Instinctual stacking: definition and the six stackings

Ranking the three instincts

Saying "I am sx dominant" names only the first instinct. A stacking adds the rest. The first position is where attention goes automatically. The second is a supporting instinct, used comfortably but less obsessively. The third is the one that tends to get neglected, sometimes to the point of a person not noticing it at all until it causes trouble. Teachers call that last position the blind spot or least preferred instinct.

Where stacking comes from

How people use it

Stacking is often written next to the type, as in 9w1 sp/so. It is especially popular in conversations about relationships, where partners with opposite stackings may feel they are speaking different languages. An sx/so partner might crave late-night intensity while an sp/so partner is thinking about whether the rent is covered and the kids have lunches packed.

The blind spot gets a lot of attention in growth teaching. The idea is that the most neglected instinct is where life tends to surprise you: the so-blind person who did not realize they had alienated colleagues, or the sp-blind person who forgot to see a doctor for three years.

An example

Two Sixes are both loyal and alert to risk. One is sp/so: she keeps an emergency fund, knows the neighbors, and rarely gets swept up in passionate friendships. The other is sx/so: he forms intense bonds, argues hard to test people, and is forever forgetting to renew his car registration. Tradition explains the contrast with stacking.

Research status

Related terms: instinct, the three individual instincts, and subtype.

• Instinct: Enneagram glossary definitionEnneagram instinct, defined: the three basic drives (self-preservation, social, sexual) said to color every type, where the idea came from, and evidence.
• Self-preservation instinct: Enneagram definitionSelf-preservation instinct (sp), defined: the Enneagram drive toward safety, health, comfort and resources, how it shows up daily, and its research status.
• Social instinct: Enneagram definitionSocial instinct (so), defined: the Enneagram drive toward belonging, roles and standing in groups, what it does and does not mean, and the evidence.
• Sexual instinct (one-to-one): Enneagram definitionSexual instinct (sx), defined: the Enneagram one-to-one drive toward chemistry, intensity and deep bonds, why it is not mainly about sex, and the evidence.
• Subtype: Enneagram glossary definitionEnneagram subtype, defined: a type combined with its dominant instinct, giving 27 subtypes such as sp 6 or sx 4, how teachers use them, and the evidence.