J. Life Sci. Biomed. 6(2): 33-36, Mar 30, 2016

JLSB

Journal of

ISSN 2251-9939

Life Science and Biomedicine

Biological Basis of Personality: A Brief Review

Mina Khatibi^and Farhad Khormaei

¹PhD Student, Department of Educational Psychology, School of Education and Psychology, Shiraz University, Shiraz, Iran

²PhD, Associate Professor of Psychology, School of Education and Psychology, Shiraz University, Shiraz, Iran

ABSTRACT: This brief review discusses the research on biology-based personality and personality theories

with biological basis. These theories include Eysenck's three factor model of personality, Gray's reinforcement

sensitivity theory, and Cloninger’s model of personality. The biology-based personality research is a relatively

new topic in the field of psychology and there is a lot of scope for further research in the future specially in the

field of neuroscience. Although it is a relatively new topic, but growing in interest and number of publications.

Only recently in August 2004, there was a conference specifically on this topic, called “The Biological Basis of

Personality and Individual Differences”. This was a good forum for presenting and sharing of ideas between

psychologists, psychiatrists, molecular geneticists, and neuroscientists. Recently it was named as the field of

'Personality. Therefore, further research on the biological basis of personality, especially in the field of

'Personality Neuroscience' is recommended.

Keywords: Biology-based Personality, Personality Theories, Personality

INTRODUCTION

Biological Basis of Personality

Personality is derived from the Latin word, persona, where it originally referred to a theatrical mask [1].

The study of personality started with Hippocrates' four humors and gave rise to four temperaments [2].

Personality is the dynamic organization within the individual of those psychophysical systems that determine his

characteristics behavior and thought [3]. Weinberg and Gould [4] defined personality as the characteristics or

blend of characteristics that make a person unique. The American Psychological Association defines personality

as individual differences in characteristic patterns of thinking, feeling, and behaving [5].

The study of personality focuses on two broad areas: [1] understanding individual differences in particular

personality characteristics, such as sociability or irritability and [2] understanding how the various parts of a

person come together as a whole [5].

Biological Basis of Personality

The biological perspective on personality emphasizes the internal physiological and genetic factors that

influence personality. It focuses on why or how personality traits manifest through biology and investigates the

links between personality, DNA, and processes in the brain. It is primarily accomplished through correlating

personality traits with scientific data from experimental methods such as brain imaging and molecular genetics

[6].

The biological basis of personality is the theory which states that the anatomical structures located in the

brain contribute to personality traits. This is derived from neuropsychology, a branch of science which studies

how structure of the brain is related to various psychological processes and behaviors. For instance, in human

beings, the frontal lobes are responsible for foresight and anticipation, and the occipital lobes are responsible for

processing visual information. In addition, certain physiological functions such as hormone secretion also affect

personality. For example, the hormone testosterone is important for sociability, affectivity, aggressiveness, and

sexuality [7]. Other studies also show that the expression of a personality trait depends on the volume of the brain

cortex it is associated with [8].

Personality neuroscience involves the use of neuroscience methods to study individual differences in

behavior, motivation, emotion, and cognition. Personality psychology has contributed much to identifying the

important dimensions of personality, but relatively little to understanding the biological sources of those

dimensions. However, the rapidly expanding field of personality neuroscience is increasingly shedding light on

this topic. DeYoung [8] provided a survey of progress in the use of neuroscience to study personality traits, based

To cite this paper: Khatibi M and Khormaee F. 2016. Biological Basis of Personality: A Brief Review. J. Life Sci. Biomed. 6(2): 33-36.

Journal homepage: www.jlsb.science-line.com

on the Big Five dimensions: extraversion, neuroticism, agreeableness, conscientiousness, and openness or

intellect.

The biological approach to personality has also identified areas and pathways within the brain that are

associated with the development of personality. A number of theorists, such as Hans Eysenck, Gordon Allport, and

Raymond Cattell, believe that personality traits can be traced back to brain structures and neural mechanisms,

such as dopamine and serotonin pathways [6]. One of the best known biological theorists was Hans Eysenck, who

linked aspects of personality to biological processes. Eysenck argued that introverts had high cortical arousal,

leading them to avoid stimulation. On the other hand, he believed that extroverts had low cortical arousal, causing

them to seek out stimulating experiences [9].

The emphasis is placed on the biochemistry of the behavioral systems of reward, motivation, and

punishment. This has led to a few biologically based personality theories such as Eysenck's three factor model of

personality, Grey's reinforcement sensitivity theory, and Cloninger's model of personality. The Big Five model of

personality is not biologically based, but still some studies provided biological support for this model [10]. The

most influential scientists in the field of biology-based personality theories are Hans Eysenck and Jeffrey Alan

Gray. Eysenck used both behavioral and psychophysiological methodologies to test and develop his theories [11].

History of Biology-based Personality Research

It has been, since the ancient Greek time, attempted to explain personality through spiritual beliefs,

philosophy, and psychology. Historically, studies of personality have traditionally come from the social sciences

and humanities, but in the past two decades neuroscience has begun to be more influential in the understanding

of human personality [12]. Eysenck published a book called “Dimensions of Personality,” describing the

personality dimensions of extraversion and neuroticism. He has many publications in this field [13-18]. Gray, his

student, studied personality traits as individual differences in sensitivity to rewarding and punishing stimuli [11].

The significance of Gray's work and theories was the use of biology to define behavior, which stimulated a lot of

subsequent research [19].

The biology-based personality research is a relatively new topic and recently, in 2004, there was a

conference entitled “The Biological Basis of Personality and Individual Differences”. This resulted in the

publication of a book “The Biological Basis of Personality and Individual Differences” [20].

Personality Theories with Biological Basis

The following theories of personality have a biological basis. It will provide, in addition, a biological support

for a popular non-biologically based personality theory, the Five Factor Model.

Eysenck's Three Factor Model of Personality: It was based on activation of reticular formation and limbic

system in the brain [21]. The reticular formation is a region in the brainstem that is involved in mediating arousal

and consciousness. The limbic system is involved in mediating emotion, behavior, motivation, and long-term

memory. The three factors are extraversion (interaction with people), neuroticism (emotional instability), and

psychotism (aggression and interpersonal hostility) [11].

Gray's Reinforcement Sensitivity Theory: This theory is based on the idea that there are three brain

systems that all differently respond to rewarding and punishing stimuli [11]. These are (a) fight-flight-freeze

system which mediates the emotion of fear (not anxiety) and active avoidance of dangerous situations. The

personality traits associated with this system is fear-proneness and avoidance; (b) behavioral inhibition system

which mediates the emotion of anxiety and cautious risk-assessment behavior when entering dangerous

situations due to conflicting goals. The personality traits associated with this system is worry-proneness and

anxiety; and (c) behavioral approach system which mediates the emotion of anticipatory pleasure, resulting from

reactions to desirable stimuli. The personality traits associated with this system are optimism, reward-

orientation, and impulsivity [11].

Cloninger Model of Personality: It is based on the idea that different responses to punishing, rewarding, and

novel stimuli are caused by interaction of three dimensions: (a) novelty seeking which deals with the

impulsiveness of people and is correlated with low dopamine activity; (b) harm avoidance which deals with the

anxiousness of people and is correlated with high serotonin activity; and (c) reward dependence which deals

with the approval seeking of people and is correlated with low norepinephrine activity (20).

Five Factor Model of Personality: It describes five core traits that a person possesses: (a) openness

(enjoyment after experiencing new stimuli); (b) conscientiousness (dutiful and goal-oriented); (c) extraversion

(people who seek stimuli outside of themselves); (d) agreeableness (aim to cooperate and please others); and (e)

neuroticism (people who are emotionally unstable) [10; 22].

To cite this paper: Khatibi M and Khormaee F. 2016. Biological Basis of Personality: A Brief Review. J. Life Sci. Biomed. 6(2): 33-36.

Journal homepage: www.jlsb.science-line.com

Hegerl et al. [23] in an article entitled “Sensory cortical processing and the biological basis of personality”

concluded that their results support the concept that the serotonergic brain system, which is supposed to

modulate sensory processing in primary auditory cortices, is an important factor underlying individual

differences in sensation seeking. Action-oriented personality traits such as sensation seeking, extraversion, and

impulsivity have been related to a pronounced amplitude increase of auditory evoked scalp potentials with

increasing stimulus intensity [23]. The biological approach to personality has also identified areas and pathways

within the brain, as well as various hormones and neurotransmitters, that are associated with the development of

personality [6].

CONCLUSION AND RECOMMENDATIONS

As mentioned earlier, the biology-based personality research is a relatively new topic in the field of

psychology and there is a lot of scope for further research in the future specially in the field of neuroscience.

Although it is a relatively new topic, but growing in interest and number of publications. Only recently in August

2004, there was a conference specifically on this topic, called “The Biological Basis of Personality and Individual

Differences”. This was a good forum for presenting and sharing of ideas between psychologists, psychiatrists,

molecular geneticists, and neuroscientists. A book entitled “The Biological Basis of Personality and Individual

Differences” was later on published [22]. Recently, DeYoung has gone further to name it as the field of 'Personality

Neuroscience' [8].

Therefore, further research on the biological basis of personality, especially in the field of 'Personality

Neuroscience' is recommended.

Competing interests

The authors declare that they have no competing interests.

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To cite this paper: Khatibi M and Khormaee F. 2016. Biological Basis of Personality: A Brief Review. J. Life Sci. Biomed. 6(2): 33-36.

Journal homepage: www.jlsb.science-line.com