It’s such a common experience that Jordy Kaufman, a senior research fellow at the Brain & Psychological Sciences Research Center at Swinburne University of Technology in Australia, decided to investigate whether something more was going on beyond “everything looks big compared to a newborn.”

“A lot of parents had expressed the feeling that they almost lost a baby when they got another one,” said Kaufman, who wondered whether parents were actually misperceiving the size of their youngest child.

Kaufman and colleagues initially surveyed 747 mothers, and more than 70 percent reported that their erstwhile youngest child suddenly seemed bigger when compared to the newest addition to the family. He then asked 77 mothers to estimate the height of one of their children between the ages of 2 to 6 years, which was then compared to the child’s actual height.