Gaslighting children prepares them to question their own perceptions and to doubt their own memories. So when someone later in life does the same, the old survival recordings kick in and instead of being steadfast, they are more easily convinced. It's a powerful tendency to be aware of when anyone abuses you in any way and denies it instead of apologizing for causing you harm. People who aren't invested in convincing you that you are wrong about what you experienced with your own senses are generally sorry when they hurt somebody, are willing to listen to the effect of their words and actions, regardless of their intentions, and trying to be a better human.
Gaslighters know they are in the wrong and behaved poorly, but like the cowards they are, they try to convince everyone, especially the victim, that they didn't do the thing they just did. They don't even get as far as, "I didn't mean to." and just stop at "I didn't." Revealingly, these are the most common please of pedos that prey on vulnerable people. It works on their victims that were already trained by parents.
I just posted a great video about how the victims of narcissistic behavior are gaslit every single day when they try to disclose they are being abused.
https://youtu.be/bNDr6ChLhvkDr. Ramani is wonderfully healing to watch.