Get someone to commit to a small action or belief, then leverage that commitment to pull them toward progressively larger commitments that eventually serve the manipulator's goals.1
Pattern:
Example: Cult recruitment: first meeting is innocent discussion, next is "just come to one event," then living arrangements, then financial contribution, eventually severing outside relationships.
Example: Romantic exploitation: first date is innocent, then "real commitment," then "prove your love by X," escalating to increasingly harmful requests.
Example: Professional: small project on the side, then taking on lead role, then accepting lower pay for "the team," then staying in toxic environment because you've invested your identity.
Humans want to be consistent. Once you've taken a public position or made a commitment, contradicting it feels like:
The escalation works because each step seems small and consistent with the previous step. By the time the target recognizes they're in a harmful situation, they've made so many commitments that leaving contradicts their entire self-image.
Sunk-Cost-Fallacy: Sunk Cost Fallacy — Escalation works by building up sunk costs that make quitting feel like waste.
Manipulator-Archetypes: Manipulator Personality Archetypes — The Calculating Manipulator specializes in escalation.