Personality theory is no different. In the past 40 years personality research has seen at least one full cycle of uncritical enthusiasm turn into bleak pessimism and again to enthusiasm. Recent events suggest that the field is again becoming a focal area of psychological study. Exciting discoveries are being made in behavior genetics, there is a growing consensus about the relationship between personality traits and emotional states, biological theorists of adult personality are exchanging ideas with theorists of childhood temperament, and long term studies of personality development across the life span are delivering on the promises made many years ago. Unfortunately, many promising approaches have led nowhere.
Personality theories attempt to account for individual behavior.
The scope of such theories is vast. They describe how genetic predisposition's and biological mechanisms combine with experience as children develop into young adults who will show behavioral consistencies over their life span. Personality researchers report heritability coefficients, relate MRI scans and EEG activity to intellectual performance and emotional reactions, and predict job outcomes and lifetime satisfaction. They examine the dimensions of self description and the many ways feelings, knowledge, and beliefs combine in behavior. Personality research ranges from tests of evolutionary theories of jealousy to analyses of the structure and content of one's life story.