I think CS is on the right track with his evolutionary analysis.
I spend a lot of time alone in Adirondack forests, sometimes in deep wilderness. Officially, the only predator that need concern me is the black bear which is generally shy of humans unless desensitized to human presence by careless garbage disposal and generally only dangerous when startled or reacting to a perceived threat to cubs.
Unofficially, both large bucks, moose and wolves (occasionally down from Canada) can be threats.
I treasure the peaceful quiet there. But when I realize the surrounding forest has gone dead silent--no bird movements or twitters, no scurrying ground squirrels, when even the wind seems to be holding its breath--my hackles rise. I pause, sniff the air, study the woods around me, and only move on when some intuitive, instinctual part of me is satisfied. Reason is of little use here.
When and where we evolved, we were prey. For a hominid in East Africa, or even an early modern human, that deep alarm system was invaluable. Finding myself alone in a sudden hush still triggers a hyper-alert state, one that served me well in the jungles of East Asia and in large cities around the world: that state can still make me stand silently for 15 minutes in the forest or cross the street to avoid the mouth of a dark alley in New York.
As for the associations you recently make between that trigger and what you've been reading--sure, that sounds like suggestibility, but even suggestibility can be useful if, say, you've heard reports of tigers in the area and then hear a rustling nearby followed by a sudden hush.
That alert/alarm systen is ancient and bypasses the reasoning mind for good reasons. It's not so much irrational as arational, and faster than logic.
If an empty car in the night-time parking garage gave me the creeps, I'd give it a wide berth. The cost of precaution is low, and the penalty for ignoring your own hackles rising can be fatal. One of the first things taught in urban self-defense courses is
don't ignore your instincts. Many millennia and hominid deaths went into arming you with them--ridiculing our own instinctive alarms and laughing our way into the maw of death is the premise of a thousand horror flick scenes.
When you find yourself alone, and it suddenly gets quiet--too damn quiet--honor your ancestors and stay alive.
Edited by Omnivorous, : No reason given.
"If you can keep your head while those around you are losing theirs, you can collect a lot of heads."