The definition of a scientific theory is a set of related assumptions that allows scientists to use logical deductive reasoning to formulate testable hypotheses (Feist & Feist, 2009). This simply means that a theory has more than one related assumption, permits a flow of deductive reasoning, and is measurable. A hypothesis is a testable educated guess or prediction more specific than theories. Theories or personality are created by scientific means and the researchers are generally psychologists or from a related field. That being the case, it is not so clear as to why there are so many theories related to personality. The main assumption for the reasons for this is that every researcher comes from their own personal point of view, has their own personal experiences, and unique manner of looking at the world. These theories of personality grow from each unique personality. A science has grown from this uniqueness in theorists called the psychology of science where the individual theorist’s psychological processes and personal characteristics are investigated.
The approaches used to study personality all start with a theory that must generate hypotheses that can be researched and will have verifiable research data. A useful theory will (1) generate research, (2) is falsifiable, (3) organizes data, (4) is internally consistent (5) guides action, and (6) is parsimonious (Feist & Feist, 2009). Generating research includes both directive research that is concerned with the measurement, labeling, and building blocks of the theory and hypothesis testing that leads to indirect validation of the usefulness of the theory. Falsifiable simply means it supports or does not support its major points. To organize data the research must have some identifiable framework. To be internally consistent a theory must be consistent within itself in which the pieces are compatible. The theory that guides action is useful across disciplines and generates structure for finding answers to other problems. Parsimonious is loosely defined as the simpler approach if faced with two theories similar in all of the above ways. To be the most successful in developing a theory of personality, one must begin on a limited scale and expand as warranted. Although it is necessary to generate data with a theory, it is as necessary to observe when dealing with personality. Observation includes all aspects of human personality and is often also measured using testing such as standardized assessment tests.
Testing such as personality inventory tests can reveal to a researcher answers to a basic question in regard to a particular trait or characteristic. As with theories and any other research, these tests must be considered reliable. A reliable test must generate consistent results every time it is given. It must also have validity. Does the test measure what needs to be measured? Personality theorists look for two types of validity, construct, and predictive. There are three types of construct validity. Convergent validity is achieved by the test possessing convergent scores with other valid tests that measure the same construct, such as sociability when looking at extroversion. Divergent validity works the opposite in that measurements do not relate to other valid tests. Discriminate validity is achieved when testing for a specific construct, such as extroversion, and the scores are higher for extroverts than for those known to be introverts. A second component of validity is the predictive validity that tests for some future behavior. Known behaviors are scored and predictions made based upon those behaviors and how they will be the same or different in the future. Knowing how theories are formed and identifying measurement tools are important for understanding how theories are formed and tested but what of individual differences and the factors that may influence personality development in the first place.
It has been said there are no two people alike, and this certainly holds true for personalities. Our personalities are a culmination of our experiences, knowledge, traits, upbringing, and any number of other factors. Some of the major influences on personality are environment and genetics, or nature versus nurture. Even twins raised in the same household have differing personalities, and this difference is often what the personality psychologist hopes to define. No two people experience an event the same way; each has a unique viewpoint, a different knowledge base, emotions, and reactions. The outer face one presents to the world can often be entirely different from the one experienced inside. Our upbringing, religion, social status, body image, self-esteem, environment, genetic makeup, and experiences in life all play a part in influencing our personality.
As shown, defining personality is not an easy task. Harder still is the task of identifying where personality comes from, why it is so different for everyone and how to prove it exists. Many theories have been generated using a baseline model for theories, but even those are subject to the individual viewpoints and personalities of the theorists. Testing can generate only so much information, observation and interviews perhaps more, so the task of finding where personality comes from and how it manifests itself remains aloof. Influences on individual personalities come from every aspect of life and pinpointing the direct correlation to a behavior can be difficult, if not impossible. The personality we show the world is our behaviors constructed from our genetics, experiences, environment, and many other factors to create the unique individual who we are.
References
Feist, J., & Feist, G. (2009). Theories of personality (7th ed.). New York: McGraw Hill.