An internal trigger comes from within the person. It can be a memory, a physical sensation, or an emotion. For example, if you're exercising and your heart starts pounding, the sensation might remind you of a time you were running from an abusive partner.

Marketers use this to make people imagine an event in your past and then offer you a solution.

For example: “Remember that last time when you were out in public when you felt anxious because of your severe acne? People ignored who you were but kept staring at your pimples.” With the above sentence, I made the reader evoke past experiences while sitting comfortably at their home, then I can go on to offer the solution.

Guy is scared of dogs because of a past event.