Your favorite vase lies broken on the floor, and your 8-year-old blames the cat. Is he telling the truth? Chances are, you can’t tell, according to a new study. Data gathered from 45 experiments involving more than 10,000 kids and adults suggest that although most adults think they know when a mumbling, fidgeting, shifty-eyed kid is deceiving them, they can only correctly identify lies 47% of the time. That’s no better than if they just guessed, researchers report in Law and Human Behavior. The findings also strengthen a long-held hypothesis: Kids become better liars as they age. Professionals like social workers and teachers are also slightly better than laypeople at detecting lies, the team found. The authors caution that their investigation was only a meta-analysis, which combines the results of many scientific studies, and that many of these projects weren’t conducted the exact same way—something that could shift results in one direction or the other. But they hope their paper will highlight important areas of future research, which someday might help parents, teachers, and neighbors better detect fibbing kids.