By the way, why lasers versus night sights? The above points about night sights are good and valid ones and well spoken. These are important considerations. The issue of instinct is also major. The natural --and intense-- tendency from within a fight-or-flight neurological state is to focus on the threat. That is instinctually driven. From within that hard-wired neurological state (fight-or-flight), one must overcome one's original instincts to some extent in order to make good use of the sights. That may require more training than many of us realize.
Then we have to keep that edge. Trained-in reactions will begin to erode back towards the original instinctive response when neglected for only a relatively short time. We begin to "lose the edge."
Laser sights are a bit more natural for those of us who can't always train enough to keep that edge.
The other part I've thought out is the reason for the deterrent effect of lasers. I am going to go off on theory here, so those of you who don't have your boots on may want to bail to avoid having to wade through it. (Apologies in advance, and thanks to those who read on. Some or likely all of it I'm sure you know already, but I appreciate your indulging my thoughts.)
A predator in the street has, in the moment,a particular mindset that perceives the "victim" as an animal sees prey. There is a process of re-evaluation that must happen for the predator to let go of that mindset. It may happen very quickly, and internally, but it must happen before the predator behavior will change.
Unless they have a true death wish (--and although that is certainly possible, especially these days, it is a different subject--), a predator that continues its attack has simply failed to perceive the danger to itself as "real" enough to break up that predator mindset. We all have heard of events where the predator hesitated before breaking off an attack, or even continued the attack in spite of the "victim" being an armed defender, and (hopefully) was physically stopped.
When a predator sees that a defender has a gun, the potential of a bullet actually entering the predator's body is a couple of logical steps away. The predator may think of the defender missing or failing to shoot, and these may seem as real to the predator in the moment as getting shot. When a predator sees a gun and at the same time sees a red dot over its heart, those steps are short circuited. The predator is immeditely forced to visualize the bullet entering its body, rather than think around that consequence. That image crowding into the predator's mindset may seem more "real" and imminent than other possibilites.
Ok, what do you think? By the way, thanks for hanging on. I promise that I will not post or post very short for a while to balance that off. ---doug