Sociology Index

ASSUMPTION OF DISCRIMINATING TRAITS

The view that offenders are distinguished from non-offenders by, for example, their high levels of impulsivity and aggression. There is actually an assumption of discriminating traits. Traits are distinguishing qualities or characteristics of a person. Traits are a readiness to think or act in a similar fashion in response to a variety of different stimuli or situations.

In general, trait theory assumes that people differ on variables or dimensions that are CONTINUOUS. People are seen to differ in the AMOUNTS or QUANTITIES of a characteristic rather than differ in the QUALITY of their characteristics.

The term trait has several meanings:
Generically, it refers to a characteristic or property of some entity. 
In biology, trait refers to features of organisms. 
In psychology, it refers to a component of personality as defined by Trait theory.

Trait Theories of Personality - Dr. C. George Boeree
A trait is what we call a characteristic way in which an individual perceives, feels, believes, or acts. When we casually describe someone, we are likely to use trait terms: I am, for example, somewhat of an introvert, a pretty nervous person, strongly attached to my family, frequently depressed, and (if I do say so myself) very intelligent. I have a good sense of humor, fond of languages, very fond of good food, not at all fond of exercise, and a little obsessive. You see: I have just given you ten traits that actually go a long way towards describing me! 
Psychologists, especially personologists, are very interested in traits. They are especially interested in finding which traits are broad and possibly genetically based, as opposed to ones that are rather peculiar and change easily.

Personality Traits: Idiographic vs. Nomothetic
However the whole issue of whether a trait exists in all people to a greater or lesser degree is complicated by different views of the trait perspective. 

There are two different views as to whether all traits exist in all people:

Idiographic: people have unique personality structures; thus some traits (cardinal traits) are more important in understanding the structure of some people than others 

Nomothetic: people's unique personalities can be understood as them having relatively greater or lesser amounts of traits that are consistently across people (e.g., the NEO is nomothetic) 

The Idiographic view emphasizes that each person has a unique psychological structure and that some traits are possessed by only one person; and that there are times when it is impossible to compare one person with others. This viewpoint also emphasizes that traits may differ in importance from person to person (cardinal, central and secondary traits). It tends to use case studies, bibliographical information, diaries etc for information gathering. 

The Nomothetic view, on the other hand, emphasizes comparability among individuals but sees people as unique in their combination of traits. This viewpoint sees traits as having the same psychological meaning in everyone. The belief is that people differ only in the amount of each trait. It is this which constitutes their uniqueness. This approach tends to use self-report personality questions, factor analysis etc. People differ in their positions along a continuum in the same set of traits. 

Most contemporary psychologists tend towards a nomothetic approach (and the trait approach is often viewed solely as a nomothetic approach these days), but they are aware of how a trait may be slightly different from person to person in the way that it is expressed. 

Some examples where the term 'discriminating traits' have been used:

"All human bodies have the same basic proportions. Our height measures on the average 2.9 times the length of our thigh. Anthropometry has shown that one person can be distinguished from another with great precision when the measurements are derived from sufficiently discriminating traits." 

"At 88% average accuracy, the most discriminating traits in whites were pubic bone shape and subpubic concavity form," - Patriquin M.L.; Loth S.R.; Steyn M. - in a paper on "Sexually dimorphic pelvic morphology in South African whites and blacks."

"In year 1, the project will identify highly discriminating traits between separate samples of Spanish-speaking Latino children three to nine years old with and without learning disabilities and with and without emotional disabilities, in order to determine how to recognize these disabilities in a 90- to 120-minute period."

"When such adaptations evolve, the discriminating traits are sexually selected for their signal value (as well as selected for functions they had prior to being valued by mate choosers)." - Steven W. Gangestad - From "Toward an Evolutionary Framework For Conceptualizing Social Inference Processes."