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The factorial-biological theory of the personality of Jeffrey Gray

The factorial-biological theory of the personality of Jeffrey Gray

December 1, 2022

The personality theory of Gray is framed in the biological and factorial paradigms ; This means that it explains the differences between individuals based on variables related to the nervous system and that it is based on the grouping of different personality traits in higher dimensions through statistical analysis techniques.

In this article we will analyze the main aspects of Gray's model. Specifically, we will focus on the two basic personality factors and the two associated physiological mechanisms that this author described: Anxiety and the mechanism of behavioral inhibition and impulsivity and the behavioral approach.


  • Related article: "The main theories of personality"

The personality theory of Jeffrey Gray

The British psychologist Jeffrey Alan Gray (1934-2004) presented in 1970 his factorial-biological theory about the structure and bases of interindividual differences in personality; according to the model, these are due to biological mechanisms that relate to reactions to reinforcement, to punishment or to stimuli and novel situations.

In this sense Gray described two main biological mechanisms that determine behavior trends. He named one of them "behavioral approach mechanism" and the other "mechanism of behavioral inhibition"; These would be equivalent to the basic factors of personality, which would have a physiological basis.


The personality theory of Gray is based largely on the Pys model of Eysenck , which defines three major biologically determined personality factors: neuroticism, extraversion and psychoticism. However, there are significant differences between the two theories that are worth commenting on; we will stop at them later.

So, Gray proposes Two basic dimensions of personality: anxiety and impulsivity . The first combines the introversion and neuroticism of the Eysenck model; on the other hand, a high level of impulsivity would also imply a high neuroticism, but in this case it would be associated with extraversion. Each dimension corresponds to a behavioral mechanism.

  • Maybe you're interested: "The Eysenck Personality Theory: the PEN model"

Anxiety and the mechanism of behavioral inhibition

According to Gray's description, anxiety is a combination of neuroticism (or emotional instability) and introversion. In the Eysenck model, extraversion is characterized by personality traits such as activity, dominance, assertiveness, sociability and the search for sensations, and introversion would be its opposite.


The mechanism of behavioral inhibition, which is associated with this primary dimension of personality, is mainly involved in the avoidance of unpleasant situations and stimuli , that is, the punishment. Since it is determined by variables of biological type, the mechanism would be activated to a different degree in each person.

Among the main functions of the mechanism of behavioral inhibition, and therefore of anxiety, we can highlight the response to punishments, the inhibition of obtaining reinforcers in certain circumstances (for example in the delay of reinforcement) and the avoidance of new stimuli. and potentially aversive.

Having a high level of anxiety predisposes the person to experiment frequently frustration, fear, sadness and other unpleasant feelings . Therefore, this feature is associated with the behavioral avoidance of stimuli that are perceived as anxious by the individual.

Impulsivity and the behavioral approach mechanism

The Impulsiveness factor of the Gray model combines high levels in the dimensions Neuroticism and Extraversion of Eysenck. In this case, the relevant biological system would be the mechanism of behavioral approximation, which, when activated, would cause us to behave in a manner opposite to the mechanism of inhibition.

So, in this case premium the obtaining of rewards over the avoidance of punishments . This behavioral system favors the approach to stimuli and novel situations and is activated mainly by the possibility of obtaining a reinforcement, unlike the mechanism of behavioral inhibition, which depends on the punishment.

According to Gray, people with a high level of activity of the mechanism of behavioral approach (or impulsive, if you want to say it in this way) tend to show more positive emotions such as joy. It could be related to the action of the neurotransmitter dopamine , involved in the brain reinforcement system and motivation.

Similarities and differences with Eysenck's theory

The theories of the personality of Eysenck and Gray have obvious similarities; after all, the second author based himself mainly on the work of the first when developing his own model. Both are categorized into two major paradigms of the study of personality: factorial and biological theories.

A key difference between Gray's personality theory and Eysenck's is that the former gives greater importance to physiological responses to different types of stimuli, whereas the PEN model is based mainly on classical conditioning , in the levels of cerebral activation and in the functioning of neurotransmitters.

In any case, these are two complementary theories: since Gray started with the Eysenck model, his factors can be added to those that were described by this author. Each of them explains different aspects of personality, and the features they describe could be explained by different but interrelated biological variables .

Bibliographic references:

  • Gray, J. A. (1970). The psychophysiological basis of introversion-extraversion. Behavior Research and Therapy, 8 (3): 249-266.
  • Gray, J. A. (1981). A critique of Eysenck's theory of personality. In H. J. Eysenck (Ed.), "A model for personality": 246-276.

Trait Theory (December 2022).


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