Theoretical Perspective of the Biological Approach to Personality Psychology
Personality is defined as a person's exceptional deviation on the general evolutionary design for human temperament. A personality trait refers to a durable disposition to act in a certain manner in different situations. Personality traits represent some of the most significant sets of individual disparities in organizations. It is the comparatively set of psychological characteristics that differentiates one person from another. People should strive to comprehend fundamental personality attributes and the manner in which they influence a person's behavior (Griffin 2007).Most perspectives to personality presuppose that some traits are more fundamental compared to others. This concept underlie that a small number of basic personality traits determine other, more superficial traits. With respect to the biological approach to personality, personality traits are determined by human genetic inheritance, behavioral tendencies that develop from evolutionary history and human conduct that generate through intricate biological system, such as neurotransmitters and hormones. Although the biological perspective to personality does not highlight a consistent theoretical approach, it entails a collection of factors that links personality to biology, highlight human behavior and personality origin in evolutionary evidence and theory.
The Brain and Personality
The architecture of the brain is significant in understanding personality. The brain is a modular dispensed, self-organizing system of neural networks. Emotional, behavioral and cognitive functioning are mediated through sequential and parallel processing blueprints of networks that originate in divergent structures and dispensed throughout the brain (Carducci, 2009). Within specific sub-cortical and cortical regions, functional capacities are mapped on the brain in a modular dispensed manner. In studying personality and the brain, the interrelations amid three aspects: psychological abilities, the social environment and biological mechanisms are paramount (Carducci, 2009). As a result, an understanding personality development and the brain systems calls for an extensive comprehension of how these systems interact over time. The brain comprises of populations of cells and billion neurons are devoted to the activity of transmitting information between the periphery and different brain structures. The multiple neural pathways offer the flexibility and complexity of behavior.
Neurophysiology and brain anatomy are crucial to personality. The measurement of the activities of the brain through comparatively old methods such as EEG (Electroencephalography), latest methods such as MEG (Magnetoencephalography), TMS (Transcranial Magnetic Stimulation), PET (Positron Emission Tomography), and other major techniques help in enhancing the knowledge concerning the brain (Carducci, 2009). PET and FMRI (Functional Magnetic Resonance Imaging) scanners are used to offer data summaries that determine the regions of the brain that are active during different emotional reactions and mental activities. These techniques are applied to compare brain activities in persons with divergent personality traits.
The Ascending Reticular Activating System (ARAS)
The Ascending Reticular Activating System (ARAS) is the foundation of the introversion and extraversion, and it originates from the central portions of medulla, diencephalon and midbrain. According to Carducci (2009), ARAS is a collection of nerve fibers situated at the bottom of the lower part of the brain and the spinal cord, and it activates the entire brain. The ARAS excites the cerebral cortex cells and reduces incoming stimuli from other sources .ARAS facilitates regulation of arousal level in the brain to allow an individual to operate most efficiently, and it keeps the brain alert. The arousal of the brain increases when a person is excited (Carducci, 2009). However, the brain may direct the ARAS to lower the arousal level under given conditions such as during bedtime. As a result, ARAS can either raise or lower the arousal level depending on the feedback it gets from the brain.
The amygdala is one unit within a system, which is committed to appraising emotion stimuli. The damage to amygdale impairs the judgment of socially crucial facially significant facial expression. PET studies of normal subjects have affirmed the involvement of amygdala in emotional perception. PET Studies show that left amygdala shows more activation when images of fearful faces are shown while the right amygdala is sensitive to happy faces (Andrewes 2001). . People with double-sided damage to amygdala cannot recognize fearful facial expressions although they have no problem recognizing angry facial expressions. The most apparent support for the amygdala as a personality agent is realized from animal research that shows a lesion to the central amygdala leads to tameness, and that a chemical stimulation of the same region leads to behavioral signs of aggression and fear. This type of result is applicable to humans.
Andrewes (2001) highlights analysis of psychosurgery study series that have indicated a reduction in aggression and behavioral disorder in people who have undergone amygdatolomy and amygdalectomy (Andrewes 2001). These patients become more obedient, controllable and calm. In this regard, amygdala plays a crucial role in formulating emotional reaction. When the environment appears to produce imminent dangers, amygdala reacts through making increased heartbeats and increased blood pressure. Attributed linked to amygdala operation include sociability, sexuality, chronic anxiety and fearfulness. Moreover, studies show that the amygdala is receptive to kindling and over-activation of amygdala neurons leads to heightened emotional reactions such as anger, nervousness, panic and paranoia.
The Frontal Lobes And The Neocortex
According to Christos (2003), most of the understanding regarding what different brain parts do is realized from the examination of people who have had some portion of their brain surgically removed because of brain tumor or accident or to manage epilepsy. Scientists have realized that personality and people's ability to plan are located in the frontal lobes. This is because people who have had a huge part of their frontal lobes removed through methods, such as prefrontal lobotomies become zombies following the surgery, devoid of any personality (Christos, 2003). The frontal lobes are part of the neocortex, and the neocortex is the major engine of cognition and self-awareness. The neocortex is portioned into regions based on their functions, motor, association and sensory areas. Each sensory area is situated in diverse regions within the cortex.
Approximately 75% of the neocortex can be grouped as motor or sensory area. This percentage is used in supporting the highest cognitive functions in humans such as theoretical reasoning foresight and language (Christos, 2003). Neocortex is further divided into geographical regions that are further portioned into lobes, parietal, occipital, frontal and temporal. The frontal lobes that form the half of neocortex are found in the front of the brain. Frontal lobes specialize in language functions, personality traits executive control, motor activity and emotionality. Powerful actions in this area happen to persons prone to negative emotions as well as to consistently cooperative people as indicated in FMRI studies (Christos, 2003).
The Anterior Cingulate
The anterior cingulate is the foremost cortical goal for dopaminergic protrusions from the ventral tegmental area. The ventral anterior cingulate is linked to personality traits and it allows people to favor positive personality traits as more descriptive than negative personality traits (Carducci, 2009). The ventral anterior cingulate is linked to decisions of positive personality traits particularly those that are self-descriptive. Studies indicate that ventral anterior cingulate is linked with imagining prospective constructive occurrences compared to future unconstructive events to people who are naturally affirmative (Carducci, 2009). The anterior attentional system gets massive inputs from emotion-linked frontal and limbic circuits thereby offering a means for enhanced attention control. Anxiety-linked impacts on the anterior system as highlighted through a PET study demonstrate activation of the left anterior cingulate cortex. A recent PET study indicates that anterior cingulate is related to downbeat trait anxiety (Carducci, 2009).
Lessons Of Psychosurgery and Brain Systems
The fact that personalities traits are partially caused by genetic aspects imply that there must be a biological impact on attributes encoded within an individual's DNA. The impact of genotype on the brain structure and operation is likely to be influenced through interaction with the setting. Secondly, there is striking evidence for radical personality shift due to brain damage. Damage to cerebral cortex's frontal lobes is notorious for disruption of personality; an individual may become impulsive, aggressive or unstable (Carducci, 2009). Thirdly, there is some proof that attributes correlate with biological indicators of brain functioning such as reactions collected from electroencephalographic and FMRI studies (Carducci, 2009).Correlations between attribute parameters and the brain prompt the need for development of psychobiological theories of personality attributes. Such theories should be able to determine how individual disparities in the specific brain systems functioning influence permanent individual disparities in behavior.
Personality is linked to a mass of divergent brain structures, ranging from primordial systems controlling alertness and wakefulness to systems for higher cognitive functions such as thought and language. To treat personality disorder, psychosurgery is involved and it involves disabling brain regions (Matthews & Whiteman, 2009). Current psychosurgical methods focus on the pathways amid the frontal cortex and the limbic system. Psychosurgery comprises of the surgical ablation or disentanglement of brain tissue to correct abnormal affective and cognitive mental states triggered by psychiatric disorders. Psychosurgery alters dysfunctional brain pathways and circuits, and the process has been refined to a more effectual and safer procedure.