Subtypes explain why people of the same type may seem quite different from one another.  And lines and wings explain why a type may behave in a manner that seems out of character in certain situations — particularly when they are highly stressed.

27 Subtypes. Three primary biological-survival instincts or drives, exist in all of us — self-preservation, social and one-to-one.  As we grow and develop, one of these survival instincts becomes dominant, and we rely upon it. When this dominant instinct merges with our primary Enneagram type, a character structure emerges which is called our sub-personality or sub-type. This merger can explain variations in traits and behaviors among people of the same Enneagram type.  27 total subtypes exist — three sub-types for each of the 9 Enneagram types.

Lines. On the Enneagram diagram, each type is linked to two other types. This connection is depicted on the diagram as a line or arrow. These lines signify movement and demonstrate how types may shift away from their primary type and toward a separate type under particular circumstances. One example:  A type 2 who is usually pleasant and understanding when relaxed may “move via the line” to type 8 under stress and exhibit the negative characteristics of type 8 by becoming blunt, demanding and even confrontational.

Wings. On the Enneagram diagram, each type is adjacent to two other types called wings. These neighboring types may influence a person’s primary type by adding some of the traits and behaviors of that wing type. Every individual is unique and one wing may be more influential than the other.