You can never predict how a very tiny kitten will react when you bring her home. One who has just been taken from her mom may miss her, and while the owner will quickly fill the mom cat’s role, a pining kitten can be made to feel at home by letting her snuggle with a hot-water bottle or heating pad (on a low setting); either one will fill in for the high-temperature body of a mother cat.
Some kittens feel safe near the ticking of a wind-up alarm clock, since it apparently reminds them of their mom’s heartbeat. (Good luck finding a wind-up clock in the twenty-first century, though.)