Final answer:
The period marked by a decline in fear of loud noises, falling, sudden movement, and strangers typically occurs as infants grow into toddlers. This is when children's cognitive and emotional development helps them understand their environment and the people around them better, easing their innate fears.
Step-by-step explanation:
The period marked by a decline in fear of loud noises, falling, sudden movement, and strangers is typically associated with the latter part of infancy into toddlerhood. During infancy, newborns tend to startle and show fear in response to loud or sudden noises which could indicate potential danger. This can include reactions to angry adult voices, thunder, or the cries of other infants. The infant turns toward these sounds and may blink their eyes. As they grow, they gradually begin to understand their environment better and develop coping mechanisms.
In line with Piaget's developmental stages, around the time when children start to develop object permanence, they also experience stranger anxiety. This occurs when a baby or young child is confronted with a person they can't fit into their existing understanding of people they know, which leads to distress and fear. Over time, as children's cognitive and emotional development progresses, they begin to lessen these fears as they become more familiar with the world around them and the people in it.