Temperament and Personality

Another area that has gotten a lot of attention in terms of biological determinants of personality is that of temperament.  

Most parents will tell you that their children exhibit general behaviors very early in their development.  Some may be stubborn, others happy, and still others may be grumpy.  We see these general emotional responses in infants and can often see a trend by the time the child is only a few months old.  Many of these parents will also assert that these responses, or temperaments, seem to continue throughout the child's development.

The stubborn infant who cries when put down for a nap may become the stubborn adolescent who rebels against authority or resists society's norms.  The happy and content infant may be the adult who finds friends easily and has a knack for seeing the good in others.  When these temperaments are present shortly after birth and continue throughout a person's life, it is difficult to not see a biological connection.

EAS Temperament Model

Like Eysenck, other biological theorists were interested in determining how many different temperaments there are.  Statistical techniques such as the Factor Analysis have been applied but with mixed results.  There is one theory, however, that seems to have a stronghold in this area.  Using three dimensions: emotionality, activity, and sociability, the EAS temperament model was developed.

Emotionality refers to a child's emotional reactions to environmental stimuli.  In other words, a child who is highly emotional may cry easily, be more fearful, get excited quickly, or exhibit other strong emotional responses.  A child low on this temperament may seem more easy going, relaxed, and less interested in his or her surroundings.  As an adult, high emotionality may be related to artistic endeavors, relationships, and career choice.

Activity refers to a child's level of energy.  Those high in this temperament are seen as active, prefer physical activity and games, may be more fidgety or difficult to settle down.  As adults, our temperament for activity plays a significant role in our career choice, hobbies and socialization.

Finally, sociability relates to a person's comfort and level of interaction with others.  Obviously those high in this temperament will prefer group activities, team sports, and be more comfortable interacting in social settings.  Those low on sociability may prefer solitary activities and experience anxiety around strangers or new situations.  As adults, it is easy to see how our level of sociability can influence our friendships, careers choice, and hobbies.

Inhibition

Another area of biological research has focused on a child's tendency toward being inhibited or uninhibited.  Research in this area began when two theorists (J. Kagan and H. Moss) set out to observe personality traits of preschoolers and then compare these same traits once their subjects became adults.  This longitudinal case study model revealed that while some traits tend to change, inhibition seemed to remain relatively stable over time.

A plethora of research has been completed to study this phenomenon with relatively similar results.  An inhibited child, one who is wary of strangers, more passive in his interactions with others, and more hesitant to explore new situations, tends to become an adult who who is less likely to engage others, be more passive in relationships, and prefer solitary to group activities.  Those rated as uninhibited similarly show similar characteristics as adults as they did when they were younger.

Some research has even shown physical characteristics to be related to a child and adults level of inhibition.  For example, studies have shown that inhibited and uninhibited children differ in terms of body size, allergies, and even eye color.  This suggests a very strong biological link but leaves open the questions raised earlier: Are we treated differently by others based on our physical appearance?  Do we see ourselves differently based on our physical characteristics?  Is inhibition directly linked to our genes or indirectly through other biological components.  These questions have yet to be answered conclusively.