startle reflex
Involuntary alarm reaction
The startle reflex is an involuntary response to sudden stimuli—a loud noise, unexpected touch, or flash of light.
The body flinches, muscles tense, eyes blink.
In newborns, the Moro reflex causes arms to flail outward then draw back in.
The response is hardwired, a remnant of defensive reactions shared across mammals.
- flinchInvoluntary retreat from threat
- joltAbrupt forceful shake
- gaspSudden sharp breath
- twitchInvoluntary muscular jerk
- jumpPropel oneself airborne
infant · newborn · arms · flailing · sudden · loud · noise · loud noise · jump scare · split second · primitive · brainstem · nervous system · knee jerk · fight-or-flight · fight or flight · adrenaline · heart rate
- body signalsheartbeat, pulse, brainwaves, brain waves, brainwave
- body responsesfight, flight, shivering, freeze, goosebumps
- instinctsinstinct, survival instinct, survival instincts, maternal instinct, gut instinct
- reflexesknee jerk, knee-jerk, clonus, blink, flinch
- stress reactionspanic, fear, fright, terror, horror
- baby sleepcrib, bassinet, swaddle, swaddling, nap
startle reflexvoluntary action
Deed done by choice
voluntary movement · conscious decision · executive action · learned behavior · conditioned response
startle reflexrelaxation response
Body's stress-reversing state
resting state · habituation · desensitization · tranquility · composure
startle, reflex, startled, startling, startles, reflexes, reflexive, reflexively, reflect