The startle response is an automatic reaction to sudden or unexpected stimuli, such as loud noises or quick movements. This reflex is part of the body's defense mechanism, preparing it to respond to potential threats. When startled, the body may jump, flinch, or experience a rapid heartbeat, which are all signs of the nervous system's activation. This response is often linked to the fight-or-flight reaction, which helps individuals react quickly to danger. The startle response can vary in intensity among different people and can be influenced by factors such as stress levels and past experiences with similar stimuli.