Personality is a complex dimension that describes the behavioral, cognitive and emotional pattern of an individual; by which he expresses himself as an independent being within human multiplicity.
The scientific interest in knowing what personality is and how it manifests itself has led many researchers over the years to postulate different theoretical models for this purpose. One of them was Jeffrey Gray, who presented his theory of reinforcement sensitivity as an alternative to classical models (Eysenck, for example), but from a fundamentally neuropsychological basis.
In this article, we will discuss the author’s theoretical postulates, which constitute a very important view of the nature of acts and cognitions, from which we can better understand who we are and why.
Reinforcement sensitivity theory
Reinforcement Sensitivity Theory attempts to explain what a human being looks like from his motivation to approach or move away from environmental stimuli or situations at your disposal.
While it is true that there are a certain number of appetitive stimuli in the face of which innate research unfolds in which learning has not intervened (such as food to nourish us), others have acquired their positive nuances in through individual experience.
The theory considers two types of stimuli: Those which cause an unconditional approach or a rejection (learning shared by the whole species throughout evolution) and those which generate similar responses but as a result of personal experiences (avoidance of dogs because we have had an unpleasant encounter with one of them or because we saw a third party victim of an assault, for example).
The desire for approach and rejection / flight (maintained by motivational states) would depend on the activation / inhibition of a series of neural networks, which would become the organic substrate of the basic dimensions of the personality. From this perspective, what we think, feel or do can be captured by a small group of attributes that have their roots in the brain (offering a parsimonious and clear explanation of behavior from its multiple interactions).
After an in-depth study of neuronal structures, and endowed with a large theoretical background on their functions, Gray proposed three brain systems that would be the basis of approach and distance behaviors.: The behavioral approach system (SAC), the behavioral inhibition system (SIC) and the combat or flight system (SLH). Each person would present a specific activity model for each of them, which would shape the profile of how they act and feel in their natural environment.
Based on these observations, he further proposed two dimensions of personality: anxiety and impulsivity, different from those commonly considered. Each of these would relate to one of the systems examined and also involve different emotional experiences.
As you can see, Gray drew a direct relationship between the brain and the personalityUnderstanding that behavior and thinking can be explained from the activity of structures involved in their systems. In what follows, we will relate these two phenomena, explaining in a simple way how neurology and psychology converge in this interesting integrated theoretical model.
1. The behavioral approximation system (SAC)
SAC is a neurological mechanism that promotes a behavior of approaching positively conditioned stimuli (i.e. associated with desirable outcomes or to avoid adverse consequences), thus motivating active research in its spatial proximity and temporal. Thus, it would be responsible for promoting the availability of what is perceived as desirable or which increases the chances of survival.
All this would result in a voluntary behavior of motor and emotional approach., Intervening by coordinated brain structures. Specifically, the dopaminergic fibers that emerge from the midbrain (ventral tegmental area and nucleus accumbens) to limbic regions such as the basal ganglia, as well as other neocortical type (sensorimotor, motor and prefrontal cortex). The activation of this system would be manifested by positive affects associated with the dimension of impulsivity.
The basal ganglia are responsible for planning and integrating voluntary movement, as well as motivation and emotion, while the motor and sensorimotor zones are necessary to translate everything into explicit approach actions.
The examination is complemented by the function of the frontal lobe (which includes intention and projection at the executive level) and the reward system (which sets a positive tone to the life experience through the production of dopamine).
2. The behavioral inhibition system (SIC)
SIC is understood, within the framework of reinforcement sensitivity theory, as an opposite response to that of SAC. In that case it would be activated in the face of negatively conditioned stimuli (Because they cause damage or prevent something desirable from being achieved), or have been fixed throughout the development of the species as objects or situations to be avoided. This is why they promote behaviors whose end is that of active distancing.
It also extends to new or overly ambiguous situations, in which it is necessary to act in a balanced way and with special attention to the environment. Consequently, the action of approach would be inhibited until a more precise knowledge is made of the nature of the confronted facts, articulating from that moment a series of behaviors of proximity (intervened by the SAC) or d avoidance (intervened by SIC and SLH).
The brain structures that make up the CIS are the hippocampus and its projections to the prefrontal cortex.. The hippocampus is thought to actively participate in memory and spatial orientation, while the prefrontal cortex is responsible for attention and forward thinking. All would coordinate to explore the immediate environment and predict what might happen at this precise moment or as a consequence at a later time.
The system is therefore directly associated with anxiety and is responsible for constantly evaluating (monitoring) the situation in which we are immersed and what could happen in the future, in order to anticipate the appearance of undesirable events that we fear or believe we should avoid.
3. The combat or flight system (SLH)
SLH is linked to the leakage of adverse events of those who are participants (which differentiates it from avoidance) and with fight or flight behaviors.
The brain structures involved are the amygdala (in which various emotional experiences are processed, but in particular fear) and the hypothalamus (which is present in stress responses and in the activation of the autonomic nervous system). Anger and fear would depend on him, emotions meant to prepare the body for an immediate response.
If you know the simultaneous overactivation of this system and the SAC causes an approach and evacuation behavior to explode at the same time and towards the same object, an inconvenience which should be solved by the participation of the SIC. This dissonance between appetite and aversion is thought to be responsible for anxiety as a symptom within a disorder.
How would personality be understood from this model?
To explain the personality according to the theory of the sensitivity to reinforcement, the systems SAC and SIC are notably considered. The two work independently, so that activating high or low of one of them would not influence that of the other. So there would be people with hyperactivation / hypoactivation of both systems, and others in which one is hyperactivated and the other hypoactivated.
As stated above, SAC would be related to impulsivity and SIC would be related to anxiety, these being the dimensions basis of personality according to Gray’s model (thoughts or acts of approach and inhibition respectively). In this sense, subjects with hyperactive SAC would be the impulsive, and those with hyperactive SIC would be the anxious.
some authors have drawn analogies to explain that the activation spectrum of SAC would be associated with continuous extraversion / introversion (tendency to sociability or preference for loneliness or individuality) while SIC would do the same with that of neuroticism / stability ( vulnerability to emotional distress or regularity in affective states).
At present, the theory of sensitivity to reinforcement is the subject of numerous investigations, Hence results both favorable and unfavorable. Some of them suggest that the SAC and SIC systems might be related in some way (so they wouldn’t work independently) and the study of anxiety / depression from this same perspective is also addressed. However, it still takes some time to know the real scope of Gray’s model.
- Bijttebier, P., Beck, I., Claes, L. and Vandereycken, W. (2009). Theory of gray reinforcement sensitivity as a framework for research on personality-psychopathology associations. Journal of Clinical Psychology, 29 (5), 421-430.
- Colder, CR, Trucco, EM, López, HI, Hawk, LW, Read, JP, Lengua, LJ … Eiden, RD (2011). Revised the theory of reinforcement sensitivity and assessment of BIS and BAS laboratories in children. Personality Research Journal, 45 (2), 198-207.