Personality and the brain; Can brain damage change personality?
PERSONALITY AND THE BRAIN. CAN BRAIN DAMAGE CHANGE PERSONALITY? 1
Personality and the Brain. Can Brain Damage Change Personality?
Ivona S. Vukotic
Herriot Watt University
PERSONALITY AND THE BRAIN. CAN BRAIN DAMAGE CHANGE PERSONALITY? 2
From early times, a relationship between our mind and our brain, has been a great
mystery and a tempting enigma waiting to be explored and understood.
Today, neuroscience studies are giving us numerous evidence of a strong relationship
between brain and personality.
Researches have shown that when a brain changes, it usually doesn't leave the personality
intact. Personality, although considered inexplicable and vague, by definition, is group of
"more or less, stable, internal traits that make one person's behaviour consistent from one time
to another, and different from the behaviour other people would manifest in comparable
situations‟ (Child, 1968, p. 83). It is emphasized by its definition that our core characteristics
and traits should remain stabile through time and context. Naturally, people do change,
mature and grow, but their basic personality remains the same.So, what happens if personality
change after a stroke, or a head injury?
Could it be that with the change in our brain, comes the change in our mind? How
important is a role of our brain in decision making, emotions and judgment?
Is it possible that we are neurologically predisposed to have a certain personality, become
schizoids or psychopaths?If so, and if our brain is to blame and in control, how much
responsibility we have for what we are and do in life?
Neuroscientists have given us some evidence that could help us answer some of these
questions and understand the importance of brain to our cognitive functions.
Brain damage and Personality disorders
PERSONALITY AND THE BRAIN. CAN BRAIN DAMAGE CHANGE PERSONALITY? 3
"Brain damage" is a term used to describe destruction or degeneration of brain cells, which
can occur due to a wide range of internal and external factors. There are three main types of
brain damage: congenital brain damage which is caused by genetics or birth trauma, and
traumatic or acquired brain injury, which occur after birth. Neurological disorders can be
categorized according to damage localization, a primary type of dysfunction, or primary type
of cause. There are many well known diseases and conditions caused by brain impairment
such as Parkinson's disease, epilepsy, Autism, , Huntington's disease and Alzheimer's disease,
but also a number of personality disorders, which will be a focus of this essay.
Along with the progress and improvement of technology in medicine, a popularity of
brain imaging usage in studying personality disorders has increased.A strong link between
personality disturbances and criminals has urged researchers to closer examine individuals
with APD using brain imaging techniques. These studies have revealed structural and
functional damage in antisocial and violent individuals. Moreover, researches dealt with the
issue of the brain scan results usage in the legal system.
There were three basic questions to answer for a start- Primarily, do antisocial, and violent
individuals have a brain abnormality? Second, where are brain damages localized,
widespread or focal? And last, should these findings be used in legal purposes?
Antisocial Personality Disorder or Psychopathy
Results of imaging studies revealed that several brain regions have been commonly
found to be damaged in antisocial, psychopathic, and aggressive individuals, whatever the
type of imaging technique was used. Main areas of disfunction include prefrontal cortex
(particularly orbito- frontal and dorsolateral prefrontal cortex), superior temporal gyrus,
PERSONALITY AND THE BRAIN. CAN BRAIN DAMAGE CHANGE PERSONALITY? 4
amygdala–hippocampal complex, and anterior cingulate cortex. In frontal region, impairments
in prefrontal and anterior cingulate cortex resulted in impulsivity, irresponsibility, poor
decision-making, and difficulties in emotional processing. In temporal regions, the amygdala–
hippocampal and superior temporal damage contributed to antisocial issues such as inability
to follow social rules, deficiency in moral judgment, and failure to avoid punishment.
Researches have shown a weaker fear response in antisocial personality disorder
(antisocial PD) when presented a negative stimuli, such as photographs of gun accidents
(Levenston et al., 2000; Vanman et al. , 2003, and Lindberg et al., 2005) obtained a finding of
low frequency EEG activity under similar experimental conditions. In an interesting extension
of this theory, studies were taken to examine the activity septo-hippocampal system and
amygdala, the brain region responsible for learning fear. After repeated classical conditioning,
no increase in amygdala activity was found (Birbaumer et al., 2005).
Some researchers believe that the capacity for empathy, is crucial to the process of
socialization. This perspective suggests that some features of antisocial PD result of
emotional deficits such as lack of empathy. A study conducted by Blair et al. in 1997
confirms this; the group of individuals diagnosed with antisocial PD have shown less
physiological responsiveness to photos of others' suffering, as well as incapability of
recognizing emotion of fear in others (Marsh and Blair, 2008). Emotional deficits and reduced
capacity to learn fear are both associated with lower amygdala activity ( Blair , 2006). These
shortcomings are likely in the background of altered moral reasoning and behavior of
antisocial individuals, because the moral issues include concerns about the right and welfare
of others. One group of researchers, however, believes that the focus on immediate rewards is
underlying cause of this disorder. (Hiatt and Newman, 2006).
PERSONALITY AND THE BRAIN. CAN BRAIN DAMAGE CHANGE PERSONALITY? 5
In order to explore emotions in personalities with antisocial disorder , numerous
neuroendocrinological parameters have been used to measure emotional reactivity. O'Leary,
Loney and Eckel (2007) found a lower cortisol response to environmental stress in antisocial
PD. Also, the findings of both high level of testosterone and low cortisol response (Glenn et
al. , 2011 ) are interpreted in “The triple balance model of emotion” (Terburg, Morgan and van
Honk, 2009). Such relationship between these hormones reflects in motivational imbalance,
which makes the individual hyposensitive to a threator punishment and hypersensitive to
reward. Van Honk , Hormone-Jones , Morgan and Schutter (2010 ), associate this imbalance
with reactive and instrumental aggression, as a result of serotonin levels. Specifically, low
levels of serotonin, associated with impulsivity and aggression (Siever, 2008), altogether with
a high ratio of testosterone and cortisol, lead to reactive aggression in psychopaths. Antisocial
personality disorder individuals who are characterized by deficits in emotions, are more
inclined to instrumental violent acts, while those with some antisocial characteristics often
show impulsive aggressive reactions (Veit et al., 2010; Walsh , Swogger and Kosson, 2009).
There are some limitations in these studies. Even though these researches showed
strong evidence connecting brain damage and antisocial aggressive behavior, there is still a
question of heterogeneity between antisocial individuals. Their personal differences regarding
various antisocial characteristics may result in diverse degree of severity, or localization of
brain abnormalities. This theory could show inconsistency among these studies, making it
difficult to draw conclusions. Another issue arises from the fact that the studies conducted to
date are mainly cross-sectional, which makes the cause of relationship between brain damage
and antisocial behavior left unclear.
Neuroscience in court
PERSONALITY AND THE BRAIN. CAN BRAIN DAMAGE CHANGE PERSONALITY? 6
Is a killer-psychopath less responsible for a crime if his conduct is a result of brain
abnormality and genetic factors, or should he get a more severe punishment, for that very
reason, bearing in mind that there is no control over his behavior, which increases the risk of
repeating the same or similar offense? Having received information that the perpetrator of a
murder is diagnosed with an antisocial PD , judges have a tendency to impose stricter
penalties. If they are, however, presented with an expert opinion - that the psychopathic
behavior is a result of the biological consequences - they tend to impose a more lenient
sentence. In both cases, the average length of the sentence, for an offense of the same weight,
is greater when the perpetrator is not a psychopath. (Aspinwall et al.,2013).
A study conducted by three psychologists, John Monterosso, Edward B. Royzman and
Barry Schwartz, published in 2005 in the Ethics & Behavior journal, found that people often
find neuroscientific evidence as a relieve of responsibility, an excuse, for criminal actions.
Their research showed that behavior of individuals with mild brain damage subjects
experienced as automatic, unmotivated and believed that it had nothing to do with the "real"
character of the protagonist. In short, the behavior is caused, not intended.Cognitive
psychologists call this thought process a "naive dualism" - a belief that the behavior arises
either intentionally or as a result of natural laws by which the brain works. In other words, if a
behavior has psychological causes, then the person is responsible for it, but if it comes from
biological causes, then he has no control over his behavior and cannot be held responsible.
Assuming further development of neuroscience, it is not difficult to imagine a future
in which the complete, or almost complete, human psychology is explained in terms of
neurons, anatomy and biochemistry of the brain. Does that mean that no one will be held
accountable for their actions? In other words, neurocognitive explanation of human behavior
denies free will?Neurocognitive explanation of human behavior is in line with determinism.
Behavior is a product of the brain, whose structure and functions are defined by factors over
PERSONALITY AND THE BRAIN. CAN BRAIN DAMAGE CHANGE PERSONALITY? 7
which we have no control - genes and environmental conditions. Environmental component is
partly a matter of choice, but again, our choices are pre-determined by physical laws.Overall,
results from the research show that people are inclined to perceive a person with mental
disorder, if it has biological roots, as less responsible for their behavior. However, in
consideration of many research findings, it is concluded that the neurocognitive psychology,
does not eliminate the concept of personal responsibility.
In conclusion, criminals with brain impairment, whether they are capable to control
and understand their actions or not, pose a threat to society. If we bear in mind the statistic
which shows 80 percent of psychopaths repeating their offense after release from prison (Hart
et al., 1988), a conclusion would be to impose greater penalties with medical care, or other
correctional treatment in the most effective manner. However, each person should be
respectively treated as unique, as well as every case ought to be considered individually, thus
the sentencing can not be generalized.
Positive effects of brain damage - When a brain injury creates a genius
Brain damage has led to discovery of extraordinary talent in a small number of people
with autism, or who, prior to brain injury, were quite ordinary individuals.
According to American researcher Darold Treffert from the University of Wisconsin , who
has dedicated more than four decades of his life to research this phenomenon called savant
syndrome, that can be genetic or acquired (caused by brain injury or disease).Savant
syndrome is extremely rare, currently in the world there are no more than 50 people with it. It
is usually manifested by a phenomenal memory and calendar calculating, a unique
mathematical capability, mechanic skills, and talent in fine arts or music.An example of a
brain injury with such positive outcome is definitely a case of forty-year-old Derek Amato,
PERSONALITY AND THE BRAIN. CAN BRAIN DAMAGE CHANGE PERSONALITY? 8
whose life took a twist when he jumped headfirst into a shallow pool and suffered a
concussion. His head trauma resulted in 35 percent hearing loss in one ear, headaches and
amnesia. But the most dramatic consequence appeared just four days after his accident when
he started playing the piano for the first time, and discovered a musical genius he never knew
The precise neuroanatomical mechanism for gaining this privileged access is not yet
resolved.An earlier study in 1970. found that autistic savants with exceptional artistic,
mathematical and memory skills have damaged the left hemisphere of the brain. Researchers
Snyder and Mitchell (1999) argued that savant skills reside within everyone, but that they are
not normally accessible to conscious awareness. They theorized that it may be associated with
an atypical hemispheric imbalance wherein concept networks are bypassed or inhibited.
Moreover, some interesting recent reports from San Franciscan neurologist Dr. Bruce Miller
indicate "savant like" abilities in older people with front temporal dementia.
The reason why some autistic and disabled individuals have savant abilities is not yet
completely understood, however, the strong link with autism offers a good starting point for
all future studies.
Neuroimageing has successfully painted the picture of our brain, but has it also
captured a glimpse of our personality at the same time? By making a hidden visible, brain
imaging has made an enormous impact in science, and a large contribution to the
world.Human understanding mysterious brain ways has traveled a great journey, and
significantly evolved to this point where we are today. And even though it seems that we now
know ourselves, there is still much to learn. In fact, it is highly questionable whether a human
PERSONALITY AND THE BRAIN. CAN BRAIN DAMAGE CHANGE PERSONALITY? 9
brain can adequately understand itself, because it has to understand not only the enormous
complexities and dynamics of its biological, electrochemical and structural processes, but also
its temporal interactions with the surrounding environment, the world, and the society at
Science has helped us get a sense of what is going on in our heads, through decades of
researches and studies. It has given us a much clearer picture of the relationship between the
brain and our personality, and made us realize the magnitude of its role in our behaviour. The
neurobiological domain is one of brains and physical causes; the psychological domain is one
of people and their motives. Both are essential to a full understanding of why we act as we do.
Neuroscience has found many missing pieces of the brain puzzle. However, this puzzle is still
incomplete, and new questions arise every day. The brain and the mind are different
frameworks for explaining human experience. And the relationship between them holds
crucial information on how we think about human nature, the ways to deal with ours and
others' imperfections, as well as to enhance the quality of life.It is our privilege and duty, to
use that information, and strive for our very own best.
Aspinwall, L.G., Brown, T.R., Tabery, J., (2012). The Double-Edged Sword: Does
Biomechanism Increase or Decrease Judges' Sentencing of Psychopaths?, Science: Vol. 337
no. 6096 (pp. 846-849), DOI: 10.1126/science.1219569. Retrieved October 24, 2013, from
Barrash, J., Tranel, D., & Anderson, S. (2000). Acquired personality disturbances
PERSONALITY AND THE BRAIN. CAN BRAIN DAMAGE CHANGE PERSONALITY?
associated with bilateral damage to the ventromedial prefrontal region. Developmental
Neuropsychology, 18, 355–381.
Birbaumer, N., Veit, R., Lotze, M., Erb, M., Hermann, C. i Grodd, W. (2005). Deficient Fear
Conditioning in Psychopathy: A Functional Magnetic Resonance Imaging Study. Archives of
General Psychiatry, 62 (7), 799-805.
Blair, R. J. R., Mitchell, D. G. V. i Blair, K. (2005). The psychopath: Emotion and the brain.
Blair, R.J.R. (2006). The subcortical brain systems in psychopathy: The amygdale and
Ciaramelli, E., Muccioli, M., Ladavas, E., & di Pellegrino, G. (2007). Selective deficit in
personal moral judgment following damage to ventromedial prefrontal cortex. Social
Cognitive and Affective neuroscience, 2, 84-92
Davison, K.R., Scherer H.H., Goldsmith (Ur.), Handbook of affective sciences (904-929).
New York: Oxford Press.
Derek Amato, Denver Man, Becomes Musical Genius After Head Injury. Retrieved October
23, 2013, from http://www.huffingtonpost.com/2012/06/07/derek-amato_n_1577768.html
Glenn, A. L., Raine, A., Schug, R. A., Gao, Y. i Granger, D. A. (2011). Increased testosterone
to cortisol ratio in psychopathy. Journal of Abnormal Psychology, 120, 389-399.
Hemphill, J., (1998). Psychopathy, Criminal History, and Recidivism. Retrieved October 24,
Levenston, G.K., Patrick, C.J., Bradley, M.M. i Lang, P.J. (2000). The psychopath as
observer: Emotion and attention in picture processing. Journal of Abnormal Psychology, 109
PERSONALITY AND THE BRAIN. CAN BRAIN DAMAGE CHANGE PERSONALITY?
Malden, Blackwell, Hiatt, K.D., Newman, J.P. (2006). Understandin psychopathy: The
cognitive side. U: C.J.
Monterosso, J., Schwartz, B., (2012). Did Your Brain Make You Do It?. Retrieved October
24, 2013, from http://www.nytimes.com/2012/07/29/opinion/sunday/neuroscience-and-moral-
Newman, J.P. i Lorenz, A.R. (2003). Response modulation and emotion processing:
Implications for psychopathy and other dysregulatory psychopathology. U: R.J.
Patrick (Ur.), Handbook of the psychopathy (296-312). New York: Guilford Press.
Patrick (Ur.), Handbook of the psychopathy (156-171). New York: Guilford Press.
Snyder, A., (2009). Explaining and inducing savant skills: privileged access to lower level,
less-processed information, doi: 10.1098/rstb.2008.0290. Retrieved October 23, 2013, from
Terburg, D., Morgan, B., & van Honk, J. (2009). The testosterone-cortisol ratio: A hormonal
marker for proneness to social aggression. International Journal of Law and
Psychiatry, 32, 216-223.
The primary NIH organization for research on Brain Diseases is the National Institute of
Neurological Disorders and Stroke (2013,October 23). Retrieved October 23, 2013, from
Van Honk, J., Harmon-Jones, E., Morgan, B. E., Schutter, D. J. L. G. (2010). Socially
explosive minds: The triple imbalance hypothesis of reactive aggression. Journal of
Personality, 78, 67-94.
Veit, R., Lotze, M., Sewing, S., Missenhardt, H., Gaber, T., Birbaumer, N. (2010). Aberrant
social and cerebral responding in a competitive reaction time paradigm in criminal
psychopaths. NeuroImage, 49, 3365-3372.
PERSONALITY AND THE BRAIN. CAN BRAIN DAMAGE CHANGE PERSONALITY?
Yang, Y., Glen, A., & Raine, A. (2008). Brain Abnormalities in Antisocial Individuals:
Implications for the Law. Behavioral Sciences and the Law, 26, 65–83.
Yang, Y., Raine, A., Narr, K.L., Colletti, P., Toga, A.W., (2009, September). Localization of
Deformations Within the Amygdala in Individuals With Psychopathy.; 66(9): 986–994.
doi: 10.1001/archgenpsychiatry.2009.110. Retrieved October 23, 2013, from