For most mammals, milk belongs to infancy. After weaning, production of lactase—the enzyme that breaks down milk sugar—declines. Many humans follow that same developmental pattern. But some populations evolved lactase…
Evolution
69 Articles
A baby who once smiled at everyone may begin hiding against a parent when an unfamiliar person approaches. This change, often noticeable during the second half of the first year,…
A young child’s endless questions can feel like a strategy for delaying bedtime. But research suggests that children usually ask questions because they genuinely want information—and they can recognize when…
Give one child one piece of candy and another four. The child receiving less may immediately protest. But reverse the rewards, and the favored child may happily accept. These reactions…
Grandparents frequently love their grandchildren equally—but across large populations, their average investment is not always equal. Studies in several Western societies often find a recurring pattern: maternal grandmothers provide the…
A baby who wakes repeatedly at night seems interested only in milk and comfort. But one provocative evolutionary hypothesis suggests that night waking may also delay the arrival of a…
Many babies happily taste whatever reaches their mouths. Then, around toddlerhood, the same child may inspect an unfamiliar vegetable as though it were dangerous. This developmental shift is called food…
A baby’s oversized eyes, round cheeks, small nose and high forehead form what scientists call the baby schema. These features do more than make infants look cute—they appear to capture…
Speak to a baby and your voice may transform without conscious planning: the pitch rises, vowels stretch, sentences shorten and the melody becomes exaggerated. This is infant-directed speech, sometimes called…
Give a child and an adult the same drink, and the child will often prefer a much sweeter version. This is not merely the result of advertising or permissive parenting—the…