Bell-Shaped Distribution of Personality Traits

Synonyms

Normal curve

Definition

A symmetrical, unimodal distribution of individual differences along a personality trait dimension.

Introduction

The distribution of most normal personality traits tends to have a more or less symmetrical, bell-shaped form. Such a distribution has a single mode, its mean is very close to its median, the majority of individuals congregate in the vicinity of the mean and median, and relatively few individuals fall in the two tails. Bell-shaped distributions are sometimes incorrectly equated to the normal (Gaussian) distribution, but that distribution is only one form that bell-shaped distributions can take. For instance, non-Gaussian bell-shaped distributions include the logistic and Student’s t distributions, and they may differ from the normal curve in being narrower with heavier tails (leptokurtic) or flatter with fewer extreme outliers (platykurtic).

The processes that give rise to bell-shaped distributions are consistent with what is known about the...