Inhibition, Response Reversal, and
Decision-Making p. 161

7.1 Inhibition p. 161
7.1.1 Inhibition and the frontal lobes p. 164
7.1.2 Inhibition measures p. 166
7.1.3 Inhibition and aggression p. 169
7.2 Response reversal p. 171
7.2.1 Response reversal and the frontal lobes p. 172
7.2.2 Response reversal measures p. 174
7.2.3 Response reversal and aggression p. 177
7.3 Decision-making p. 180
7.3.1 Decision-making and the frontal lobes p. 181
7.3.2 Decision-making measures p. 181
7.3.3 Decision-making and aggression p. 184
7.3.4 Somatic marker hypothesis p. 186
7.4 Impulsivity, response reversal, decision-making, and aggression p. 187
7.5 Aim and hypotheses p. 188
7.6 Method p. 189
7.6.1 Participants p. 189
7.6.2 Materials p. 189
7.6.2.1 Questionnaires p. 189
7.6.2.2 Inhibition, response reversal, and
decision-making tasks p. 189
7.6.2.3 Wechsler Adult Intelligence Scale –
Third Edition p. 191
7.6.3 Procedure p. 191
7.7 Results p. 195
7.7.1 Stop Signal Task p. 195
7.7.2 Intra/Extra Dimensional Set Shift task p. 196
7.7.3 Cambridge Gambling Task p. 198
7.8 Discussion p. 202
7.8.1 Stop Signal Task p. 203
7.8.2 Intra/Extra Dimensional Set Shift task p. 207
7.8.3 Cambridge Gambling Task p. 210
7.8.4 Limitations and directions for future research p. 212
7.8.5 Conclusion p. 213

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Chapter 8. General Discussion p. 215

8.1 Overview of findings p. 215
8.1.1 Executive functioning p. 215
8.1.2 Emotion recognition and aggression attribution p. 218
8.1.3 Inhibition, response reversal, and decision-making p. 219
8.2 Theoretical implications p. 220
8.2.1 Inhibition p. 222
8.2.2 Premeditated-aggression p. 224
8.3 Clinical implications p. 226
8.4 Limitations p. 228
8.5 Conclusion p. 229

References p. 231

Appendices p. 307

Appendix A: HREC approval letter p. 308
Appendix B: Information sheet for Study 1 p. 310
Appendix C: Consent form for Study 1 p. 312
Appendix D: Facial stimuli from Ekman and Friesen’s (1976)
collection used for the emotion recognition task p. 313
Appendix E: Facial stimuli from Ekman and Friesen’s (1976)
collection used for the aggression rating task p. 314
Appendix F: Information sheet for Study 2 and Study 3 p. 315
Appendix G: Consent form for Study 2 and Study 3 p. 317
Appendix H: Data analyses CD
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List of Tables

Chapter 5
Study 1: Executive Functioning
Table 5.1 The Impulsive-Premeditated Aggression Scale p. 67
Table 5.2 Number of males and females in the three participant
groups and total sample p. 68
Table 5.3 Mean (and standard deviation) scores on the Aggression
Questionnaire – Short Form and ages for the three
participant groups and total sample p. 69
Table 5.4 Means (and standard deviations) for the Aggression
Questionnaire – Full Scale and I7 Impulsivity
Questionnaire for the three participant groups p. 81
Table 5.5 Means (and standard deviations) for the three participant
groups on the executive function and WAIS-III measures p. 84
Table 5.6 Results of ANOVAs for the executive function and
WAIS-III measures p. 85

Chapter 6
Study 2: Emotion Recognition and Aggression Attribution
Table 6.1 Number of males and females in the three participant
groups and total sample p. 126
Table 6.2 Mean (and standard deviations) scores on the Aggression
Questionnaire – Short Form and ages for the three
participant groups and total sample p. 127
Table 6.3 Means (and standard deviations) for the subscales of the
Aggression Questionnaire – Full Scale and I7 Impulsivity
Questionnaire for the three participant groups p. 132
Table 6.4 Mean (and standard deviations) number of correct
responses (maximum = 4) on the emotion recognition task
for the three participant groups p. 133
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