Research has found that children who start telling lies at age 2 or 3 — a year or two before most of their peers — tend to have a slightly higher IQ and an advanced ability to plan and control their actions (a process called “executive functioning”), notes Kang Lee, Ph.D., a professor at the University of Toronto’s Dr. Eric Jackman Institute of Child Study. That’s because lying takes more cognitive ability than simply confessing. If you ask a child, “Did you write on the wall?” she must both withhold the truth and dream up a fib. Plus, she must be capable of a little “mind-reading” to discern what you already know (“Mom saw me with the markers, so I can’t tell her I never had them”), a skill that Dr. Lee says is related to the development of empathy.