Theoretical Perspective of the Approach The approach's personality models are grounded on biological models. The models are based on empirical human and animal findings concerning the associations between neurological system functions and personality dimensions. Traits that are measured are reward-dependence, harm avoidance, novelty-seeking etc. The hypothesis is that they are grounded on genetic and neurochemical influences. For instance, sensation-seeking and explorative tendencies like drug usage make use of dopaminergic pathways, and such a characteristic corresponds to novelty-seeking behavior in Tridimensional Personality Questionnaire (TQP). People who are high on the novelty-seeking spectrum tend to be impulsive and take a lot of risks. Serotonin is linked to harm and punishment avoidance. Lower serotonin levels result in a "neurotic" personality. Reward dependence is linked to noradrenaline. People that lean more towards harm avoidance tend to be more affectionate and sentimental. Those on the other end of the scale tend to be pragmatic and tough. Heritable biases are reflected by the personalities and there are a number of traits that correspond to one another. For instance, neuroticism is correlated to harm avoidance while extroversion is correlated with novelty-seeking. This avails evidence for cross-validating measures as regards their ability to capture personalities (In Colarelli & InArvey, 2015).

Eysenck's Personality Theory

Eysnck (1952, 1967, 1982) came up with quite an influential personality model. On the basis of the results from factor analyses of responses, he proposed three personality dimensions: psychoticism, neuroticism, psychoticism and extroversion. Hans Eysenck held the belief that biology was the main determinant of personality. While he may have been controversial in some instances, he is still considered one of the most influential authorities in the subject of personalities (McLeod, 2014). Besides the place of genetics in sculpting personality, Hans also believed that conditioning had a role to play. He believed that personality traits are indeed hierarchical and a small number of the basic traits birthing many more of what are called superficial traits. Differences in physiology that are brought about by genetics make certain individuals prone to behavioral conditioning. Eysenck made the suggestion that introverts could be aroused more physiologically and so they were more prone to conditioning by the stimuli from their environment. Due to this fact, introverts develop many inhibitions, which can make them uneasy or shy in a social place. He held the belief that empirical evidence for the contributions of genetics to personalities is drawn from two main types of studies: heritability studies and the study of temperature (Biological Approaches, n.d). As per Eysenck, neuroticism's two dimensions (unstable vs. stable) as well as introversion-extroversion merge to create different personality characteristics.

Extroverts are more sociable and desire change and excitement. They easily get bored. They are often impulsive, carefree and optimistic.

Introverts tend to be reserved. Their actions are planned and they are in control of their emotions. They are always reliable, pessimistic and serious.

Neurotics / unstables are always anxious, moody and worried. They can be very emotional and find it hard to come down on being upset.

Stables are calm emotionally, are unreactive and not worried.

Eysenck (1966) added a 3rd dimension/trait later on. It was psychoticism. This is not having empathy, being troublesome, aggressive and a loner. Eysenck relates the personalities of individuals to the autonomous nervous system's (ANS) function. Personality depends on what balance exists between the nervous system's inhibition and excitation process. Neurotic's nervous systems tend to respond faster to stress (Biological Approaches, n.d).

Cattell's 16PF Trait Theory

One person that was in disagreement with Eysenck's theory of looking at personality in only three or two behavior dimensions was Cattell (1965). In his argument, he stated that it was of utmost necessity to pay attention to more traits so that a person's personality spectrum could be more accurately evaluated (McLeod, 2014). While Eysenck's theory was based on hospitalized servicemen's responses, Cattel's data had a much wider source.

L-data -- represented life data record like absence from work, school grades etc.

Q-data -- was a questionnaire structured to determine the personality of an individual.

T-data -- data collected from objective tests that are designed to tap into the construct of a person's personality.

The Q-data and T-data were analyzed by Cattell using a certain mathematical technique referred to as factor analysis. He looked into which kind of behaviors tended to be represented in the same individuals. 16 personality traits were identified. They were the factors that were common to all humans. Cattell distinguished source traits from surface traits. The...

Cattell stated that in determining the personality of a person, source traits carried more weight (Biological Approaches, n.d).
Allport's Trait Theory

Allport's theory of personality lays emphasis on an individual's uniqueness as well as the motivational and cognitive processes influencing their behavior e.g. traits, attitudes, skills, habits, temperament and intelligence. Allport (1937) believed that personality is determined at birth by biology and further influenced by the experiences the person has due to their environment (McLeod, 2014). Gordon Allport, as a modern trait theorist, used personality describing words. They described the adjectives that were seen to be a description of the observable and somehow permanent personality traits. He then organized the traits hierarchically in three levels:

Cardinal Traits: They are the main determinants of a person's behavior. They are atop the hierarchy and are known collectively as the "master control" of the individual. They are the person's ruling passions. The traits are quite powerful, but not many people have a personality that is dominated by just one trait. Personalities are often comprised of a number of traits.

Central Traits: They are second to the cardinal traits. They are general characteristics that can be found in various levels in people. They include: grouchiness, wildness, sneakiness, friendliness, agreeableness, kindness, loyalty etc. They form the building blocks with which behavior is shaped.

Secondary Traits: Can be found on the ground floor of the hierarchy and aren't as consistent or obvious as the other traits. They are many and come to the fore under different circumstances. Attitudes and preferences fall under this category. Such are the traits that may make one seem to be behaving incongruously to their other traits. Someone who is often friendly may suddenly become angry when tickled. Someone may be deemed outgoing but feel nervous when speaking to an audience.

Allport's hypothesis was that behavior was influenced by both external and internal factors. He called such forces phenotypes and genotypes. The internal forces are called genotypes, while the external forces are called phenotypes. Phenotypes tend to influence how one sees their surroundings and the influence other individuals have on their behavior (Biological Approaches, n.d).

Freud's Tripartite Theory of Personality

Freud's theory has it that personality encompasses many factors that are Instinctual drives -- sex, unconscious processes, early childhood influences, aggression and sex. Parent's influence was the greatest influence when one is young. His view was that the development of personality depended on the interaction of the environment and instinct during a person's first five years of life. Freud saw personality as structured into 3 parts (tripartite, that is), the id, the ego and the superego (the psyche). The three develop at different stages of a person's life. They aren't physical in any shape or form -- more like systems (McLeod, 2014). The primitive part of a person's personality is the id. It is composed of all biological (inherited) personality components e.g. the sex (life) instinct, aggressive (death) instinct, Eros (containing libido). The id's operation is on the pleasure principle. This is in the realization that each and every wishful impulse ought to be immediately satisfied, regardless of what consequences that might accrue from such decisions and actions. The ego comes up to help mediate the real external world with the unrealistic id. The ego is a person's decision making personality component. Its operation is per the reality principle. It works out realistic means of satisfying the demands of the id. It often makes compromises or delays satisfaction so that negative consequences are avoided. The ego pays attention to the norms and realities of society as well as rules and etiquette when making a decision on which path to take. The superego takes into account morals and values, which a person learns from their parents or members of society. It has similarities with the conscience, which can apply punishment on the ego by feelings like guilt. This approach's assumption is that the determination of behavior is done by quite stable traits that form the core units of a person's personality. Traits influence a person's way of behavior, regardless of circumstances. The implication is that over time, traits ought to be consistent over a range of circumstances, but variations may exist between individuals. The presumption is that individuals have different traits given their different genetics (Biological Approaches, n.d).

Comparison and Contrast

In comparison to Cattell, Eysenck was predisposed to making theories before he collected and factor analyzed any data, extracting fewer factors and using more ways to collect data. Cattell and Eysenck have both made use of factor analysis in identifying traits. The traits…