Cats may sometimes be fearful of new sounds, people or experiences, however how a feline is raised can positively or negatively change how well they handle new situations.
VCA Animal Hospitals reports that there are many reasons cats develop fears, one of which is a lack of exposure to people and other animals when they are young. Proper socialization is crucial for every animal to adapt to the different scenarios it will face in its life and owners are responsible for helping their cats get the exposure to live anxiety-free as adults.
According to VCA, kittens need to be socialized much earlier than dogs - between 3 and 9 weeks of age - so owners who get kittens need to start exposing them to new people and pets right away. Since cats are mostly housed indoors, this often requires a concerted effort to bring different experiences into the household to adequately socialize your new kitten.
For people who adopt adult cats, it is usually unknown what types of exposure the cats had while in their previous homes. In these cases, it is best for owners to let their new adult cat settle in and "do their own thing" at first. It is important to create a safe and comfortable environment and engage in play and cuddling when the cat initiates it. Once your adopted cat is comfortable with you, gradually begin exposing them to new people and other experiences to round out their socialization experience. You may consider using treats as rewards when your cat allows calm interactions with new people or experiences.