Intermittent Reinforcement is a tactic the narcissist uses whereby they randomly intersperse kindand caring behaviors (i.e., rewards) with cruel or indifferent treatment or punishment.
This lack of predictability in the relationship is incredibly addictive to the narcissist's target, who is starved for attention and affection and the good feelings that once existed. Because the "highs" of the good times are so intoxicating, the victim tolerates increasingly abusive behavior.
Narcissistic relationships generally have a hot/cold, push/pull dynamic with the victim holding out during the bad times in hopes that the next morsel of kindness is just around the corner. Needless to say, these morsels become increasingly infrequent as the relationship progresses. That's part of the abuse.
Over time, the victim becomes increasingly dependent on the narcissist, which makes leaving the relationship incredibly difficult:
"What if there's a lasting reward just around the bend?" (There isn't.)
"What if someone else gets all the "good stuff?" (They won't.)
"What if this is just a phase and if I hang in there things will go back to the way it was?" (It isn't and they won't.)
Intermittent reinforcement is one of the major drivers of trauma bonding, creating a strong pull for the victim to remain in a toxic and abusive relationship. Seeing this manipulative pattern for what it is, seeking support, firming up one's boundaries, and focusing on one's self-care will help to break free from this addictive pattern. Because a few morsels do not make a meal!