Your Brain in Relationships

Dan Siegel, clinical professor of psychiatry at the UCLA School of Medicine, has created a “hand model of the brain” to help explain how our nervous system reacts during times of stress. Couples’ therapist often utilize this simple, visual aide to help partners understand what happens in their brain during conflict. 


Step 1: The Hand as the Brain 

Your brain in a relationship
  • Hold up your hand and fold your thumb across your palm.

Your thumb represents the limbic system—the emotional center of the brain, including the amygdala.

  • Now fold your fingers down over your thumb.

Your fingers represent the prefrontal cortex—the “thinking” part of the brain that helps you regulate emotion, empathize, and make thoughtful decisions.

  • When the fingers are folded down, your “whole brain” is integrated—you can think, feel, and connect at the same time.

Step 2: Flipping Your Lid

When we feel threatened, criticized, dismissed, or unsafe in a relationship, our nervous system can go into survival mode. The amygdala (thumb) senses danger and takes over before the rational prefrontal cortex can step in.

  • In Siegel’s terms, we “flip our lid” — our fingers lift up, symbolizing the loss of access to the thinking brain.
  • What’s left in charge is the reptilian brain (the brainstem), responsible for basic survival responses: fight, flight, freeze, or fawn.

Step 3: The Reptilian Brain in Relationships

In moments of relational conflict or emotional disconnection:

  • The reptilian brain interprets a partner’s tone, facial expression, or withdrawal as a threat to safety or belonging.
  • Instead of responding thoughtfully, the body reacts automatically:
    • Fight: arguing, blaming, getting defensive.
    • Flight: withdrawing, shutting down, avoiding.
    • Freeze: going blank, unable to speak or act.
    • Fawn: appeasing, over-accommodating to restore connection.

These are biological survival strategies, not character flaws. The nervous system is simply trying to protect us from perceived danger.

Step 4: Returning to Integration

When partners learn to recognize when their lids are flipped, they can pause, breathe, and use self-soothing techniques to re-engage the prefrontal cortex.

Only after calming the body can they return to curiosity, empathy, and communication—the hallmarks of relational safety and connection.