What is characterized by an automatic response to a specific stimulus in infancy?

The characteristic described by an automatic response to a specific stimulus in infancy is best defined as "infant reflexes." These reflexes are innate behaviors that occur automatically in response to certain stimuli, serving important developmental functions. For instance, reflexes such as the sucking reflex or the grasping reflex are crucial for survival and initial interactions with the environment.

These reflex actions highlight the early stages of neurological development in infants, demonstrating that certain responses are hardwired and do not require voluntary control, unlike voluntary movements that develop later as the child matures. While "reflex action" and "involuntary response" technically describe aspects of the same phenomenon, they do not specifically reference the unique set of reflexes exhibited by infants. Therefore, the term "infant reflexes" captures the essence of these automatic responses during the earliest stages of life.